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Choosing the best power meter for you and me as road cycling enthusiasts is now easier than it has been in years. Prices have stabilized, performance has equalized, and options have normalized.

Our road bike power meter decision essentially comes down to how much beyond $/£/€300 we are willing to pay for installation convenience, pedal preference, model compatibility, or power data geekery. Based on those criteria, I’ve found that the best competitively performing and widely available options are power meters in pedals from Favero, Wahoo, and Garmin, on crank arms from 4iiii and Stages Cycling, and on crankset spiders from Quarq and Power2Max.

At the same time, using a power meter has become broadly accepted by roadies as a key to enabling us to ride faster, a status traditionally held by a new bike, wheelset, or other gear that typically costs far more than a cycling power meter does.

While I still want to know all the deets when a cycling friend gets anything new, I know I’ve got to be on my game when a fellow enthusiast shows up for a ride with a power meter on their bike.

In this review, I’ll tell you more about how road bike power meter products are maturing, how to pick the best power meter for your needs and preferences and give you my reviews of the best power meters that fit them. (Click on any of those phrases to go directly to the part of the post that covers that topic.)

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In the second half of the last decade, the number of companies jumping into the road bike power meter business with proven, unproven, or announced but undeveloped models tripled the handful that competed for business before then.

Many consumer market booms these days are driven by a new design or application of technology that yields a considerably lower-priced product and reaches untapped demand many times larger than was currently being served.

In the case of power meters, Stages Cycling was the first to put a strain gauge sensor on the left side crank arms of popular Shimano crankset models back in 2013. They sold them for just under $1000 or between 2/3 and 1/2 the price of the best-selling SRM and Quarq power meters that were bolted to the crankset rings (a “spider”) or Powertap models that went inside the rear wheel’s hub.

By doing so, Stages power meters reached the occasional road racer and nerdier end of the enthusiast road cycling segments. These were far larger, more consumer-oriented groups than the pro, triathlon, and top-category amateur racers who were the primary buyers of cycling power meters before, mostly to give their personal coaches the data to improve their individual training programs.

Seeing Stages’ success, many companies both experienced in the cycling market and new to it jumped in. These companies introduced, or at least announced, power meters that used strain gauge sensors on crank arms and spiders and in new places, including pedals, bottom-bracket axles, and even inside shoes.

The relatively lower prices of most new cycling power meters drove those making long-established models to drop their prices once the new entrants proved their technology worked and saw their sales grow.

More roadies bought these new and lower-priced established models and learned how to use them to improve their performance without needing a coach. As there was apparently a lot of profit to be made, the hype machine spun quickly, and new price drops attracted more cyclists, retailers, new models, updates, performance claims, analytical features, etc.

And then, about five years after all of this new product and market energy started, things began to calm down, sort out, and consolidate.

While still growing and certainly not old, the road bike power meter product market seems like a maturing young adult leaving behind a pretty wild time of adolescence.

Specifically, I see that:

Options have normalized: As in any maturing market, road cycling enthusiasts have had enough time to focus on a shorter list of power meters and suppliers that best suit their budget, performance needs, and preferences. Those that don’t have broad appeal have either been marginalized or exited, either through acquisition or getting out completely.

For example, rear hub power meters from Powertap, the company that made what was once considered a benchmark location and product for measuring your power output, are now gone from the scene. SRAM’s Quarq power meter unit bought the company, perhaps to use their greater retail distribution power and engineering resources to revive the brand and its fledgling product line, but have now discontinued the Powertap hub, pedal, and spider products.

For a variety of reasons, the Powertap products and others that tried to get in or stay in were not competitive in the maturing power meter market.

Options have normalized

With three at the start and after a boom of 15+ companies introducing power meters, seven companies now serve most road cyclists.

Direct force or strain gauge-based road bike power meters are now only made for pedal, crank arms, and crankset spider locations. And as I noted in the introduction of this post, there are only two major suppliers of power meters for each of these locations.

Others, including SRM, Verve, Specialized, and Rotor, are smaller or niche power meter suppliers either because of their prices, design, performance, or distribution.

Remaining dealer inventory and outdated websites notwithstanding, Easton, Pioneer, FSA, Team ZWatt, Polar, and Watteam have stopped making power meters. Ashton Instruments, Xpedo, Limits, Luck, and untold others announced products that never made it into production.

Shimano, obviously a major player in the cycling drivetrain components business, does make a dual crankarm power meter they include on some of the pricier bikes equipped with its Dura-Ace groupsets. SRAM also includes their Quarq power meters on expensive bikes that are included with some of their gruppos.

Unlike SRAM, Shimano currently appears more interested in using its power meter as a profitable OEM upsell opportunity for the high-end bikes it goes on rather than as another standalone product to sell in the aftermarket. Shimano’s aftermarket products are typically competitively priced, have a differentiated, patented design, and are widely distributed. Their power meter has none of these attributes.

New iterations of existing models will certainly come out over time. Quarq, or another power meter or cycling industry supplier, may add a new product for a location where they don’t currently make one, likely in a pedal power meter.

The cost and complexity of power meter development in a market that has already seen tremendous price compression make me think it’s very unlikely there will be many successful new models coming from companies that don’t already make technically proven, well-accepted, and profitably priced power meters today.

SRM, one of the original power meter suppliers and not to be confused with SRAM, is now making the X-Power pedal system based on Shimano’s SPD mountain bike platform. Notably, this is a different power meter pedal than the overpriced and hard-to-calibrate SRM Look Exact based on the Look Keo road bike platform.

Garmin now makes the Rally series power meters that add the Shimano SPD SL road bike and SPD mountain bike pedal platforms to the Look Keo one they already make (reviewed here). The Rally is essentially the same Vector power meter they made before, only rebranded for a wider range of pedal types.

Favero, which also started with a Look Keo power meter pedal called the Assioma, now makes the Assioma Duo-Shi for SPD SL pedals (except the Dura-Ace). Again, it’s the same power meter they’ve been making all along, adopted for Shimano pedals.

Wahoo followed with the POWRLINK ZERO based on the Speedplay pedal platform.

Performance has equalized: Power meters are often marketed around their accuracy. Claims run between +/- 2.0% or +/- 1.0%. If you are a road cycling enthusiast producing 300 watts, that 1.0% difference is  +/- 3 watts. That amount doesn’t matter to anything other than your bragging rights and is easily overwhelmed by a dozen other things that could affect how much power you can translate to the road, from your wheel’s stiffness to chain lube to you getting a better night’s sleep.

Power meter consistency, or getting the same reading day after day for the same power output, is more important than the absolute accuracy of your power meter readings. However, I’ve not seen power meter suppliers make claims about their product’s consistency.

Fortunately, there have been a lot of evaluations of the actual performance of power meters done by independent testers and publications I trust. The differences they show in the accuracy, consistency, drop-outs, top-end power, temperature compensation, communication to your head unit, and other measures of the best power meter models from the leading companies are nearly non-existent or so small that they shouldn’t matter to almost all road cycling enthusiasts.

I realize I’m taking a risk in speaking for all of my fellow roadies with that last italicized statement. Note that I’m not talking about pro or Cat 1 and 2 road racers or time trialists, triathletes, track cyclists, or their personal coaches. But frankly, I think there are probably many things that are more important to their training and performance, even for them, than these small differences between the best power meters.

There are differences in battery life, another performance measure, and how you recharge or replace your battery, a feature more than a measure. There are also some differences in reliability. I’ll say more about these things in the reviews below.

This is probably as good a time as any to remind you that you want to zero-offset nearly every power meter at the beginning of each ride and certainly when you transfer it between bikes regardless of the type of you are using. If you don’t, there’s no guarantee that it will read your power consistently.

It’s easy. Put your bike outside in the temperature you’ll start your riding in while you put on your shoes, gloves, etc. Turn on your head unit, move cranks or pedals into the prescribed horizontal or vertical position, and push the zero-offset button on your head unit or let it calibrate automatically if your can do that. Within a few seconds, the zero-offset is done and start your ride.

Acceptance has been realized: Once thought to only benefit high-level racers, cycling power meters are now accepted as standard equipment by those who want to train better, ride faster, manage their efforts more efficiently, and do inside rides on Zwift. That means serious amateur cyclists like you and me. 

The best power meters have moved well beyond an analytical aid for personal coaches. As more roadies use training tools and programs like Zwift, TrainerRoad, SYSTM, FasCat, and others (see my training plan review) that track their progress on Training Peaks, a power meter has become accepted as an essential training tool to measure your progress and guide your daily and long term plans.

Do two or three 6-week training blocks well with the help of a power meter, and you could increase your average or normalized power output during a ride by 10 to 20 watts or more. This would allow you to ride faster or save energy at the same speed. That amount of increase is comparable to the drag saving you’ll get from an aero bike or deeper set of carbon wheels at a far lower cost.

When you know what power you can hold for 1, 5, 20 minutes, and longer, you can also use your energy on rides and in events more efficiently. You can monitor how much energy you burn overall and at key parts of a ride. And once you know this, you’ll know how many and how hot to burn those metaphorical matches you have during challenging sections of a route.

A power meter set up on the bike you use for inside rides or built into your smart trainer has also become the tool you need to calculate your power-to-weight ratio. More so than speed or heart rate, your power-to-weight ratio is key to picking out the right Zwift group rides and measuring and managing your efforts during any ride in Watopia and other virtual worlds.

If you are new to training with power, here are two books I’ve read, continue to refer to, and highly recommend. Hunter Allen and co-author Andy Coggan wrote Training and Racing with a Power Meter, which laid the foundation for much of what everyone is doing now with power. Friel wrote The Cyclist’s Training Bible, the original and still the best resource I’ve ever read on endurance training. Friel’s newer book Fast After 50 is for those of you who want to keep improving despite your age.

Unnecessary features have been neutralized: There’s been an argument from some reviewers and suppliers that determining your power by adding how many watts come from your left and right legs is better than measuring your total power from what they produce together or doubling what one leg produces.

While it’s certainly interesting to know how much power each leg generates or their relative strength, I’m unaware of any training prescriptions that come from having this knowledge for riders with normal power imbalances despite having this analytical capability in some power meters for 5+ years.

Unless you are coming off an injury, most riders will have an imbalance somewhere between 55/45 and 45/55. Few will produce 50% of their total power from each leg and a 2% variance is very common. That seems perfectly normal since our legs are usually not exactly the same length and few of us are “ambipedal” or use our right and left feet and legs equally.

While I’m not privy to what some private coaches may be telling their high-level athletes, I’ve not heard or read of training guides, fitters, or power meter suppliers suggesting that you do something different in your bike or strength training, bike or shoe-fitting, or anything else to even up your power output.

No doubt, it’s interesting to know that you might have a 2%, 3%, or even 5% imbalance. But, recognize that you’ll pay nearly twice what you would in the initial purchase price for a pedal or crank arm power meter to have this information that you physically won’t do anything with and may mentally obsess about.

While not comprehensive, my discussions with stores selling road bike power meters show a clear preference for pedal and crank arm power meters with a single sensor that measures and doubles the power you produce from your left leg.

To a lesser degree, other proprietary analytical features built into Garmin and other bike power meter software have been neutralized except for the geekiest enthusiasts or Garmin-centric among us.

Pioneer’s crank arm power meters were differentiated around some very cool-looking pedal stroke and other analytical features. As I mentioned earlier, they’ve left the business. I don’t know how much their feature strategy played a part in their success or lack of it, but it certainly didn’t save them.

As best I can tell, none of the six leading power meter suppliers successfully depends on proprietary analytical features to separate themselves from the others.

Prices have stabilized: As you might expect from any mature business, power meter prices have stabilized. Only six large-volume power meter suppliers remain, of which two make pedal power meters, another two make crank arm ones, and two others make spiders.

Starting prices went down in the last decade from about $1500 to $1000 to now between $300 and $600 for road bike power meters made by the six. The other suppliers exited the business or have remained in lower-volume niches usually with higher-priced products.

With demand continuing to grow and after all of this sorting out and consolidation leaving two major suppliers competing for each power meter location, I think it’s unlikely we’ll see more price declines until demand flattens out or shrinks. Indeed, save for the occasional sale at a specific retailer, I haven’t seen notable price drops in this decade.


If you’ve been waiting for lower prices or fewer choices, or a better understanding of how a road bike power meter can improve your speed and performance, you probably haven’t been alone. But, with the market maturing in the ways I described above, picking the best power meter for you and your needs has become much easier.

With little to no difference in how well road bike power meters perform, choosing between them comes down to how much extra you are willing to pay for a shortlist of things that may be more or less important to you.

Those things are:

* Price – You don’t need to spend more than about $/£/€300 for a power meter that will give road cycling enthusiasts all we need to get the performance benefits of training and riding with power. As you’ll see below, there are several reasons why you can and, depending on your needs and preferences, might want to spend more, but that $/£/€300 amount is the price floor today.

* Installation convenience – If you ride one bike, then a left-side crank arm power meter is the least expensive way to go. If you have more than one road bike where you want to use your power meter, power meter pedals are the easiest kind to move from one road bike to another.

Want to move your power meter between your road and gravel bikes? A crank arm power meter is your least expensive option. Unless you never plan to put your foot down in the dirt or gravel off-road, you don’t want to use road bike pedals. Even if you have a Shimano GRX gravel crankset on your gravel bike, it uses the same left crank arm attachment fittings as on Shimano road groupsets.

* Pedal preference – If you use Shimano and Look pedals, Favero’s Assioma or Garmin’s Rally power meter pedals will suit you and be the most convenient power meter to move between road bikes. Wahoo’s POWRLINK power meter pedals meet the needs of those that prefer Speedplays.

All of these come at a price premium to a single-sided crank arm power meter.

If you prefer TIME or another road or gravel pedal model, then go with a left-side crank arm power meter as the lowest-priced option and the next easiest one to move between bikes. Dual-sided crankarm and spider power meters are more expensive and take more work to switch from one bike to another.

* Model compatibility – Power meter pedals work with any crankset. There are zero compatibility issues with power meter pedals.

Most enthusiast-level road bikes have Shimano cranksets, and most others have those made by SRAM or Campagnolo. Both Stages and 4iiii sell Shimano crank arms or cranksets with their power meters installed on them. Only Stages sells SRAM, and Campy crank arms with power meters pre-installed, and only for some of their crank arm models.

However, Stages and 4iiii will install their power meter sensors on some of your own gear rather than buying a new crank arm or crankset with their installed power meter sensors. While you’ll have to be without your gear for 2-4 weeks, this can keep your cost down and give you the option to get a power meter on brands of many other road crank arms that you wouldn’t otherwise be able to.

Stages crank arm power meters

Acceptance among enthusiasts has led to a wide range of compatible solutions.

Spider power meters also require that you use a model compatible with your crankset. Quarq, owned by SRAM, focuses on SRAM cranksets but doesn’t offer much for owners of Shimano and other brand cranksets unless you want to change out your crank arms and bottom bracket.

Power2Max, the other major spider power meter supplier, sells spiders that don’t require you to add new arms for many more brands than Quarq but not for Shimano due to the big S’ unique design.

Velocomp makes a power meter you hang on your handlebars and is, therefore, as compatible as pedal power meters. However, it uses measurement technology that can provide 5% or greater variation in your power meter readings if you regularly change positions on your bike, as most of us do. Further, it costs around $300, the same as the least expensive crank arm power meters. For those reasons, I don’t recommend it.

* Power data geekery – If you want to totally nerd out on power data, you’ll probably want left and right-leg independent measurement capability that is only possible from power meters with sensors in both pedals or crank arms.

Spider power meters give you total power and have an algorithm to estimate L/R metrics based on how you torque the spider during your pedal stroke. While I’ve found the calculated balance is within 1-2% of what you’ll get from independent measurement over the course of a ride, it’s not a true L/R measurement for those of you that insist on it.

There are various pedal balance, efficiency, and “smoothness” analytics over different time intervals you can measure if you have L/R power measurement.

Favero Assioma pedal power meters also provide Garmin’s Cycling Dynamics suite of metrics captured exclusively on Garmin head units. They can show you things like how much time you spend standing vs. seated, how much power you are putting out in each part of your power stroke, and where your power is distributed across your pedal.

It’s all very interesting data that may excite the geek within us. However, we cannot do much with this data other than perhaps become obsessed with it. And it costs more to feed that part of our habit.

And yes, I have independently left/right power meter cranks. But, after a few summers of reviewing and playing with them, I’ve found worrying about a percent or two difference between my left and right leg is a major distraction to my training focus and the pleasure of riding my bike. I do nothing differently with that knowledge and nothing in the Cycling Dynamics suite that would influence my training.

I will note that some enthusiasts have a power meter but don’t train to any kind of plan that uses it. This renders their power meter a worthless and expensive toy. Don’t be that guy or girl.

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As I wrote in the opening of this post and detailed in the sections above, no performance differences should matter to most road cycling enthusiasts between the six market-leading and widely available road bike power meter options.

Instead, you should choose among them based on how much beyond $300 you are willing to pay for installation convenience, pedal preference, model compatibility, or power data geekery.

Power meter criteria comparison

Below, I’ll review the leading pedal, crank arm, and crankset spider bike power meters against those criteria.

Other cycling power meters made for roadies either serve more narrow groups of enthusiasts or are higher-priced or both.


Power Meter Pedals

Favero Assioma Duo (left), Garmin Rally RS200, Wahoo POWRLINK

A power meter built into a road bike pedal is the easiest to install and transfer between bikes. It is also compatible with any road crankset a cyclist might own. This makes pedal power meters like the Favero Assioma among the most attractive options for enthusiasts who want to use a power meter. This is especially the case if you have more than one bike or different model cranksets on the bikes where you want to measure power.

And while there’s no significant performance or training benefit or prescription for roadies from measuring and analyzing independent left and right power sensor data, power meter pedals are equipped to do so in ways that fewer crank arm power meters outside Shimano ones can and that spiders can only estimate algorithmically.

Favero makes the dual-sided Assioma DUO-SHI power meter spindles to use with your own Ultegra or a handful of lower-tier Shimano road pedals for about US$660/£8780/€600. You replace the spindles on your current Shimano road pedals with the spindle and attached power meter pod that comes with the Assioma DUO-SHI.

If you already own Shimano pedals, the Assioma DUO-SHI is about 2x the price of the least expensive, left-side only 4iiii and Stages crank arm power meters or the cost to have their sensors installed on your own left crank arm.

They aren’t made for Dura-Ace pedals and aren’t sold with a single or left-side-only option.

The Assioma DUO-SHI has a wider spindle than the one it replaces in your Shimano pedals. With a width or “Q-Factor” from the outside edge of your crank to the centerline of the pedal of 65mm, it’s about 10-12mm wider on each side than most pedals or power meter pedals.

This difference was much discussed and me-thinks incorrectly judged negatively for the DUO-SHI when it first came out. Fitters I’ve talked to estimate that over half the riders they’ve worked on, especially those that are tall, have large feet or have tight hip flexors from sitting in an office chair day after day need spindles longer than the common 53-55mm Q-factor of other power meter pedals.

Placing Shimano, LOOK, or Speedplay cleats more inside or outside on your shoes can give you up to 5mm more or less width than setting them right in the middle. So the effective ranges are more like 50mm to 60mm for most and 60mm to 70mm for the DUO-SHI.

This short video segment from a Peak Torque review of the DUO-SHI explains this in more depth.

Oh, and if you also ride a gravel bike or mountain bike, know that cranksets used on those bikes already push your feet out much more than the 10mm or so difference you’ll get with the cleats placed in the middle of the road shoes you use with these power meter pedals.

If you are uncertain about what Q-factor is best for you and whether that should affect your power meter pedal choice, I encourage you to talk with your bike fitter. Your knees will thank you, and your power output will be more efficient (aka higher) with the right width.

Favero also makes the Assioma UNO US$495/£450/€440, which are Look KEO-style pedals that have a left-side-only power meter pod attached to their spindle. At that price, it is 50% ($150) more expensive than the lowest-priced crank arm option.

If you want Look KEO pedals with left and right sensing power meter pods, Favero sells the Assioma DUO for US$760/£595/€690. These are more than 2x the lowest-priced crank arm option and also more expensive than the DUO-Shi option for those of you who have Shimano road pedals.

Favero’s Assioma DUO-Shi and DUO power meters become price competitive against higher-end Shimano crank arm power meter models, and those made for SRAM and Campagnolo crank arms. They are also less costly when compared to spiders, where you have to add some combination of crank arms, chainrings, or bottom brackets to make them compatible.

Garmin’s single-sided US$650/£580/€650 Rally RS100 (Shimano) and RK100 (Look) power meter pedals are over 2x ($350 more) the price of buying or putting a sensor on your Shimano crank arm. They are also slightly more than the dual-sided Favero Assioma DUO-Shi and not much less than Assioma DUO. At US$1100/£970/€1100, the Rally RS200 (sensors on both sides) is 1.5x to 2x the price of the dual-sided Favero Assioma models.

Again, if you don’t have Shimano pedals, you need to buy them for the Assioma DUO-Shi. The Shimano Ultegra PD-R8000 pedals, the highest level and most expensive ones that work with the DUO-Shi, cost US$200/£133/€129 through these links to Competitive Cyclist, Power Meter City 10% off w/code ITKPMC10, Planet CycleryMerlin, and Tredz 10% off w/code ITKTDZ10. These are all stores that I recommend because they have very competitive prices, top customer satisfaction ratings from fellow cyclists as reported by independent services, and a great selection of gear for road cycling enthusiasts.

Even if you add in the cost of these pedals, the Assioma DUO-Shi are better priced than the Rally pedals.

As with the Garmin Vector, the Rally uses a coin cell battery accessed by a battery door. Poor seals on the Vector models led to high-reliability issues reported both by users and dealers. In my testing, Garmin has solved this problem with the Rally.

While the Rally’s claimed battery life is roughly 2 to 3 times Assioma’s 50 hours, the Rally requires a less commonly available button cell battery. By contrast, you can recharge your Assioma batteries at the same time you recharge your head unit, lights, or electronic shifting batteries.

With the introduction of Wahoo’s POWRLINK ZERO in February 2022, Speedplay pedal loyalists finally have a power meter to call their own. Like Favero’s design, the POWRLINK power electronics sit in a pod on the spindle between the crank arm and pedal itself.

At US$1000/£850/€1000 for the dual-sided POWRLINK and US$650/£550/€650 for the single-sided version, it is priced similarly to the Garmin Rally power meters. Battery life is a more-than-ample 75 hours, and, like the Favero, they recharge using clip-on power cables. The POWRLINK gives you the power and cadence data you need but doesn’t calculate the suite of pedal-specific metrics that Garmin and Favero do but that no one knows what to do with.

While a couple of trusted independent testers had access to it for 6-12 months before launch, most of us are just getting our initial season of experience with it. The POWRLINK performed well – accurate and consistent – on my test rides and those of the longer-term testers. Wahoo has proven its power measurement experience from its smart trainers and has significantly retooled the Speedplay line and manufacturing facilities since acquiring the business. This makes me hopeful, but still waiting to verify its long-term reliability over the course of several seasons.

SRM started selling its first-generation EXAKT Look KEO-based pedal power meter in 2018, but it is far higher priced than the Assioma and has been shown to give inconsistent power meter readings in independent testing. SRM appears to have moved on from this joint project with Look and is now focusing on a new SPD mountain bike power meter pedal system but it’s very, very hard to find at stores.

Powertap, purchased by Quarq, stopped making power meter pedals in 2020 after a couple of generations of models that didn’t perform as well or weren’t as price-competitive as Favero’s.

With Favero and Garmin giving you both Shimano and Look power meter pedal options and Wahoo offering a Speedplay one, most of us roadies can now find a competitive power meter pedal solution to suit our pedal platform preference.

But, if you don’t have a pedal design preference and are attracted to the ease of installation and universal compatibility that pedal-based road bike power meters offer, I recommend the Favero Assioma UNO (Look) or DUO-Shi (Shimano) for its superior price and proven long-term reliability. If you are a Garmin fan but don’t want to pay the premium, I suggest getting a crank arm power meter.

I’ve written a dedicated review of power meter pedals if you want to go into more depth.

To order the Favero Assioma power meters, you can click on these links to Competitive Cyclist, Power Meter City, Amazon, and others in Know’s Shop, all stores I rate highly for their competitive pricing and customer satisfaction.

The Garmin Rally is available at these links to Competitive Cyclist, Planet Cyclery, Power Meter City, Tredz, and Know’s Shop.

You can find and order the Wahoo POWRLINK ZERO at these links to Competitive Cyclist, Power Meter City 10% off with code ITKPMC10, and Tredz 10% off w/code ITKTDZ10.


Crank arm power meters

4iiii (left) and Stages Cycling power meters

For as little as US$300/£299/€342, left-side crank arm power meters from 4iiii and Stages Cycling give you the lowest price options to ride with power while still giving you all the performance and metrics most road cycling enthusiasts would ever need.

While their claims differ, actual differences in their accuracy, consistency, battery life, or other performance measures are hard to see from tests conducted by independent parties. Even with the differences that probably do exist, they are so small or insignificant that they are unlikely to affect your training and performance.

4iiii and Stages Cycling have been making power meters for years and have become very reliable after several model iterations. They use readily available CR2032 coin cell batteries and last 100+ hours, in my experience.

Installation and Transfer: While not as easy to install and transfer as a pedal power meter, crank arm power meters are easier to set up than a spider power meter.

Here’s a video on how to replace a left-side crank arm and an entire crankset. As an enthusiast with no wrenching experience and indeed never having changed a pedal, crank arm, or crankset myself before getting my first power meters, I can assure you this is all quite doable in short order.

It is also wise, and I’d highly recommend using a small torque wrench when fastening your left crank arm. This ensures you don’t over- or under-tighten your crank and, equally important, that it doesn’t move around on you. After installing or transferring, you should run a zero offset like every day before you ride, even if you don’t make any changes.

Most crank arms tighten with less than 15NM (clearly noted on the crank arm), requiring a much smaller, very portable, and inexpensive wrench.

Measurement and Analytics: With power sensors on both your left and right crank arms, you can get independent power measurement, pedal balance, efficiency, and “smoothness” analytics. But, if you want to fully geek out on the Cycling Dynamics metrics, you’ll need a Garmin Vector or Favero Assioma pedal power meter.

Pedal Preference and Model Compatibility: Crank arm power meters also don’t limit your choice of pedals the way a pedal power meter does.

However, there are limits to the range of models that crank arm power meters are compatible with beyond Shimano cranksets, the most widely used ones among roadies.

And that crankset model range is probably the biggest difference in choosing between a 4iiii and Stages power meter.

Depending on the crankset model, you can buy a crank arm or crankset with power meter sensors already pre-installed on them or send the crank arm or crankset you already own to 4iiii or Stages to have the sensors installed at their factory.

Both companies sell Shimano 105 ($300), Ultegra ($350), Dura-Ace ($450), and GRX 810 ($350) cranks with their power meter sensors pre-installed to one or both of the arm’s inside surfaces.

I do recommend 4iiii and Stages left side crank arms for Shimano groupsets. However, I don’t recommend right side Shimano crank arm power meters from 4iiii, Stages, or anyone else supplying them including Shimano. There is something about the design or manufacture of the newest Shimano Ultegra and Dura-Ace models that independent testers have found produce inaccurate power meter readings.

Stages also sell left-side only crank arms with the pre-installed power meter sensors for SRAM BB30, GXP cranks, and  Campagnolo Chorus, Record, and Super Record 11 and 12-speed models. These sell for a good deal more than the Shimano ones, with SRAMs running $500-$570 and the Campags ranging from $600 to $850.

If you own one of the more common Cannondale, FSA, or Easton models, Stages also makes pre-installed left-arm power meter cranks for some of their models.

Now, if you can part with it for a few weeks, you can get one of their power sensors factory installed at 4iiii or Stages onto your own left-side crank arm. And it will only cost you $300 to do so regardless of whether you own a 1st, 2nd, or 3rd tier of Shimano, SRAM, or Campagnolo.

Both companies will also factory install sensors on some Cannondale, FSA, and Praxis left arms you may own.

If you want sensors factory installed on both crank arms, 4iiii will do it for $500 on the same range of Shimano cranksets I listed above (but I don’t recommend it for the right side Shimano arms) plus some SRAM, Campy, FSA, and Praxis cranksets. Stages will factory install dual-sided sensors for $550 on the three road groups.

You can click on these links to see the complete list of crank arms and cranksets that Stages and 4iiii (left, right, both) will factory install their sensors on.

You can get a 10% discount on 4iiii products when you link to one of my top-ranked stores Power Meter City and use the exclusive code ITKPMC10 for In The Know Cycling readers. They are also available using these links to Merlin, and Tredz 10% off w/code ITKTDZ10, and others in Know’s Shop, all stores I recommend.

For Stages power meters, order using these links to stores I recommend including Competitive CyclistPower Meter City, 10% off with code ITKPMC10, Merlin, Tredz 10% off w/code ITKTDZ10, and others in Know’s Shop.


Spider crank arms

Power2Max (left) and Quarq power meters

Spider power meters that bolt onto your chainrings are one of the original power meter designs. Because of their design longevity, spiders are often viewed as a power meter benchmark, have been improved to provide amongst the highest accuracy rates, and are available for a wide range of crankset models.

Road, time trial, triathlon, and track racers, along with traditional roadies of all stripes, often favor spiders for their proven record over many years of experience.

Power2Max and Quarq power meters serve the broadest range of road cycling enthusiasts and crankset models with the most competitively priced products. They are both highly reliable.

Others you may know – SRM and Shimano – make significantly higher-priced spider power meters that serve smaller customer groups. Still others – FSA, Team Zwatt, and PowerTap no longer make spiders, though you may still see some for sale.

A spider can be the best, cost-competitive solution to fit your current drive train situation and how you intend to use a power meter. You’re a good candidate for a spider if you plan to focus your power meter measurement principally on one bike, already have a crankset model that only requires you to add the spider to get you going with power, don’t much care about independent leg power measurement or pedal stroke analytics, or want to use your preferred Shimano, Speedplay, Look, Time or other pedal models.

If some of those situations don’t describe you, a pedal or crank arm power meter will likely be a less costly and more suitable way to go. Here’s why.

Installation and transfer: A spider power meter takes a little more work (though not a ton) to install than the other types. If you’ll be using it mostly on one bike, not a problem. Install it yourself if you are handy and have the tools. Have a friend or shop install it if you’re not.

To move your power meter spider between bikes, you’ll need to move the entire crankset, similar to the way you would one with power meter sensors on both crank arms. It’s certainly doable but it will take 15-20 minutes out of your riding time to make the switch and clean up once you get good at it. This compares to 5-10 minutes to switch your pedals or left crank arm. The video in the section above on crank arms shows you how.

You’ll also need to have the same bottom bracket on any bike you want to put your power meter-equipped crankset on.

Price: Since a spider or spider power meter connects the drive-side (right) crank arm to the chainrings, it is made for specific crankset brands and, sometimes, models. Depending on your crankset, you may only need to buy the spider. That’s the least expensive solution and can cost no more than US$400-$500

To put a Power2Max or Quarq power meter on your bike, you may need to change out your crank arms. With some, you’ll also need a different bottom bracket and/or chainrings. That can boost the price to between US$600 and $800 or more and leave you with an entirely new crankset that doesn’t perform as well or look as integrated with your groupset as the ones you replaced.

Model Compatibility: The need to change crank arms is why Power2Max and Quarq power meters are not a great solution for Shimano crankset owners. Shimano now makes its own crankset power meter for Dura-Ace and likely Ultegra models in the future. SRM has long made a Dura Ace spider power meter. However, both a far more expensive than a dual pedal or crank arm solution.

Instead, spider power meters are typically more cost-effective if you have a SRAM crankset or one made by Specialized Cannondale, Rotor, FSA, Easton, or Praxis.

Power2Max spider power meter

Power2Max makes spider-only power meters for the widest range of cranksets including those who already own many Rotor, SRAM, Cannondale, or Specialized cranksets and won’t need to change their crank arms. These sell for US$490/€490 and up for their NGeco models that claim 2% accuracy and use a coin cell battery that should last you an entire year before needing to be replaced (400 hours). You don’t get estimated left/right power balance or pedal smoothness with the NGeco spiders but for $50/€50 each, you can buy a software upgrade that will give you that data.

For twice the price, US$940/€990 and more depending on the model, you can get a Power2Max NG that claims +/- 1% accuracy, gives you faux left/right balance, pedal smoothness, and torque efficiency data, and a rechargeable battery that goes about for a season (150 hours) between charges.

Both lines of spiders can also be delivered with new crank arms for FSA, Rotor, Easton, and Campagnolo cranksets.

You can get Power2Max products when you link to one of my top-ranked stores Power Meter City. They are also available at the company’s online store here.

Quarq power meters

Quarq, owned by SRAM, has a more SRAM-centric product line. They make spiders for the full range of SRAM’s newest electronic Red and Force 2x and 1x AXS groupsets and their older mechanical Red and Force and cranksets.

Beyond a spider power meter made specifically for those of you with Specialized S-Works carbon cranks, Quarq takes a more agnostic approach than Power2Max in serving other crankset owners.

Rather than try to fit their spider to your cranks, Quarq sells you the spider along with their Quarq or SRAM cranks. While their non-AXS spiders alone are competitively priced at US$399, you’ll need to add roughly US$200 to $400 for Quarq, Force, or Red level crank arms if you don’t already own a SRAM crankset. And, if you don’t have one, you’ll also need a DUB or EXP bottom bracket (US$40) to go with those cranks.

Quarq’s DZero (5-bolt) or DFour (4-bolt) spider power meters fit the chainrings used in most of the leading cranksets that you may own. You can also add rings to go with these spiders for another US$180.

It’s a modular approach that starts competitively but gets more expensive if you don’t own SRAM cranksets. But, Quarq’s long track record of performance and reliability, and its large footprint at SRAM dealers make it a solid option if a spider power meter is a good solution for your situation.

Pedal Preference: If you have a strong pedal preference, and it’s not for the Look Keo design, the spider power meter doesn’t limit you in the way the Favero or Garmin power meter pedals do.

Measurement and Analytics: A spider power meter measures your total power rather than adding your left and right power (dual pedals and crank arms) or doubling your single-leg power (left-side pedals and crank arms).

After all, there’s only one spider, and it’s bolted to the chainrings and torqued at a given cadence by both crankarms and pedals to produce a power reading.

Instead, Quarq and P2M road bike power meters use algorithms to estimate your left and right leg power balance. They promote “dual-sided power metering” and “separate left-right power balance” even though they don’t measure it directly from power meter sensors from the left and right sides.

Some reviewers say these spiders mirror true independent leg-measuring power meters in side-by-side tests, while others say they don’t. My experience riding simultaneously with the spider, dual-side crank arm, and pedal power meters shows a 1-2% difference in the estimated and measured left/right power balance values after 1-2 hr long rides on various terrain.

This is one of those po-ta-to vs. po-tah-to differences that shouldn’t result in, as the lyric goes, deciding to call the whole thing off. For me, the reasons I’ve reviewed above are more important ones when deciding whether or not to buy a spider power meter, unless your inner geek tells you otherwise.

Through this link at Power Meter City, you can also get an exclusive 10% discount on Quarq power meters using the code ITKPMC10. They are also available using these links to the following stores I recommend: Competitive CyclistPlanet Cyclery, Merlin, and others in Know’s Shop.

* * * * *

Thank you for reading. Please let me know what you think of anything I’ve written or ask any questions you might have in the comment section below.

If you’ve benefited from reading this review and want to keep new ones coming, buy your gear and kit after clicking the store links in this review and others across the site. When you do, we may earn an affiliate commission that will help me cover the expenses to create and publish more ad-free, subscription-free, and reader-supported reviews that are independent, comprehensive, and comparative.

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Thanks, and enjoy your rides safely! Cheers, Steve.


  • This is a really great summary!
    In my experience, any leg imbalance is quite consistent for a person. Since single sided power meters actually double the watt of your one leg, to estimate the power of two legs, a 3% L/R imbalance at 300W starts out being 9w but is then doubled to 18w, which could be a problem. That’s why 4iiii have a great advantage compared to Stages, because 4iiii allows you to adjust the ‘scale factor’. So if you have the possibility to compare your single side crank arm power reading to a smart trainer (consider drivetrain loss), you may calculate the imbalance, adjust the scale factor (in this case 0.94) and have the 4iiii report corrected numbers!

    • Henri, Thanks for your kind feedback and for adding the tip on the 4iiii scale factor.

      To follow up on your example, even if you don’t adjust your power meter for the imbalance, is there anything you would do differently with a reading of 282 vs. 300 watts or a 3% known imbalance as long as those readings are consistent? While you might feel better about yourself with an 18 watt higher reading (even though you are producing the exact same power), what if I or a mate told you that your power meter consistently reads 2% higher than others? At least for now, and after 5+ years of having independent L/R measurement capability, I’ve not read or heard about different training approaches because of small imbalance or even the suggestion from credentialed coaches that you should strive for a balance. And as long as your power meter reads consistently and your L/R balance is consistent, you should do the same training and get the same benefits of training with any of the power meters I’ve reviewed above.

      Good news for us roadies, there are many other things that have a real effect on our power output and speed that we can worry about! 🙂 Training program, aero position, shaved legs, chain friction, etc. Any of those will keep us busy for a long time. Cheers, Steve

      • Hi Steve
        You’re right, power number precision (repeatability) is relevant and accuracy is not so much.

        Only exception is when mixing different devices. In in my case, mixing indoor workouts (smart trainer measured power) and outdoor workouts (power meter).

    • Henri,

      Great comment regarding 4iiii’s scale factor. I was a former Stages left-side only user and it always seemed that my power output was too low compared with my performance. I switched to Assioma dual-sided pedals 2 years ago and of course they proved that my left leg was the weaker one, thus under-reporting my power.

      But here’s where it gets interesting. You state that leg imbalance is quite consistent for a person. In my case, I have found the the disparity between legs increases with effort. Typically for moderate efforts I am L/R 46/54. If it stayed that way across all efforts I could shrug it off. But for light efforts I am at 48/52, or even 50/50 if I focus on my form. But at the other extreme, I did 10 minute efforts at threshold earlier this year and my balance was a disturbing 41/59. My data over the course of the last few years proves this again and again: the harder I go, the greater the disparity. So I am wondering if anyone else with dual-sided power has experienced this, or whether it should be addressed. (Bike fit? More strengthening of the left leg?)

      Steve, thanks so much for another extraordinarily researched and informative post! I really appreciate it.

      Also to add 3 more advantages of dual-side power meters:
      1. Can do single-leg drills on the trainer. (Stages not only would not record, but would pause the workout. Pedaling right leg only was as if I had stopping pedaling)
      2. More accurate for shorter efforts, since there is twice the data for a given time. Useful for sprinting.
      3. If you are competing on Zwift, your power/weight ratio will be more accurate (if you have a significant leg disparity)

  • Hi Steve,

    Interesting read, I very much appreciate your sorting all this out. WRT buying & using a PM, I’ve been resisting while many biking friends push me (gently) to get a PM setup. Perhaps not your intention, but just having this of setting the zeroing meter before every ride convinces me not too bother. Getting out for a ride is already complex enough. Anyway, like many riders, especially us older guys, I carry about 15# extra weight & nothing I could do training wise would make as much difference as dropping the weight, so that too.


    BTW, there are a number of typos in the article. For instance, “…about 5 years of all this new product…” which I assume was intended to read “…about 5 years after all this new product…”. No biggie to me. But if you’d like, I’ll send you a few other edits as well.

    • Ron, If it makes you feel better, Favero and Quarq have updated their firmware so that once set, you don’t need to zero offset unless you transfer the power meter. And, my personal experience as an old guy is that a power meter, training, and weight loss make up a virtuous triangle. Using a power meter made my training easier/better and caused me to lose weight.

      And yes, I’d welcome your input on typos and edits. (send to:[email protected]). My eyes get a bit glassy after writing, reading, editing, over and over as I put these reviews together over weeks to the point where I can’t see it anymore. Thanks! Steve

    • Ron,
      I built up a bike last summer and bought a Quarq Dfour spider power meter and it works great. Best feature, no calibration or zero-offset required before you ride. Problem solved!

  • What about IQ2?
    Did I miss seeing it?

    • Andre, IQ2 is a current example of a power meter that, like many that never made it during the boom years, was announced, redesigned a year later (from a crank arm to a Look KEO pedal power meter), has missed shipping date goals, is not yet in production, has not had production units independently tested on the road for performance and reliability, but sounds terrific if it ever delivers as marketed and priced.

      Check back in a year. They may or may not be able to deliver on what they are working on. Unfortunately, too few companies new to power meters have been able to do so. Steve

  • Brilliantly clear article – quick question. My road bikes are all Ultegra and gravel bikes Shimano 105. If I were to buy an Ultegra model of either the Stages or 4iiii left crank power meters is there an issue switching between the Ultegra and 105 cranksets?

    • David, nope, none at all. I’ve transferred a left Shimano power crank arms among Ultegra, 105 and GRX cranksets. The Shimano crank fittings are all the same. Steve

  • Do all the options support using their own proprietary head unit or sending the data to a smart phone? I’m trying to figure out the best way to consolidate the visualization of data while riding.

    • Whitman, none of the six I’ve reviewed use proprietary head units. Use standard cycling GPS head units that read ANT+ and BLE like one of these from Garmin or Wahoo. And while some recreational riders do, you really don’t want to put your smartphone on your bars (too big, not crashworthy, battery hog, not purpose-built, need apps, limited functionality, etc.). Steve

  • Hi. Really enjoyed the article – informative, detailed and (mostly) fact-based. Nevertheless, a couple bones to pick with regards to the non-factual bits:

    1) you wrote: “More roadies bought these new and lower-priced established models and learned how to use them to improve their performance without the need for a coach”. IMHO power-meters don’t render coaches unecessary (and I’m not one). If anything, coaches are even more necessary, given the diferent metrics that now come into play (TSS, ATL, CTL, IF, etc). Not having a coach – or a very deep understanding of how to use these metrics when drawing a training plan in their absence – may mean that the power meter istelf will end up being used as the most expensive speedometer in the world.

    2) I would add “Customer Service” as one of the key components when deciding which power-meter to go for. To be fair, this is not something that you alone left out of the equation. I almost never see it on reviews. And yet, no rider wants to be left waiting months on end for the issue(s) with his power-meter to be dealt with (and all of them have their issues).

    Still, as said before, great overall job.

    • Maximilian, Thanks for your kind and constructive feedback.

      Regarding coaches, I agree that power meters don’t render them unnecessary. It’s more like coaches aren’t absolutely necessary to do good training as they were before. Now, if you’ve got a training plan or subscription from one of the better services and Training Peaks to track your progress, you can use a power meter to follow the plan guided by all the metrics you mention. Yes, the plans are written by coaches but they don’t require you to have them on retainer and customize the program for you. Certainly better if you can afford it, but not necessary. I write about this in the Acceptance has been realized section further down. Reading the Hunter Allen and Andy Coggan book that I mention in that section will also tell you all about those metrics.

      On customer service, I agree with you. I haven’t researched this rigorously and wish I could for all the products I review. Reading through comments on forums and at the end of other reviews and talking with a few retailers about their experience with some of these power meters didn’t pop up persistent reliability issues or an unusually high return rate beyond (beyond the Garmin pedals which I cautioned against) or customer service complaints. I know, not the best way to measure this but that’s about all that’s available unless I did a more rigorous study.

      3-4 years ago, this was a bigger problem with the power meters. All six of the ones I’ve reviewed here have been around long enough to have resolved prior issues (e.g. Stages battery doors) they may have had with product iterations (except Garmin). If there were still reliability or service issues, I think we’d be hearing about it. Some that couldn’t resolve their issues have left the business for this very reason. Cheers, Steve

      • Maximilian Leisner

        Thanks Steve. I have not only read Hunter’s book, but also attended one of his camps in the US and promoted two others :-). This one still is, as you mention, the go to book for anyone interested in learning more about power meter and all the metrics involved. My comment regarding the need for a coach is that, based on the athletes I have been around (i.e. have sold units to and/or trained with), those who elect to forego the coach end up looking at the numbers on the computer’s screen as if the readings alone would make them perform better. But you are right about the online coaching platforms. They help bridge the gap, so to speak. Cheers.

  • Hey Steve
    Great article! I want to buy a power meter and crank arm type looks best for me, but I have a Cannondale SuperSix Evo with a cannondale crankset (the rest of the components are Dura-Ace). Do you know if these crank arm meters will work with a Cannondale crankset? Don’t do any research for me. Just wondering if you know.
    Thanks much

  • Hi Steve,

    I’m a big fan of your work! I learned a lot from your articles, especially on rims and tyres. Am waiting for my 50mm (24mm inner width, hooked) gravel wheels to be delivered from Farsports I ordered with help of your articles.

    I really want to take training a step further then the HR zones related training I’ve done over the last few years. Read Friels’ bible and love it.

    I ride a 2019 Trek Checkpoint SL6 Di2 with the Ultegra R8000 groupset. The Checkpoint has no room for a left crankarm based PM, I ride mtb spd pedals so basicly the only option (if I want to keep the slick Shimano crank looks) is to go for right arm only PM. I like the 4iiii and don’t care to much about the exact measurements as it is for my training only. But I do want and need consistency in the measurements

    That’s where things might go wrong…. there seems to be a significant problem with PM on the right crank arm with (only) the Shimano Ultegra and Dura Ace models.
    Your work is always super in depth so I am surprised not reading anything in your article about these issues. Or did I just miss it?

    The whole issue is explained in great detail by GP Lama (link below). I am very curious about your opinion about this!

    I hope you find time to answer this soon as I am about to send my crank from The Netherlands for a ‘cosmetic surgery holiday’ to Canada ?

    And keep up the great work with the wonderful reviews you guys are making!! ??



    • Paul, Thanks for your comment. First, I have never reviewed and do not recommend Farsports gravel or road wheels.

      As to the power meter, I am familiar with the GP Lama report that you site. This report broke some new ground in their testing approach and findings. Other independent reviewers using different protocols didn’t find similar issues with the Stages and 4iiii power meters they had tested. More recently (as in since I first published this review), Ray at DC Rainmaker reported a similar issue with the 4iiii model but has been less than definitive about the Stages right. Whatever is causing the issue, it seems to be confined to the right side only of the latest 8000 Ultegra and 9100 Dura Ace models. So I’ve now updated my review to recommend the left side only power meters for those who have Shimano cranksets. I’ve not seen anything about the 105 and GRX right side power meters but I’d err on the side of caution and recommend against their right side power meters as well. I’ve always recommended most enthusiasts only need a left side power meter anyway.

      For your situation where you can’t fit a left-side power meter and use MTB SPD pedals, you’ve probably seen that Garmin has introduced the Rally XC100 and XC200 MTB SPD power meter pedals. They are pricey and I’ve just now gotten a pair to begin testing, but that’s an option. SRM makes one as well but it’s even more expensive and the jury is still out on their performance. Another option would be to go with the left side Favero Assioma Uno pedals and buy yourself a good pair of road shoes. You’d still come out ahead after buying the shoes. 🙂 Steve

      • Hi Steve,

        Thank you for your fast reply!

        I never intended to suggest you recommended Farsports wheels. Your articles about all the different aspects of a carbon wheelset really helped me make my own decision. I just wanted to share the outcome of that decision, just fyi.

        Thx for the tip on the Garmin new pedals, I was not aware! Way out of budget though, I considered buying vector 3’s with the RC kit but no go either.

        I am trying to get some quantification on how bad the ‘4iiii right only’ option would be for my training, am just an amateur enthousiast who rides apr. 200km/week and a few cyclos each year.

        If the 4i option means my measurements will be within a 5-10% variation I think the influence on my actual training would be neglectable.

        The video off the former 4i/Garmin PM engineer on the GP Lama site suggests the variations could run up and over 25% theoretically, that’s kinda scary but (hopefully) not very likely…

        I’ll dive some more into it, thanks for your help!

  • Steve, long time reader and user of your reviews. Your testing and research convinced me to go tubeless on my BMC Roadmachine. I also followed your lead and upgraded to the ENVE 3.4 AR wheelset. I am now in the process of buying my first gravel bike and following your lead with a Giant Revolt. Although speced with GRX the crankset is a Praxis. My road bike has a Stages LH power meter (Ultegra crankset) which is very reliable. Stages does not offer a power meter for Praxis cranksets. Did you swap out your crankset for a GRX to accommodate a Stages? There are other options (pedals or spider based) but all have long backorders. Thanks for all you do. Joe

    • Joe,

      Thanks for your confidence in my recommendations. Glad they’ve worked out. Feel free to support our ability to keep doing what we do by buying through the links on the site.

      I did get a GRX crankset to replace the Praxis on my Revolt and then put a 4iiii left side 105 crank arm on it as my groupset is a 105 as well. But you can get a power meter installed on your GRX 810 crankarm through the factory install programs with a pretty quick turnaround. Power Meter City can set you up for Stages through this link and 4iiii through this one. They also offer In The Know Cycling readers a 10% discount on 4iiii. Use the code ITKPMC10 at the checkout screen. Steve

  • I may have missed it in your review but do you cover whether or not the Quarq power meter will allow a cycling computer to display torque effectiveness and pedal smoothness? I’m in the process of buying a new bike and the shop recommended going with the Quarq spider on with cranks and bottom bracket on an Ultegra Di2 bike, it seems like a big expense with little to no upside compared to a single crank arm pm or even a downgrade if these data fields are not available. I have the left crank arm pm from Stages on my current bike and those data fields are great motivators in keeping my pedal stroke smooth and consistent.

    • Steve, a few reactions. 1) you may have misheard what your shop told you or the shop salesperson doesn’t really understand power meters but the Quarq bolts to the chainrings not the cranks or bottom bracket, 2) torque effectiveness and pedal smoothness may motivate you but they are rather worthless metrics and have not shown to have any correlation with power output. These metrics were created by Garmin to help market the Vector power meter pedals. 3) With a left-only power meter, you’re only measuring these metrics for your left side. 4) Quarq power meters don’t provide these metrics. Favero and Garmin power meters (both pedal power meters) do. 5) I’d suggest you focus on your watts as the primary metric and the only one that really matters to going faster. Better on-bike training, weight lifting, nutrition and sleep will improve your power output as measured by your watts. The other Garmin metrics like L/R balance, the two you mentioned, and the others in their analytics package don’t correlate to your power output. It’s good marketing but has no performance effect.

      Bottom line, I’d suggest you move your Stages left crank to your new bike and avoided the bike shop upsell attempt. Steve

      • Thank you for the fast response. The bike I’m buying comes with Ultegra Di2 so if I went to the Quarq power meter I would have to also buy the crank arms and the DUB bottom bracket, definitely not what I was planning and the more I think of it the worse it sounds. I actually do use power output as my main focus but those other fields just made me aware of how inconsistent my pedaling had been, if nothing else it motivates me to put out more power as my torque effectiveness tends to increase along with power. I was considering sending the new cranks to 4iiii to have sensors installed on both sides but apparently that would also be a waste, I would love to have the data on both of my legs but as you mentioned there is no genuine benefit or way to ensure accuracy unless I go with pedals. Thanks again, looks like I’ll be sticking with the left crank arm.

  • Great review and great web site in general – I feel like I discovered a gem, and very much appreciate the analytical and no-nonsense description of what is going on across the board.

    I have an older bike, a 2003 Trek Fx 7700, and can’t find any information on compatibility with the crank-based power meters, any idea how I would go about figuring out if I can install one of them?

  • Yiannis, Welcome and thanks for your kind feedback. Depends what kind of crankset you have. That bike originally came with a Shimano Deore XT groupset though I’m not sure what crankset you have on your bike now. You give Power Meter City a call and ask Josh (tell him I said hello!) if one of the modern left-arm Shimano cranksets will fit on your bike. Otherwise, go with power meter pedals with the sensor only on one side. Those will fit any crankset. Steve

    • Hi steve, thanks a lot for your excellent review, i use power tap pedals in one of my bikes and AXS power meter in the other one, the average power bettween them are 20 watts, i think that is really a big difference, do you think there is a problem with one of them? Or this difference can be normal.

      • Juan, I assume you put the Powertap pedals on the bike with the AXS and did a 30min or longer test to determine this difference? If they were both calibrated and this wasn’t a short segment spike difference then clearly there is a problem with one of them. SRAM bought Powertap and while they don’t make those pedals anymore, they may still service them. And of course, SRAM’s Quarq division makes the AXS. I’d put a call into SRAM or a SRAM dealer and see if they can help you figure out which one needs to be fixed. Steve

  • There is so much comprehensive information here and the fact that there are discount codes is just icing on the cake!

    I just ordered a 4iiii left sided pm from Power Meter City.

    Thank you

  • Hi Steve, very informative and helpful in narrowing the options down. Thanks.

    The left side 105 crank arm power meter seems a good option, however I am concerned that there may not be enough clearance between the sensor and the stay on my new Trek Domane. In your experience, do the height profiles differ between the 4iiii and Stages? Have you heard of any such fitting issues?

    The reason for my concern is that I found I was unable to mount the wahoo cadence sensor on my crank arm, because of inadequate clearance, and ultimately had to attach it to my shoe laces.

    • Jim, the latest models of the 4iiii crank arms have sensors that are a good deal thinner than the Wahoo cadence sensor.

      Per this article from Josh Matthew who runs one of my recommended stores Power Meter City, “the 4iiii PRECISION 3 uses a new, slim sensor that is only about 5 mm thick. This means, you only need close to 7 mm of total clearance with the PRECISION 3 (vs. 10 mm for the Stages). This renders most incompatibility issues a thing of the past.”

      I can’t say for sure but I’d expect the new 4iiii should fit on a relatively new bike like the Trek Domane if you’ve got the 7mm or so of clearance that Josh describes. Steve

      • have you tested out the new generation? i’ve heard it isn’t as reliable as the 2nd gen. i want to buy it but with the dropouts, laggy/jittery data in cadence and power makes me wonder how accurate it really is. any experience? i want to get this on my grx left side crankarm. just skeptical with few reviews and mostly negative.

        • Jonathan. I haven’t. Not sure what you’ve heard or where you’ve heard it from. The test results I’ve seen from GPLama shouldn’t bother you unless you are a high level track athlete that cares about 1 second delays – the segment power numbers for the units he compared the latest gen 4iiii to are well within the claimed accuracy range. And the review that included testing from VeloNews done by Ben Delaney whose been doing this kind of testing for years in a way that’s relevant for amateur racers and the rest of us didn’t have any issues with the unit. If I’m missing negative reviews, please send the links to me at [email protected] and I’ll look at them and let you know what I think. Steve

          • hi steve, thanks for the reply. yes i saw GPLama’s recent review. i didn’t want to purchase this until i saw either his review or DCrainmaker. sorry when i meant mostly negative, i saw some on reddit, 4iiii’s facebook and the comments on GP’s youtube comments. they said they’d stick with gen 2, no reason to upgrade. it’s like a step backward being it gen 3. i’m not a high level cyclist but i do love numbers/data and have my power set at instant power or 1 sec updates. i have the power tap p1 pedals and very happy with those. maybe i’m overthinking but after seeing the comparison’s it kind of turned me off if you know what i mean.

  • Jonathan. I agree no reason to upgrade from either the 4iiii Gen 2 or Powertap pedals if they are providing you consistent power readings that help you train. GPLama’s power meter reviews can be a bit overly sensitive to things that don’t really matter for most cyclists. Comments on forums can be from people who have limited experience comparing different units or using a robust testing protocol. For the most part, power meters are mature technology whose accuracy and consistency serve most everyone’s training needs. Power meter location, features, and price separate them now.

    I’m also a bit geeky when it comes to numbers and data but from a training standpoint, I’d suggest that focusing on average power readings less than 3 or 5 secs can add a great deal of “cognitive load” without adding any training benefit. Best, Steve

    • thanks steve! really appreciate it, gives me peace of mind. the reason i consider 4iiii is for the low profile to fit my future gravel bike and enough clearance for mud as well. i may consider gen 2 if there is enough clearance too. i have shimano xtr pedals so i won’t need the powertap pedals. i considered the garmin xc100/200 but very expensive and pedal strikes from higher stack is a concern. would be really awesome if favero made mountain bike spd compatible pedals. seems affordable and reliable.

  • I’ve only just stumbled across this site and am loving it.

    Thought I’d share my take on single sided to dual sided power meters. For years I rode with a single sided 4iiii and was happy with it, however the bike that was on got stolen and when I replaced it I decided to try a pedal based system and went for the Favero.

    What I found was my imbalance varies depending on how much power/ which training zone I’m in. This can have quite a big difference when I am trying to hit certain zones. If my imbalance was consistent there are tools within the 4iiii to correct the numbers but because of the drift in balance as I put out more effort they become less and less accurate.

  • Steve

    Thanks for your very informative power meter reviews. I just purchased a Parlee RZ7 with a Dura Ace DI2 11 speed group. The Dura Ace Crankset is equipped with Specialized dual power meter. Based on yours and many other comments regarding right side accuracy issues with Dura Ace cranks and being one size longer than my 170mm preference I will be changing to a Dura Ace left side only power meter. Based on all of your research and testing is Stages or 4iiii the better option?

    Thank you

    • Tracy, I haven’t seen any data that suggests they report differently. 4iiii just introduced connectivity with Apple’s “Find Me” tracking software so that’s a nice plus. Otherwise, I’d shop around to see if there’s a better deal on one vs. the other going on now with the Labor Day weekend sales in place. You might even want to consider selling your DA crankset with the power meter and get a DA (or Ultegra) crankset w/o a power meter but in your preferred size and then send the left arm to 4iiii or Stages to have them mount the power meter sensor on it. Cheers, Steve

      • Steve

        Thanks for your quick response. I am planning on selling the Dura Ace/Specialized crankset as it is one size too large and buying a DA 170mm and sending the left arm to either Stages or 4iiii for PM installation. I just wanted to see if your had a preference based on all of your research.

        BTW- I really appreciate all of the well researched articles you and your team are providing an have based several buying decisions on your recommendations. Keep up the great work.

        • No technical preference but If you put the order through my link to Power Meter City and use our exclusive code you can get 10% off and you support the site at the same time.

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