In The Know Cycling

If you regularly ride steep, long climbs, you should consider getting the best lightweight wheels or climbing wheels you can find.

The best lightweight wheels for climbing are stiff, aerodynamic, comfortable, and light. Those characteristics will help you convert your power and hard work as efficiently as possible going up while confidently handling the high speeds and frequent cornering coming down.

But there are dedicated climbing wheels and wheels that climb and perform well on a range of terrain and surfaces.

In this post, I’ll share with you the kind of riding I believe best suits climbing wheels, what matters most when choosing lightweight wheels, and our reviews of those we’ve tested from some of the leading wheelmakers.

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BEST PERFORMER – ZIPP 353 NSW

Despite a depth that suggests it is an all-around wheelset, the Zipp 353 NSW wheelset doesn’t carry the momentum that the best all-around wheels do and climbs and descends nearly as well as the best, dedicated climbing wheels. It also performs well on everything from smooth paved roads to rough gravel ones.

Indeed, versatility is one of its greatest strengths.

At 1248 to 1268 grams, depending on the hubset you specify, the 353 NSW is almost freakishly light for a non-tubular wheelset of its depth and width. It’s 150 to 200 grams lighter than most of the current generation of tubeless disc carbon wheelsets and only about 100 grams heavier than the lightest, pure climbing ones.

It’s stiff, handles extremely well, and is supremely comfortable.

The Zipp 353 NSW is also one of the most expensive wheelsets you can buy at US$4220/£3376/€3798. If you’re so inclined, you can order it at recommended stores Competitive Cyclist, BTD (BikeTiresDirect), Merlin, and Sigma Sports.

You can read my full review here.

BEST PERFORMANCE-PRICE COMBINATION – ZIPP 303 FIRECREST DISC

Nearly equal to the performance of the pure climbing wheels from ENVE and Bontrager in this review, the Zipp 303 Firecrest at US$2046, £1780, €1994 is a relative value for paved road climbing and gravel road riding.

Shallower (40mm), wider (25mm internal, 30mm external), and lighter (1383 grams) than the prior 303 Firecrest Disc model, it is more climbing oriented than any of the long line of all-around rim or disc brake Firecrests that Zipp built its brand around.

While also stiffer than earlier Firecrests, it’s not quite as responsive, comfortable, or fast as the similarly dimensioned ENVE SES 3.4 or Bontrager Aeolus RSL 37V on climbs, paved flats, or gravel. But, this Zipp offers a price the others don’t come close to for the level of performance you get.

You can order it through these links to recommended stores Competitive Cyclist, BTD (BikeTiresDirect), Merlin, and Sigma Sports.

You can read my full review here.

WHAT YOU NEED TO KNOW ABOUT THE LIGHTWEIGHT WHEELS

Click on any red statement below to go directly to that part of the post

Who climbing wheels are best for

What matters most in deciding between lightweight wheels

Reviews of lightweight wheels best-suited for climbing

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WHO CLIMBING WHEELS ARE BEST FOR

Climbing wheels are for riders who do long rides that are centered on climbing up and going down 7% and steeper pitches that go on for kilometers or miles at a time.

I don’t mean those of us who regularly ride “rollers,” those 4-5%, half-kilometer or quarter-mile hills that might total 5 km or miles during the course of a 40 to 75 km or mile ride. Or even those rides that might include a half km or even a half-mile climb that averages 7% during your ride.

You could certainly ride lightweight wheels on those kinds of rides to give you some advantage going up steeper sections. But you must ask yourself whether what you gain on the hills with climbing or lightweight wheels is worth what you lose on the flatter sections and downhills when you don’t ride more aero, all-around ones.

My experience? I really miss the deeper wheelset on the flats and going down the rollers when I’m riding climbing wheels or any lower profile wheelset on all but the steepest climbs and long rides.

For example, I did a 125 mile/200 km long ride with 8500 feet/2600 meters of climbing on a set of 25mm deep, 1350 gram lightweight wheels that included two steep, long, tough alpine climbs that exceeded 12% on average. The wheels were great on those climbs, the best I had ridden from that model year, but I think I worked just as hard, if not harder keeping up with the group on the far more frequent flat and rolling sections because I didn’t have deeper wheels.

Several months later, I did a steeper, shorter route, a 100 mile/160 km ride with about 11,000 feet/3350 meters of climbing on a 1425 gram, 33mm deep set of wheels. It seemed that I was always climbing or going downhill on that ride. I’m glad I was riding those wheels.

As all-around disc brake wheels have entered their 4th generation, they are getting lighter and deeper. Several that are now 45-50mm deep weigh between 1400 and 1500 grams. With a deeper carbon rim, they tend to be stiffer and transfer your power better than shallower, lighter ones do.

The best lightweight wheels for climbing have themselves become deeper, some now close to 40mm, whereas several years ago, most were in the low 30mm range.

To set themselves apart, or at least to notice a performance difference compared to the latest all-around wheels, today’s climbing wheels need to be 100 to 150 grams lighter than those all-arounders while being deep enough to feel essentially as stiff.

Where I ride and even when I do all but the steepest routes with 1,000 feet or more of elevation every 10 miles of riding (300 meters per 15 kilometers), all-around road disc wheels are the way to go. I’ve reviewed the best of those wheels here.

If you do a lot of riding in the mountains, yeah, you’ll want wheels designed for climbing.

If, on the other hand, I lived at the foot of or regularly visited the Rockies, Sierras, Pyrenees, Alps, etc., I’d definitely want to be able to put a set of lightweight wheels for climbing on my bike for those days when I’m doing those steep, long alpine climbs and descents.

Descending is not often considered when choosing climbing wheels. But, to do it fast and safely, aero and crosswind performance, stiffness, comfort, and handling are key to enjoying the ride downhill that you earned working so hard going uphill.

Of course, you could always have a support vehicle follow you and quickly change your climbing wheels when you hit the big mountains and switch back when you get off them.

What? Are your friends or partner not into that? Mine either.

Regardless, climbing wheels are also for those of you with deep pockets. Dedicated wheels for climbing may be the third or fourth wheelset in your quiver. You may still have stock wheels that came with your bike or another alloy set for all-weather training. You may also have all-around or aero wheels (or both) for most of your training, group riding, road racing, or TT riding. Maybe a gravel wheelset or some MTB wheels for off-road adventures.

We’re seeing more and more all-road wheels available that climb and descend well on well-paved, poorly-paved, and gravel roads. Some are nearly as good on steep pitches as pure climbers, and their versatility can serve you well, even though they’re not as fast as the best all-around wheels on and off-road. I’ve included the best climbing all-road wheels in this review.

As most of the best climbing wheels cost at least $2000/£1500/€2000 and many run half again more, it’s not a purchase for those trying to stick to a cycling budget. Lucky you!

LIGHTWEIGHT WHEELS SELECTION CRITERIA

If you believe weight is the primary benefit of riding a dedicated climbing wheelset, is that the primary criterion for choosing between them?  Far from it.

When I evaluate wheels, I look at four groups of selection criteria and about 20 specific ones within those groups.

Immediately below, I’ve highlighted the relative importance of those criteria for wheels you’ll want on long, steep climbs and descents vs those for all-around and deeper aero wheels.

As you can see from the criteria I’ve emphasized for picking wheels for the mountains, half of them – aerodynamics, compliance, braking, and rim profile – are not criteria you would consider in choosing what has been traditionally considered a ‘climbing wheelset’.  These are important characteristics to ride fast and confidently on the high-speed, steep descents you’ll experience going down a long mountain pass.

In these situations, you’ll want aerodynamic wheels for max speed with rim profiles that keep the bike stable in crosswinds. While most dedicated lightweight wheels for climbing are lower profile than all-arounds, you can still shape the rims to reduce drag and cheat the crosswinds.

You’ll also want compliant wheels going down often rough alpine roads and handle well as you are whipping through the switchbacks. If you are riding rim brake wheels, you’ll want to be able to brake reliably at high downhill speeds and in all weather conditions. You don’t want any fading or degradation in braking on long descents. While this was more important for alloy and carbon rim brake wheels, disc brake rotors on road disc wheels must be aligned well with disc brake calipers and supported by good hydraulic brake systems to make it all work.

For climbing, you might as well take advantage of lightweight wheels, but you also want ones that transfer your energy into power as effectively as possible. That’s why stiffness is emphasized. When you are cranking out 250-400 watts trying to keep upright going up pitches ranging from 7% to 15% for what seems like forever, you want stiff wheels to convert your effort as efficiently as possible to the road.

As I hope you can see, you have different and equally important needs going up and down a long, steep mountain road, and weight is only one of many considerations. That’s why I think “climbing wheels” is a misnomer. Instead, you should consider these as both climbing and descending wheels or lightweight wheels that must perform well in both directions.

Finding wheels that accomplish all of this requires some trade-offs. Very light wheels aren’t usually the stiffest, for example. And aerodynamic wheels to some mean deep dish rims, which aren’t usually the best at handling on windy mountain descents.

There are also some things that you really don’t want to compromise on. Older carbon clinchers have no place on long downhills where you need to do a lot of braking as they can overheat, warp, ruin the wheels, and result in a blowout at speed. I no longer included rim brake wheels in this review as they are generally inferior to disc brake ones.

At the same, you don’t drag your brakes and overheat or warp your rotors.

The heavier you are, the more these criteria matter. You’ll put more energy into the bike going up and will travel at higher speeds and create more braking energy going down. A rider weighing 190lbs or 200lbs or more will want a stiffer wheelset than a 150lb rider with the same watts per kilogram. They will also need more room to brake.

On the other hand, the lighter rider will be more prone to getting pushed around on a windy descent if the wheel’s profile doesn’t handle crosswinds well and will benefit more from an aerodynamic profile that cuts through both crosswinds and the apparent wind created going down a mountain. None of the wheels in this review here are so deep or have rim profiles that cause a big problem, but some are shaped better than others to have no problem except in the strongest winds.

Looking to the pro racing circuit for guidance on climbing and descending wheels is a mistake. The best climbers typically weigh 135 to 145 lbs, have 6% or less body fat, often ride super-light, super-stiff bikes, and put out more than 5 watts/kilo going uphill during a race. They also have support vehicles to give them different wheels or bikes during the race, depending on the terrain.

I’d guess most road cycling enthusiasts have 15-20% body fat (the amount for a “fit body type”), climb at 3 to 4 watts/kilo, and often ride comfortable endurance bikes rather than super stiff or super light race bikes. Sorry to say, the pros and we amateurs live in two different worlds.

Even those of you lighter men and women with natural climber body types, <10% body fat, 4+ w/kg ratios, and on very stiff racing bikes will still finish 10-20% (3-6 minutes on an hour ride) behind pro-level racers on the most challenging climbs. You can draw on lessons from the pros, but buying the same wheels they ride, hoping to get a far better result, is not likely.

If we could buy their genetics, we’d have a better shot.

So with all that as background, let me share with you my evaluation of the best lightweight road disc climbing wheels I’ve tested. If you’re looking for rim brake wheels, I’ve recommended the best for climbing and other categories in this review.

REVIEWS OF LIGHTWEIGHT DISC BRAKE WHEELS FOR CLIMBING

Best Performer

ZIPP 353 NSW – VERSATILITY TO A FAULT

Despite a depth that suggests it is an all-around wheelset, the Zipp 353 NSW wheelset doesn’t carry the momentum that the best all-around wheels do and climbs and descends nearly as well as the best, dedicated climbing wheels. It also performs well on everything from smooth paved roads to rough gravel ones.

Indeed, versatility is one of its greatest strengths.

At 1248 to 1268 grams, depending on the hubset you specify, the 353 NSW is almost freakishly light for a non-tubular wheelset of its depth and width. It’s 150 to 200 grams lighter than most of the current generation of tubeless disc carbon wheelsets and only about 100 grams heavier than the lightest, pure climbing ones.

It’s stiff, handles extremely well, and is supremely comfortable.

And boy, does it climb! I almost had to check that I hadn’t left my water bottle or saddle bag at home when I hit the hill a quarter-mile from my house the first time out.

Miles blew away the competition when he rode the 353 NSW in the Crank the Kanc race with a 5-mile, 7% uphill finish. Since the race starts with a 10-mile 1-2% grade, he put these Zipps on his Giant Propel aero bike. It turned that bike into a legitimate climber. That’s versatility for you.

We didn’t experience any effects of crosswinds riding the Zipp 353 NSW on flat and downhill terrain. While its rims have the sawtooth pattern designed to neutralize them on their deeper 454 NSW, crosswinds haven’t been an issue with the last couple of generations of Zipp mid-depth wheelsets we’ve tested. Even Zipp told me they used the sawtooth design on the 353 NSW principally to reduce weight.

Tracking in turns, making quick direction changes, and doing other handling maneuvers on both good and rough roads with these Zipps produces a confident thrill unmatched by most wheelsets.

And comfortable? You bet. Nate described them as “plush over bumps at high speeds.” Miles called them “fantastic, so comfortable cruising over imperfections.” I concur.

With its inside hookless rim width I measured at 25.5mm, we rode the 353 NSW with 28mm Schwalbe Pro One TLE during our test rides between 55 and 60 psi. I measured these tires, and the 28mm Specialized S-Works Turbo and Bontrager R3 Hard-Case Lite are all narrower than the rim. That will give you reduced aero drag at high speeds.

Yet, these Zipp 353 NSWs aren’t aero stars. All of us noted that you’ve got to keep the pressure on the pedals to keep your speeds up.

I rode the 353 NSW back to back on the same day and on the same route against the Zipp 303 NSW that it replaced. The 303 NSW was clearly superior in my ability to hold speed or momentum. I’m not sure why – likely because the 303 NSW is a 250-gram heavier wheelset, only a touch deeper than the undulating 42-46 mm deep 353 NSW and with an earlier generation of the smooth-flowing Cognition hub – but I noticed a big difference.

We had split opinions on the stiffness of the 353 NSW. Nate, one of the strongest age-group climbers in the region, was “underwhelmed by their stiffness”. He found them sluggish on short, punchy climbs. On the other hand, he thought the rear hub engaged more rapidly than the many other wheelsets he’s tested.

Miles, no slouch when it comes to climbing and only a few kgs lighter than Nate, thought these Zipps were “incredibly stiff,” but engagement felt average, especially when he accelerated on the steepest gradients during his hill training. Once engaged, however, he loved the way they accelerated.

To-mA-to, To-mAH-to? Hard to know.

I’ve now done a few gravel events on the 353 NSW. As expected, the comfort, handling, and climbing ability we’ve enjoyed on the road translates well off of it.

While the Zipp 353 NSW is clearly a standout climber and would likely perform with the best of them on gravel, it’s not as fast against other all-arounders. It’s almost as if its versatility works against it, especially when trying to justify the US$4220/£3376/€3798 price tag.

But if what it does well is the combination of things you are looking for, you can pick it up at Competitive Cyclist, BTD (BikeTiresDirect), Merlin, and Sigma Sports.

Best Value

ZIPP 303 FIRECREST DISC – VERSATILE VALUE FOR GRAVEL AND ROAD CLIMBING 

I’ll admit to being a bit skeptical of the new Zipp 303 Firecrest Carbon Tubeless Disc Brake wheelset before I rode it.

I’d learned to love the unique combination of comfort and speed of the 303 NSW disc road wheels that Zipp sadly dropped from their line-up after introducing this new Firecrest. And the also new, low-priced 303 S (reviewed here) I tested before the Firecrest didn’t ride like any Zipp wheelset I’ve ever known.

So while I wasn’t sure what to expect, I feared that Zipp and their new, more jagged-looking logo might still find their way with this successor to the Firecrest franchise.

After riding this 303 Firecrest disc wheelset on enough paved flats, rollers, alpine climbs, and a full range of gravel surfaces to get a bead on its character, I can tell you it is blazing a new Firecrest path.

And, for what it costs and what it does, I like that path.

At UUS$2046, £1780, €1994 for a Firecrest, that path starts at a low price. With the $3200 Zipp 303 NSW disc that replaced the earlier $3200 303 Firecrest both now out of production (the $4000+ Zipp 353 NSW and 454 NSW replacing them), that is the lowest it’s been for a Firecrest in, I think, ever.

Add to that, the 303 Firecrest disc is far wider (24.9mm inside, 30.0mm outside per my measurements), far lighter (1383 grams including pre-taped rims), and somewhat shallower (40.4mm) than previous Firecrests. Oh, and it only takes tubeless tires and has hookless rims.

So all that’s part of the new path that Zipp claims “is designed for the real world… a world of imperfect conditions, road surfaces, and elements”. Simply put, it’s intended to be ridden on both paved and gravel roads.

For the most part, the Zipp 303 Firecrest disc pulls it off.

As a gravel bike wheelset, the 303 Firecrest is the full package. It’s comfortable and confident, or at least makes me feel that way on any class surface. Negotiating around rocks, ruts, branches, and in and out of lines, this wheelset is nimble and responsive.

Stiffness is a plus on these 303 Firecrests. Notably, stiffness wasn’t always a characteristic strength on previous Firecrests and isn’t on other Zipp wheels if you are a heavy rider or putting a lot of watts into them. This greater stiffness also shows up on gravel climbs, where the new 303 Firecrest disc excels.

The hubs also perform well on unpaved roads. They engage relatively quickly and provide the acceleration you frequently depend on riding gravel roads with their regularly changing pitches and surfaces.

Zipp uses their own ZR1 hubset on this Firecrest, a 6-pawl, 6 degrees of engagement affair. This is also a new model for them, something they seem to do with hubs every few years regularly. Because of that, it’s frustratingly hard to know how they’ll hold up over time.

On paved alpine climbs, I found the 303 Firecrest Zipp nearly as good as the best lightweight disc wheels like the ENVE SES 3.4 and Bontrager Aeolus 37 RSL (reviewed below). It wasn’t as snappy as the ENVEs or as quick as the Bontrager, but it was steady, strong, and felt like nearly every watt of power I put into the wheels went right to the road.

At a measured 1383 grams with the Shimano/SRAM 10/11-speed compatible HG freehub on the wheelset I tested, its light weight (about 30 grams heavier than the Bontrager and 40-50 grams lighter than the ENVEs) clearly makes it one you’d want to join you going up long, steep climbs.

On flatter paved roads and rollers, some differences between the Zipp 303 Firecrest disc and the more expensive ENVE 3.4, Bontrager Aeolus RSL 37Vs, and Zipp 353 NSW came out. The ENVE, Bontrager, and NSW are more comfortable and roll smoother on paved roads.

On paved roads, I used Zipp’s Tangente Speed Road Tubeless tires. While they’re no longer in production, I’ve found them among the best tubeless tires. I did A-B and A-B-C comparative testing of the ENVE SES 3.4, Zipp 303 NSW, and Zipp 303 Firecrest. The Firecrest and ENVE 3.4 with their 25mm internal width rims got 28mm Tangentes inflated to the same pressure, while the 21mm internal rim width 303 NSW was shod with 25mm Tangentes inflated to the appropriate pressure for their widths and my weight.

Each of these wheelsets uses different hubs and layups. That might explain the comfort differences.

While I don’t expect top-end aero performance from a 40mm deep wheelset, the 30mm outside width of the Firecrest vs. the 32mm measurement of the ENVE 3.4 front wheel might explain the speed difference I felt in its ability to hold speed.

But at its price and used primarily for gravel and alpine climbing, the Zipp Firecrest 303 disc wheelset is a great option for those riding purposes and a good value. And, for what that’s worth, I’m somewhat partial to the new logo too.

You can order it through these links to recommended stores Competitive Cyclist, BTD (BikeTiresDirect), Merlin, and Sigma Sports.

ENVE SES 2.3 – A PURE CLIMBER

The ENVE SES 2.3 is the epitome of a pure climbing wheelset. If I were writing a story about the ten best road climbs in the world for some glossy magazine, I’d ask the publisher to feature a photo of a cyclist on a bike with ENVE SES 2.3 wheels to give my article the utmost authenticity.

Many of us enthusiasts put our game faces on when it’s time to head up a 7% or steeper pitch, be it on a mountain road or a segment of a rolling course. We’ll shift down into an easier gear, slow our cadence, and grind it out.

Going down is usually a well-earned thrill. But, depending on your confidence in your bike and handling skills, the excitement can be full of nervous or freeing energy.

The ENVE SES 2.3 makes me want to seek out a well-paved climb and revel in the descent. While not the wheelset I would choose for every day, flatter rides or those on rougher surfaces, if it’s a day with 1,000 feet or so of elevation every 10 miles, I want to roll on the 2.3s.

Fellow-tester and P/1/2 road and crit racer Miles reported that the ENVE SES 2.3 “flew uphill.” Nate, a hill climb event podium regular, noted how well the wheelset transferred his power and felt “very light” for climbing. As a true uphill grinder, these ENVEs help me remember, if not relive, my younger days when I could get uphill as fast as my riding buddies.

It’s one of the stiffest and lightest climbing wheelsets we’ve tested. That’s an unbeatable combination. But, as we’ve noticed in its deeper wheels like the SES 3.4 and SES 4.5, there’s something in the way ENVE designs or laces or tensions its wheels that give them a spring-like response that sets them apart when it’s go-time.

Nate enthused the ENVE 2.3 is very lively and responsive. Even in his stiff Specialized Venge bike, “the wheels accelerate fast and give back the power you put in. And the hub engages immediately and is also nice and quiet.”

Miles bragged that he was winning town line sprints against riders with deeper wheels. He also used the wheels’ superior responsiveness and acceleration in pacelines to maneuver away from trouble when riders in front of him quickly changed their line without maintaining their speed.

Miles and Nate quickly noted how confidently and predictably the ENVE SES 2.3 went downhill. Miles leaned into them without hesitation at high speeds on technical descents during one P/1/2 race. With zero need to micro-adjust for side-to-side motion, Nate was totally comfortable riding downhill at higher speeds.

While they may look slight, the ENVE SES 2.3 are stiff, responsive wheels.

I’ll admit to being a bit more cautious than my better bike-handling fellow testers when cornering at downhill speeds on these ENVE wheels. While all of us rode the 2.3 with 28mm Schwalbe Pro One TLE tires, and I also tested them with the same size Continental Grand Prix 5000 S TR, I didn’t feel as confident leaning into turns as I do on climbing wheels that have a 25mm internal and 30mm external rim width compared to the 2.3’s 21.1 mm internal, 25.7mm external measured dimensions.

Call me spoiled or a wimp, but I prefer wider rims for my tires.

Nate and I also experienced less compliance on rougher roads on the ENVE SES 2.3 than on other climbing wheels we’ve tested. We inflated the tires close to the pressure ENVE recommends for these wheels, the tire width, and our weight, pressures consistent with the SRAM tire pressure calculator and a good deal less than the Silca one.

Still, you can feel every imperfection on an asphalt road and get a harsh ride on older or naturally rough pavement like chip seal.

And, of course, with its 28.5mm deep front wheel and 32.6mm deep rear, these aren’t aero stars. You can certainly accelerate up to aero speeds quickly, but keeping it there is more work than we’ve experienced on most other climbing wheels.

That’s less important in a paceline where drafting plays a bigger part. But, as a wheelset that’s less aero and less comfortable than most, the ENVE SES 2.3 isn’t one we’d choose for its versatility to ride both on climbing days and for everyday training and racing on various terrain.

But, for the fast-riding road enthusiast and racer looking for a dedicated climbing wheelset, the ENVE SES 2.3 is off the front. With a retail price of US$2850, £3350, €4000, you can order it using these links to recommended stores Competitive Cyclist, BTD (BikeTiresDirect), Merlin, Sigma Sports, and the ENVE online store.

BONTRAGER AEOLUS RSL 37 DISC – LIGHT AND NIMBLE CLIMBER

The Bontrager Aeolus RSL 37 disc wheelset is a lot of fun to ride. Scooting around with it on my bike brings me back to how I remember riding as a kid. You go left, right, up, down, and straight ahead without much thought. You go where you want without holding back.

These wheels are very light and yet stiff enough without being overly so. That combination made me feel agile and free while riding the RSL 37 in almost every situation. I climbed my most challenging steep, long “hill repeats” with comparative ease and did a few 50-mile, rolling rides on days after my hardest interval training of the week and felt totally relaxed and unfatigued during and at the end of those rides.

I’ll admit, I felt like something was out of whack when I rode the RSL the first time. It was early spring with plenty of crosswinds, and I was coming off too many stay-at-home-mandated Zwift rides. Early-season legs, wind in my face or from the side, and bib tights can make me feel a bit slow.

With the Bontrager RSL 37 disc, I cut through all of that. I immediately felt light, almost too light, and worried I’d get pushed around in the winds. Didn’t happen. The freehub engaged on command, and the wheels accelerated as quickly as I wanted and far faster than expected to the point where I had to shift down the cassette sooner than I normally do to keep up my speed.

At 37mm, the RSL rims are deeper than climbing wheels have traditionally been but about the same as the benchmark for that category set by the ENVE SES 3.4 (38mm front, 42mm rear) a few years ago. They’re nearly as deep as where carbon all-rounders have historically started (40mm) but no longer where they currently range (45-50mm).

For me, the Bontrager Aeolus RSL 37 disc is a pure climbing wheelset. It climbs and descends as well as any I’ve reviewed from any brand except for nearly 2x the price of the Zipp 353 NSW. Bontrager must also think so as they retired the 28mm deep Aeolus XXX 2 disc wheelset in its lineup for the RSL 37.

At the same time, Bontrager replaced 47mm deep all-around Aeolus XXX 4 with a slightly deeper (and wider and lighter) RSL 51. Makes sense, as I found the RSL 37 doesn’t sustain your momentum, as I’ve experienced with a deeper and slightly wider 45mm-50mm all-around wheelset.

The tires I rode these wheels with – 25C Bontrager R3 Hard-Case Lite, Continental Grand Prix 5000 tube-type tires, and the tubeless Continental Grand Prix 5000 TL tubeless – measured within a half mm of the RSL’s 27.5mm outside width.

As far as wheelset weight goes, I normally don’t make much mention of it because most of us can’t tell the difference between wheels weighing within 100-150 grams of each other that are typical of what you find from wheels in the same category. But since I’m reviewing a climbing wheelset and there may be a few of you weight weenies reading along, and principally because Bontrager gives you a few options that make a difference, I’ll go through it here.

If you want to use tube-type tires on these hooked rims, Bontrager provides you with a cloth-like rim strap along with the wheels that you can easily install by stretching it over the rim wall and snapping it into the rim bed. Per my scale, these weigh 22 grams per wheel.

The cloth strips won’t hold the air or sealant if you prefer tubeless tires. Instead, Bontrager also ships you plastic rim strip inserts to go into the rim bed. Those need some experience to install without cracking or breaking or getting them just enough off-center to mess up the bead lock alignment. They also add 62 grams to each rim, an unwarranted penalty if you care about climbing wheel weight.

The best solution is good old rim tape. One wrap or two. I tried both, and each sealed up successfully. The tape weighs 5-10 grams per wheel, depending on the kind you use and the number of wraps.

Bontrager has recently introduced some branded rim tape, and I prefer it to ENVE and Stan’s tape that I have historically used. You can order it here. Get the tape that measures the same as the internal width of the rims. In this case, that’s 21mm. I’m not sure if they will include the tape in the box with the wheelsets in the future.

No matter how you set it up, this wheelset will be light. I set them up initially for tubed-tire riding with the cloth-like rim straps (1376g) and later pulled them out and taped the rims (1352g, not including the valves) and mounted tubeless tires. With the 62g per wheel tubeless inserts, they’d weigh in around 1450 grams.

At 1352g for tubed or tubeless tires, it’s an easy choice.

Enough about climbing weight already! Going downhill and cornering at speed on the RSL 37 is a confident blast. And you don’t have to worry about crosswinds riding exposed roads. Simple. Fun and done.

As to comfort, these Bontragers aren’t any more or less so than most set up with tubes and the added pressure they require, even with the RSL’s 21mm inside width. As with any other wheelset this wide, you could safely lower your 25C tire pressure 5psi below the suggested level, use tubeless tires and drop it 10psi or mount up 28C tires. Wider tires would add a good deal more weight and further diminish your aero performance when riding above 18-20mph/29-32kph.

These wheels get an attractive glossy finish with black stealth logos. Also contributing to a skinny look and the low weight are the new DT Swiss 240 EXP hubs used on this wheelset. They roll a bit smoother than the last generation DT 240s, but their freehubs are a bit louder even after I regreased them. They’re not nearly as loud as Chris King, Industry Nine, or other hubs seeking attention, and DT Swiss hubs with a very similar design to the EXP have historically required next to no maintenance.

All in all, the Bontrager RSL 37 does a joyful job of its main purpose in life – climbing – and is a wheelset you can feel quite spry riding any day on rolling routes. Priced at $2700/£2100/€2650, you can order them direct from Bontrager.

ENVE SES 3.4 – PERFORMANCE IN THE FRAME OF THE RIDER

After an initial scan of fellow tester Nate’s and my evaluation notes for the ENVE SES 3.4 wheelset, previously known as the SES 3.4 AR Disc but otherwise essentially unchanged, I couldn’t help but draw a parallel to the saying about how beauty is subjective, being in the eye of the beholder and all that.

Even though we’re both “road cycling enthusiasts,” he and I are very different riders. He’s among the fastest non-pro roadies, best climbers, most practical gearheads, and highly analytical people I know.

Me? Not so much. Average speed (18-20mph) and climbing ability. Home wrenching skills, etc., Very enthusiastic, though!

It’s actually kind of surprising when our evaluations reach similar conclusions about the performance characteristics of the gear we independently test. I always welcome his take and those of my fellow testers because they add breadth and depth to my own. Together, I hope we cover the range of vantage points and rider profiles of those who read our reviews.

When it came to the ENVE 3.4 wheelset, Nate didn’t care much for it. I liked most of what it had to offer.

Looking closer at our evaluations of this ENVE wheelset, it became clear to me that what set us apart was probably more about our different bike frames and riding profiles than our mental frames or subjective views of what makes for wheelset performance “beauty.”

I point this out rather than try to write some compromise of a review as these distinctions may also apply to what you would experience riding this wheelset.

The 3.4 doesn’t fit neatly into a single wheelset category. At about 40mm (39.5mm front, 43.5mm rear with my calipers), it’s close but not as deep as most all-around road disc wheels that go 45-50mm both front and back these days.

While light (1432 grams with ENVE alloy hubs on my scale), the 3.4 is not a dedicated climbing wheelset either. ENVE makes the SES 2.3 for those looking for a dedicated climbing wheelset to do road races in the mountains. The SES 2.3 is a far narrower and shallower wheelset that weighs 200g less.

What separates the SES 3.4 is its 25mm internal (25.0 measured) and 32mm external rim widths (actually 32.1 front and 32.5 rear). That, along with the similarly wide, deeper ENVE SES 4.5 (reviewed here), makes it wider than most road wheelsets made these days that measure 19-21mm internal and 27-29mm external.

It is also as wide and often wider than most modern “gravel” wheels that range from 21mm to 25mm internal width.

So is it an all-around, climbing, and gravel wheelset triple-threat that’s great on all roads, as suggested by its original AR name? Or, is it the wheelset equivalent of a Swiss Army Knife, one that gets high marks for its versatility but doesn’t perform as well as those dedicated to either the all-around, climbing or gravel mission?

Whether on paved or gravel roads, Nate and I agree that the 3.4 is a laterally stiff wheelset. Yet this strength didn’t benefit Nate’s already stiff Specialized Venge aero frame. In my Parlee Altum, as quick and light as a road racing frame with the comfort and geometry of an endurance one, I enjoyed how the added stiffness of these wheels helped me accelerate uphill and start above-threshold intervals (or sprints for all you racers).

Mounted on my Giant Revolt Advanced carbon gravel frame, the SES 3.4’s stiffness was further apparent in the bike’s improved responsiveness compared to how it feels with most of the gravel alloy and carbon wheelsets I’ve tested.

Vertical or radial stiffness, better known as compliance or comfort, was a joy for me and a disappointment for Nate. With the latest model Schwalbe Pro One TLE 28mm tires on the 3.4’s 25C (or 25mm internal width) rims, you’d think they’d soak up every imperfection on our New England paved roads.

Tire pressure is key to optimizing wheelset comfort on any set of rims. It’s hard for some to wrap their heads (and pumps) around how low you should inflate a wheelset as wide as the 3.4. I pumped it to the 48psi ENVE’s tire chart recommends for my combination of body weight (145lbs/66kg), Schwalbe’s inflated tire width (29.0mm @60psi), and the 3.4’s 25mm internal width.

Yes, 48 psi. That’s not a misprint.

Nate, with his racer’s mindset, went about 8psi higher than his recommended level. (Details withheld to maintain the friendship.)

While the wheels soaked up large bumps and small potholes better than most, they were also notably more comfortable for me on paved roads than narrower wheels also run tubeless. For Nate, they were less comfortable than 19C and 21C carbon road disc wheelsets even though the 3.4s were inflated at least 10psi less than the level he pumps those to, also with tubeless tires.

Dirt and gravel road comfort are principally due to tire and inflation choices. So while I found them very comfortable at 30 psi on the trail, I can’t attribute it directly to the wheels.

The 3.4’s relative width and ability to absorb the bumps certainly created greater handling confidence that felt warranted cornering at speed on unevenly paved roads and when changing lines, with the right tires mounted, on gravel ones.

While even 21C road disc wheels are at their aerodynamic best on 25C tires, the ENVE SES 3.4 and 4.5 wheelsets are one of few truly designed (rather than marketed) for 28C tires. With the Schwalbe Pro One TLE pair inflated at 60psi (my measurement benchmark for 25C road wheelsets), the tires measured 29.0mm wide, making the rim width far wider than the actual tire width to minimize aero drag.

Note that the new Schwalbe Pro One TLE measures a size down from the prior generation (i.e., current generation 28Cs measure what last generation 25Cs did) and are as much as 1.0 to 1.5mm narrower than many older model 28C tires I’ve measured from other brands. So depending on the tires you use, you may find them measuring very near the width of the rim though not likely beyond the 3.4’s 32mm external rim width.

Either way, make sure you have about 38-40mm of room between your fork and chainstays for the 32mm wide rims and a 3-4mm buffer on either side of them for lateral deflection when cornering.

Also, be sure to use tires that are compatible with the hookless rim design that these wheels use (see list here). More tires are compatible now than when the also hookless, original 4.5 AR was introduced, and I believe most will before long as more road disc wheels go the hookless route.

All of that said, the 3.4 didn’t maintain momentum or otherwise feel particularly “aero” compared to better 50mm deep all-arounders and certainly not on par with still deeper aero wheelsets. On the plus side, it did feel a bit more sustained going forward than other wheelsets in the 35-40mm range. Also, the weeks of 10-20mph crosswinds we experienced during our spring testing rides didn’t affect this wheelset one bit.

The hubs ran smoothly with an average freewheeling sound from the ENVE alloy hubs that use Mavic Instant Drive 360 ratchet internals.

Aerodynamics also plays a role in climbing, once considered only a battle of grams. For Nate, a very accomplished climber using a very aero frame, he felt no difference on steep, 2-4 minute climbs between the light ENVE disc wheelset and his roughly 25mm deeper, 200g heavier Roval CLX 64 aero wheels. On punchy climbs less than 30 seconds long, the aero wheels seemed quicker for him, perhaps due to the aero benefit he carried into those climbs.

As an average climber who goes uphill far slower than Nate, I had the sensation of ascending freely on the 3.4 wheels, limited only by my strength and fitness. From experience, I know that most 1600+ gram aero wheels hold me back, their weight perhaps overwhelming any potential aero benefit.

Going downhill, the width of the SES 3.4 rim and tire combination made for a worry-free joy ride, the kind you feel on a rollercoaster knowing (or at least believing) the cart you are in is securely riding on rails.

Climbing dirt and gravel where speeds are far less than on paved roads, the 3.4 wheelset’s combination of lightweight and stiffness provided the feeling of turbo-boost responsiveness.

Clearly, the ENVE 3.4 disc is a very versatile wheelset. If you ride both paved and gravel surfaces and do a lot of climbing, this one wheelset which lists for $2850, £3300, €4000, can serve you well and save you from buying one for paved and another for dirt and gravel roads.

But, if you spend most of your time riding on paved roads and at aero speeds and your mental and, perhaps, physical frames are more biased to aero performance than climbing, the SES 4.5 would be a better choice.

You can get the 3.4 at the best prices from stores I recommend for their low price and high customer satisfaction ratings by clicking these links directly to this wheelset’s page at Competitive Cyclist, BTD (BikeTiresDirect), Merlin, Sigma Sports, and directly from ENVE.

BONTRAGER AEOLUS RSL 37 V – BONTRAGER’S ANSWER TO THE ENVE SES 3.4

While not the first, the Bontrager Aeolus RSL 37V is one of the best wheelsets for both paved and unpaved or “all-road” cycling.

With the breakout growth of gravel cycling and the renewed interest in cyclocross riding brought on by some of road racing’s top names, having a top-performing wheelset that excels in both those disciplines and also serves as a paved road climbing wheelset is an attractive do-it-all option.

It’s also far less expensive to have one top-performing carbon wheelset with a quiver of 28mm, 33mm, and 40mm or wider tires than a quiver of tires and wheelsets for that range of riding.

While ENVE may have set the standard in the all-road wheelset category, many leading wheelset brands are now trying to raise it with their own 23-25mm internal width, 30-40mm deep, 1400 or so gram wheelsets.

What sets the Bontrager Aeolus RSL 37V wheelset apart from the others in this field we’ve tested? My fellow tester Miles and I rode these wheels over three seasons (road, gravel, and cyclocross) and compared them to the ENVE 3.4 and more value-priced wheels to figure it out.

The differences are subtle but important, especially if you prefer the performance characteristics that the Aeolus RSL 37V successfully delivers.

As laterally stiff as any of the all-road or gravel wheelsets we’ve tested, the Aeolus RSL 37V’s stiffness feels more balanced than most. While it lacks the initial snap you get from the lay-up or bracing angles or whatever secret sauce is used in a wheelset like the ENVE 3.4, these Bontragers provide the consistent strength we can always count on, no matter the surface.

The Aeolus RSL 37V’s stiffness gave us precise handling and go-for-it confidence riding switchbacks down an alpine road, railing a turn on gravel, or accelerating out of corners to overtake a fellow cross-rider.

Even when Miles rode them in cyclocross races with 33mm tires inflated to 18 psi front and 20 psi rear, he was quick to point out the wheels never felt squirrely underfoot, always tracked extremely well, and yielded no give during crucial sprints.

The Aeolus RSL 37V’s robust lateral stiffness is joined by better vertical compliance than most, a combination you rarely find in a wheelset. Over the course of a 75-mile gravel ride or a day of climbing 10,000 feet in the mountains, both of which I did on these wheels, I was thanking them for helping to reduce the pain of those efforts.

The DT Swiss 240 EXP hubs used on these and other Bontrager, Roval, FFWD, and DT Swiss wheelsets have come in for criticism due to the noisier freewheeling than the previous model and cases of premature wear of the ratchet drive rings in the first runs of product that led to some hubs not engaging.

While DT appears to have rectified the wear and engagement problem – we didn’t experience it on this or any wheelset using the EXP hubs we’ve tested – the DT 240 EXP hubs are clearly louder than their whisper-quiet predecessors.

However, I don’t find them overly loud or annoying on the road in the way some freehubs on value-carbon wheelsets (including Bontrager’s own Pro 3V) can be or even as loud as those from the likes of Chris King or Industry Nine that riders prefer for their rich acoustics and pretty colors. To my ears, the low-frequency DT 240 EXP freehub noise gets washed out by the sound of small knob tires on dirt and gravel and doesn’t stand out against traffic noise on the road.

Sonic preferences aside, I find this hubset used in the Aeolus RSL 37V wheels to be a relative strength. They ride very smoothly and engage easily without the clunk I get when re-engaging some freehubs like the ID360 mechanism used in the ENVE 3.4 alloy hub. True, the points of engagement are similar and, at 10 degrees, more than I’d like to see on dedicated gravel or cyclocross wheelsets and more typical of a road wheelset. But I experienced an enhanced ride feel with the DT 240 EXP hubs on these wheels compared to those used on others in this category.

This all makes the Bontrager Aeolus RSL 37V a refined wheelset with strong, precise, comfortable, and smooth-rolling paved and unpaved roads.

I’d recommend no narrower than a 28mm tire width on a paved road. At my weight of roughly 150 lbs/68kg, I rode 28mm tubeless tires between 50 and 55psi and 38-40mm wide tubeless gravel tires at around 30psi. Unlike the ENVE and Zipp wheels, these Bontrager wheels are hooked so you can ride them with tubed clincher tires if you prefer.

The Aeolus RSL 37V wheels weighed 1421 grams with rim tape and tubeless valves. The rims measured 25.2 mm inside width, 31.5mm outside width, and 37.1mm deep. In addition to the DT 240 EXP hubs, each wheel uses 24 DT Aerolite spokes bladed, straight-pull spokes.

You can order them online from Bontrager for US$2700, £2100, €2650.

FULCRUM SPEED 25 – ROAD CLIMBER AND ALL-AROUNDER

The Fulcrum Speed 25 wheelset can serve two purposes for the road cycling enthusiast. It’s light and stiff enough to climb mountain roads, and its low-profile rims make it a suitable all-arounder for those riding in windy areas.

A smooth-rolling hubset, dead-quiet freehub, and ample compliance make the miles I’ve spent on the Fulcrum Speed 25 a real pleasure. My rides on this wheelset are more like low-stress outings than test rides.

High-intensity interval training, or HIIT workouts, seem less intense and less of a workout on this Fulcrum wheelset.  It makes climbing steep mountain roads less about the effort I’m putting into climbing and more about the experience I’m getting on the mountain.

It’s almost as if the Fulcrum Speed 25 is the wheelset equivalent of “comfort food” for climbing and rolling around on my bike on any terrain.

The Fulcrum Speed 25 labeling is modest, consistent with its smooth ride

Yet despite all of the pleasure I get riding the Fulcrum Speed 25 and my evaluation that it performs on par with the average of the climbing wheelsets we’ve tested, it doesn’t stand out for any one or combination of attributes beyond its smooth rolling and riding comfort.

It’s not as stiff as the stiffest climbers or as responsive as the most nimble ones. While this wheelset is certainly light at 1299 grams with a Shimano HG 11-speed hub on my scale, there are lighter and heavier ones in this climbing wheels category. And though my experience is admittedly more anecdotal than scientific, the Fulcrum Speed 25 has never been the fastest wheelset I’ve ridden up long, steep climbs in head-to-head comparisons against other climbing wheels.

Going downhill on the Fulcrum Speed 25 is a blast. With 28mm tires on its 21mm internal width rims, the cornering is confident, the ride comfortable, and the speed is as fast as you want to make it.

Yet at nearly 27mm deep, I’ll guess (since I can’t test) that you can’t go as fast as some of the others in this category that are 10-15mm deeper. On the flats, I don’t feel any aid from this wheelset in maintaining my speed above 20mph/32kph the way all-around wheels with a 45mm or deeper set of rims can provide.

Like all the wheelsets I’ve tested in the climbing category, including the deeper ones, this Fulcrum wheelset isn’t bothered by side winds, either on the flats or in the mountains. On the windiest days, I feel the high cross winds pushing my torso, but not this wheelset.

For some cycling enthusiasts, a light wheelset that climbs well, is unaffected by crosswinds, and is a real joy to ride on any paved road terrain is more important than having the fastest performer. If that speaks to you, this wheelset is worth considering.

With a retail price of US$2600, £2000, €2250 but available for less from some stores, you can order the Fulcrum Speed 25 wheelset at Bike24 and from a Fulcrum dealer.

BUT WHAT ABOUT…

Reviews of wheelsets only from Zipp, ENVE, Bontrager, and Fulcrum? I can imagine what you’re thinking.

Please don’t. I would love to share reviews with you of climbing wheelsets from Roval, DT Swiss, Shimano, Campagnolo, and a couple of others.

Model changes, supply chain issues, or limited US distribution have made getting some of the latest models from these companies quite difficult. I’ll hopefully be able to test a few of these in the coming year when they are more available.

* * * * *

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Thanks, and enjoy your rides safely! Cheers, Steve