These reviews of the Zipp 303 NSW and Bontrager Aeolus XXX 4 wheelsets first appeared alongside reviews of other all around rim brake wheelsets in my post The Best Carbon Road Bike Wheels.


Little more than a year after Zipp introduced its first line of NSW wheels, it came out with an updated line in 2018. The latest 303 NSW is wider (19C), lighter (1510g), and has an updated rim profile. Along with its NSW siblings, the new 303 is the first line of Zipp rim brake wheelsets that are tubeless.

The hubs and brake tracks that were new with the earlier NSW carry over as does its premium price.

I and my fellow testers rated these the Best Performer the last time we reviewed wheels in this category. I wondered if the changes made them any better.

Zipp 303 NSW carbon road bike wheelsIn a word, yes. They are more comfortable on long rides and mixed terrain than before. They accelerate and climb a tad better. They still have an uncanny way of seemingly ignoring the crosswinds. If you run them at lower pressure with tubeless tires, they seem to be even more surefooted than before. If you run them at higher pressures, they feel as responsive as a whip.

My fellow tester Nate, the all-business, often stoic Bullet Train and A group ride leader at my local bike club who also led his race team to another TTT victory and won his age group up the New England equivalent of the Mt. Ventoux climb this year called the 303 NSW “absolutely dreamy.”

Seems the ability to run this 303 NSW carbon clincher wheelset tubeless at <80 psi for Nate, who is all of about 155 lbs/70kg, created what he described as a super smooth ride with great stability and control, soaking up bumps and harsh road conditions.

I seldom hear Nate or the few other super talented and competitive riders I’ve met talk about comfort and stability. This wheelset brought our that reaction.

At the other end of the spectrum, I was surprised to hear my fellow tester Moose, who weighs about 200lbs/90kg (and thus the reason for his nickname), speak positively about the 303 NSW’s stiffness and responsiveness. Zipps characteristically aren’t as stiff as other wheelsets and under Moose’s frame, I thought they might be a tad soft.

Nope. He found them sturdy enough and really liked their responsiveness. Despite the range of alloy and carbon wheels that were shallower and deeper and the same depth as these we rode this summer, he kept coming back to the 303 NSW as the one he wanted to ride for this event or that long weekend away.

When I ride these wheels, I feel like the Wayne and Garth characters from the old Wayne’s World skits who repeated “We’re not worthy” when someone famous invited them to stick around.

Why? When I get the 303 NSWs up to speed, which doesn’t take long, they seem to hold my momentum without me having to work really hard to keep them there. When I go out on a windy day, my 150lb/68kg body can get pushed around but the NSWs seem to anchor me to my line. The wheels are snappy on legs that haven’t had much snap in them for more than a few years now. They also climb easily for me.

The braking on these wheels is probably their most debated characteristic. The performance isn’t debatable – they are as capable on dry roads as alloy wheels and nearly so on wet ones.

Instead, the noise that comes from these brakes creates the greatest divide in the evaluations I and my fellow testers have had and that some of you have shared in your comments in past reviews about other Zipp wheels that use the same brake track design.

While it’s not annoying like the shrieks you have likely heard from older carbon brake tracks and pads, some don’t like any noise while others think the Zipp brake sound is cool. Perhaps the best analog is the reaction people have to noise coming off of freehubs. Some like it while others want it quiet. Ironically, the hubs on the 303 NSWs freewheel without a whisper.

All in, the new 303 NSW is probably the most versatile and complete all-around set of carbon bike wheels a road cycling enthusiast will ever need. A racer might want more of this and not care about that from their wheels but for those of us who enjoy a wide range of riding from individual training to aggressive A and B group rides to long endurance rides to serious climbing to riding at high speeds and want one wheelset to help them deliver great performance and riding experiences from one wheelset, the Zipp 303 is hard to beat.

Am I worthy of this level of performance from a wheelset? Probably not but I’ll gladly take it. And, if I’m going to pay the market price of about $3200/£2600/€3000 from this one, I’ve earned that level of performance or at least bought it. If you want it for yourself, you can find it online at my top-rated stores Competitive CyclistMerlin, and others I recommend at Know’s Shop.

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There’s something about my long-ago memories of driving a Chevrolet Corvette and my recent experience riding the Bontrager Aeolus XXX 4 wheels that connects.

No, it isn’t the phallic imagery of a Corvette and the XXX label of the latest Aeolus, though perhaps you could make that connection. (Sorry that I just did.)

Rather, it’s the rush of rolling at speed they both provide. While a lot of cars and wheels roll fast, it’s what happens in the moment of speed that makes life behind the wheel and in the saddle exciting.

Hitting a turn at speed carries more unknows than rolling straight. The Corvette’s wide wheelbase, wide tires, and low chassis provided me the handling performance to confidently hit every turn faster than I’d ever done before.

Bontrager Aeolus XXX 4 carbon road bike wheelsSimilarly, the Bontrager Aeolus XXX 4 mounted with 25C tubeless tires stick it in the corners. Fellow tester Nate enthused they always seemed so much more planted and stable than any other carbon clincher wheelset he’d experienced, especially in turns with bumpy pavement.

I measured the internal rim width between the bead hooks at 21.1 mm on these and other Bontrager Aeolus XXX series wheels. That makes them the widest rim brake carbon bike wheels we’ve tested, notably wider than most which run 19 mm or 17 mm these days.

Their 27.5 mm external rim width across the brake tracks is nearly as wide as others like the Enve and Zipp in this category. The external rim width along with the mounted and inflated 25C tire width helps contribute the XXX 4’s aerodynamic performance while its wide internal rim dimension and the wheels’ stiffness lead to its great handling and comfort.

Many road disc wheelsets have been at 21 mm internal for a couple of years now and I can confirm riding them is a similar speed-liberating handling experience. The better support a wider rim provides to the sidewalls of the same 25C tire makes a real difference. It’s nice to see Bontrager bringing this to the rim brake world.

Moose took these wheels for a ride down the 8-mile, 8% average grade asphalt road at Whiteface Mountain, home of the Lake Placid Winter Olympics. Hitting speeds of 50 mph, he reported that the crosswinds made the riding the XXX 4s “a little sketchy” but not enough to back off his exhilarating speed.

I don’t know if that’s Moose’s daredevil approach to going downhill on bikes (and skis) that he prefers but I do know he arrived safely at the bottom and was so excited after the ride he sent me a half dozen texts about his descent.

While neither of us could find strong crosswinds, Nate and my experience in moderate ones on these wheels were fine. They did acknowledge the breeze but it didn’t affect our steering or cause us to do anything unnatural.

Unfortunately, you sometimes need to slow down. Fortunately, all three of us were impressed with the braking power and modulation of these wheels on dry roads; they are among the best here.

On wet roads, however, they are no better than earlier generation carbon clincher rim brakes. Like the Vette, leave these Bontragers in the garage when it’s wet outside.

The XXX 4s are “stiff enough” to climb and sprint but they are more above average in this all-around carbon clincher pack than clearly superior compared to others on this criterion. They are considerably heavier than the 1400 grams claimed by Bontrager – 1556 grams on my scale. This puts these XXX 4s are 50-100 grams heavier than most in this rim brake carbon road bike wheels category.

Why is there such a big weight difference? I measured them with the rim strips you need to ride them tubeless. Bontrager doesn’t include the strips in their claimed weight. It’s unusual to have rim strips weigh so much. Most rim tape adds 5-10 grams per wheel. These rim strips weigh about 65 grams per wheel.

I asked the Bontrager support line and a dealer whether I could run them with tape rather than the strips. Neither recommended it. The strips add the height and rim bed gutters you need to get your tubeless tires locked in.

If you want to ride them with a tube and clincher, they will be far lighter. But, to gain the versatility, comfort, and handling that we experienced, run them tubeless even though they will be slightly heavier.

The added weight makes for an average, more dampened acceleration than a lively, springier reaction when you want to accelerate. Their DT Swiss star ratchet hub internals provides quick engagement (and quiet freewheeling) but doesn’t improve the acceleration enough to make a difference.

If you’ve got the watts in your legs, you can probably get these wheels up to speed much in the way a Corvette corals the horses under its hood to get you from 0 to 60 mph faster than most.

It’s what the Corvette and Bontrager Aeolus XXX 4 do at speed, more than how fast they get you there, that separates them from the competition.

You can order these wheels online for $2400 by clicking through on this link to Trek.


So what separates the two Best Performers? The Bontrager XXX4 is the stiffer of the two. That stiffness shows up in more precise cornering and the feeling of more direct power transfer when climbing. The Zipp 303 NSW is a more responsive, more lively ride and feels like it is less work going uphill.

They are both comfortable but the Zipp holds the edge here and it shows up on long rides. Choosing to ride them tubeless, which makes both more comfortable, and where you set the inflation pressure will likely have as much or more effect on your comfort than choosing between the wheels.

The XXX 4 and 303 NSW brake extremely well on dry pavement though the XXX 4 does it quietly. Because the XXX 4 is stiffer, you can set up your brake pads closer to the rims and get better modulation in your braking. If you find yourself riding on wet roads often, the 303 NSW will give you notably better braking.

As a light B group rider, I loved both but preferred the livelier Zipp wheelset and it being totally unfazed by crosswinds. While I prefer a quiet freehub, I wasn’t bothered by the brake noise.

I’d have thought the slightly stiffer XXX 4 would win Moose over but he liked the responsiveness of the 303 NSW and the range of things it did so well.

Despite loving the comfort of the Zipp, Nate gave the nod to the XXX 4 for its better handling and brake modulation. He also felt the way it handled varying terrain would make it a great wheelset to use during cyclocross season.

Performance comparisons and preferences aside, the price of these two wheelsets differs by quite a bit. While neither of these wheelsets is a bargain, the Bontragers are about $800 less expensive. That’s an important consideration if you weigh the price of performance in your decision.

You can compare key performance and other criteria of these two wheelsets against other all arounders in my post The Best Carbon Road Bike Wheels.

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  • Great article as usual. I currently have a late-2018 set of Zipp 303 Firecrest (rim/clincher). I had to buy them because of the price I got from an LBS. Although I do find a bit of rear wheel flex (I can hear a little brake rub) when I’m climbing out of the saddle — I’m more of a Moose than a Nate — I don’t mind because everything else about the wheels has been stellar. That being said, would you feel that the NSW represents an advancement that might warrant a switch from the previous generation, especially for a current owner of current gen Firecrests? Also I’m assuming the disc brake version of the NSW behaves the same way as the rim, save for the better braking in all conditions? (Asking because I’ve been pondering building my first bike from the fame up, and well, based on a few of your previous articles — disc brakes are the way to go if considering a new bike)

    • Sal, tubeless, hub, rim width are the biggest differences and improvements in this second gen 303 NSW from the 2018 303 Firecrest which is essentially a first gen 303 NSW. If that doesn’t matter and given the price, I would stay with what you have.

      You can see my reviews of your 303 Firecrest and the disc brake version of the 303 NSW by using the search bar at the top of this (and every) page. Steve

  • Sorry – I am not an engineer nor a physicist but and sorry to be a party pooper but am surprised at your consistent useage of such unclear terms such as:

    “*more* confortable” (…so, how much more? 10% , 50%, 100% more…?).
    “A *tad* better” (umm, what’s a tad? 1%, 5%, or 9%)?
    “*seemingly* ignoring crosswinds”? (So do they or do they not ‘ignore’ crosswinds? …)

    Lol…One person’s tad or more or seemingly or seems is definitely not going to mean the same thing quantitavely, as anothers’.

    Perhaps that’s the whole point here for fellow cyclists … i.e Take this *review* blog *opinion* with a grain of salt and as fun, entertainment. However for objective comparaisons perhaps consult lab data (even they are sometimes skewewd) or Hambini’s carbon wheel lab tests for objective data.

    Thanks for the entrrtainmrnt nonetheless!

    “They are *more* comfortable on long rides and mixed terrain than before. They accelerate and climb a *tad* better. They still have an uncanny way of *seemingly*ignoring the crosswinds. If you run them at lower pressure with tubeless tires, they *seem* to be even more surefooted than before.”

    Fellow tester Nate enthused they always *seemed* so much more planted and stable…”

  • Steve: Thanks for your content and presentation. Top notch! I discovered you after my bike fitter told me my next logical step was a power meter and carbon wheels. I am test-riding Firecrest 303s and like them very much. I chose, however, to purchase the XXX 4 based on my positive experience with Trek, including their customer satisfaction commitment, but mostly due to your recommendation.

    I am in my 50’s, weigh 200 lbs, ride recreationally, put many laps on the race track in cars and motorcycles; I appreciate comfort, ride and handling, but mostly I just want to go fast.

  • Steve, I read several of your articles regarding the Zipp NSW 303 and the Enve SES 3.4, and I am stuck on which one to purchase. Both would be disc and I would run them tubeless. I live in N. Cal, so I do alot of climbing. On most of my 70 to 80 km rides, usually at least 3,000 feet, often a bit more. I have some cannondale OEM czero shallow wheels now, run 28 schwalbe pro one tubeless. The wheels are ok, but seem a bit soft and zero aero benefit. I am definitely looking for more aero, but do not want to go backwards in terms of climbing ability. So, which one would you suggest for both climbing, but also aero advantages.
    Lastly, I notice that Enve has 5 year warranty and Zipp a two year. Which is a significant difference, but I also noticed that Zipp appears to no longer offer the lifetime crash warranty. Enve does, and it says no matter how you screw up, you can buy a replacement wheelset at 50% of cost. Which is a darn good deal. Am I missing something, or are Zipp wheels only protected by just a two year warranty? Which would be a massive difference value wise between Zipp and Enve. Thanks for all your good work.

    • Andrew, in my Best Carbon Disc Wheelset post where you also just commented, you can see a write up of the two wheelsets you are asking about and a table that compares them on my key performance criteria. Some of your decision may come down to how much climbing you do (3K feet on a 70-80K ride wouldn’t suggest to me that you want a dedicated climbing wheelset unless the climbs are super steep, like 10% grade, and for a long time like at least a mile or two), how much you weigh (ENVEs are stiffer and I’d recommend them over Zipp if you weight >185lbs), how much weight you can trim from your body or bike to make your climbing more efficient (even 5 lbs will make a 10x difference over reducing wheelset weight 100g), how fast you ride (if your ride <18mph/29kph average, depth doesn't matter; you aren't going fast enough to get aero benefit, >20mph/32kph aero matters and deeper wheels are just one of the ways to improve your speed), tire width (you wouldn’t put a 28C Schwalbe Pro One or any 28C on any carbon disc wheelset except an ENVE AR as a tire wider than 95% the width diminishes the aero benefit of a deeper rim), tire selection (some have lower rolling resistance than others and this can improve your speed more so than tire width at sub aero speeeds), price (you can buy the ENVE for about $700 less with the right hub selection), warranty/crash protection as you mentioned, looks, brand association, and perhaps some other things I’m forgetting. Some/all of this goes into your buying decision.

      If you haven’t done so yet, you might want to look through my post on how to choose the best wheelset for you. I find many enthusiasts who are ready to move on from stock wheels can get very turned around by all the marketing and tech buzz and it can make for a tough upgrade decision. Once you define your goals, riding profile and budget, it makes it a little easier to choose. Steve

      Help me keep reviews and comments free of ads and bias by buying your gear through links on the site and at Know’s Shop. Thanks

      • Steve,
        Thanks for you quick reply. Yes, all the marketing and tech buzz really does leave one with a sort of deer-in-the-headlights feeling. For what it is worth, I weigh 175lbs, I realize I will be dropping down to 25c tires no matter what I pick, and since I do go fast >20 when I am not climbing, aero should help/be worthwhile.
        Actually, I had hoped you would find I was wrong about the warranty difference because I was leaning toward the Zipps. The length of a warranty reflects a manufacturers belief in their product and/or is baked into a premium price (put another way, the bean counters at corporate headquarters estimate the future claims rate on a product and try to ensure a fair profit margin based on original sales price in light of estimated future warranty costs.) However, Zipp now has a premium price without a premium warranty (in fact, it is now a very poor warranty), which means somewhere along the line Zipp probably had a high rate of warranty claims and decided to pull back on coverage because it was hurting the bottom line. At the other end of the scale is Industry Nine, which gives a full lifetime warranty for its i9 series carbon wheels. And as noted, Enve which has 5 years product warranty and lifetime crash protection.
        Which is all a way of saying, given the relative hair splitting relating to the performance of Enve/Zipp (both are obviously outstanding), the lack of Zipp’s belief in its product, and the potential negative impact on my pocket book, means I am much to my disappointment taking Zipp off of my very short list of choices. Thanks again.

        • Andrew, Yikes. You’re way over thinking this. Lifetime warranties and the like are more marketing. If the product sucks, yeah there will be a lot of returns but they will show up relatively soon, not in the out years. I’d expect the return rate past 2 years on what the warranty actually covers (workmanship and materials defects) are likely quite slim. There are certainly reasons to take Zipp off your list, price being the first one that would come to mind, but the length of their warranty is way down the list for me. Zipp (and ENVE and a few others and not i9) is one of the more innovative wheelmakers (and marketers) out there and that innovation produces some of the better performing wheels I’ve ridden. That’s what you are paying for. Steve

          • Probably, but like you I am a tech guy, but unlike you I am not in a position to test gear before I buy. So I read and read and read. Anyway, went with the Enve SES 3.4 disc. I live in the SF Bay Area and rides with protracted 10 to 15 degree climbs abound. I wanted to push the aero edge as far as I could without degrading my climbing from the low profile carbons I have now. For your records, the front wheel only(no tape or stem) 646 g, advertised as 645g. The rear wheel, 768g, advertised as 775g. Can hardly wait to put them on the road tomorrow. Your reviews regarding these wheels, and all your articles about choosing wheels generally have been invaluable to me. Best site on the web. Thank you.
            As for the warranty issue, I disagree that it should not play an important part in the decision. And I am surprised you think so given the attention you have paid to the cost, cost of ownership and warranties when reviewing wheels. It is all about value. And it is not just about the money. Fortunately, I can afford any wheel I want and if I break one and have to replace it on my own, it will tick me off, but will not affect my finances. However, I did not get to the point where I can say that, without always considering value when it comes to spending my hard earned dollars. That is where the warranty comes in.
            The really short version is that I have a background/expertise in consumer product purchases, and I know more than a bit about companies and the whys and wherefores regarding the decision making process that goes into establishing warranties. There is something called the “signal theory” which pertains to warranties. It has been studied and written about by countless eggheads and economists because of how it affects the marketplace. As the phrase suggests the warranty is meant by the company to be, and is usually received by the consumer, as a “signal” regarding the quality of the product. Some of this may just be common sense, but a lot goes into a company’s process regarding establishing the terms of a warranty.
            Which brings me to high end carbon wheels and my comments above. Zipp made an affirmative decision to reduce its warranty to just two-years. It has nothing zero in terms of crash protection. Bontrager, which you review above, has 2 years, plus lifetime crash protection which provides for a reduce replacment cost. Enve, 5 years, plus lifetime crash protection. Reynolds, flat out lifetime warranty. Stans (FYI–love the Valor Pros on my gravel bike), 5 years plus lifetime crash. And the list could just go on. All of those makers have top-end rims over $2k, and some approaching $3k, depending on the build. Same as Zipp (Firecrest vs. NSW), yet Zipps stands out as the only one that walks away after just two years. Why?
            Your observation about time-to-failure may be accurate, but your conclusion is 180 degrees out. If you are correct about the two-year failure time, then Zipp should ad a few more years because it would basically cost them nothing after two years. Right? It would be great consumer good will and advertising— and a signal that they believe in their product. But that is not what has happend. So my best guesstimate is that either Zipp has been getting killed money wise on its older, but better warranties (it is always about the $$), or they are just riding the wave of their well earned laurels by saving a ton of money on warranty claims with a thin warranty, while charging a premium price; thereby increasing the bottom line (its always about the $$). Maybe someone at corporate HQ concluded that Zipps are so popular, that they can get away with both a high price and a low warranty. For now that is. Good for them.
            The problem is that there is not anything to suggest that Zipp makes rims of a massively higher quality than the other top makers. In fact, the signal is just the opposite. Either those manufacturers make rims of a quality worthy of lifetime warranty, or they are soon out of business when the claims start coming in for failed wheels. That is their signal. Zipp, not so much.
            In the end for me, given the narrow performance difference, I just do not see any reason whatsoever to pay 2-3k for a Zipp wheel given their signal, when I can pay the same and receive lifetime protection.
            If I find the time, I will make up a chart ala the ones you have done regarding wheel reviews, but with just a whole bunch of manufacturers warranty terms. It would be interesting to see how that factors in to others purchasing high-end carbon wheels.
            Thanks again for your help, and cheers.

        • Andrew, you make some good points. An alternative but opposite viewpoint is that longer warranty periods can be used a marketing tool for inferior products as well. Not saying ENVEs are inferior, but the marketing technique of the lifetime warranty worked on you.

  • Hi Steve et al, Would the Roval CLX 50 rims fit on my 2017-18 Cervelo S3 (chainstay cleareance etc). Cervelo say there should be 4mm clearance but then state a maximum chainstay tyre/rim width of 30mm which is confusing. If not are there any other good similar wheel options for the Cervelo.
    Many thanks.

    • John, You typically want 4-5mm of clearance on either side to allow for lateral deflection. Measure the minimum chainstay (and fork) width and work back from there. For example, if it’s 40mm min, you can put a rim/tire that has a 30-32mm max width. Steve

      • Steve: After riding a loaner set of 303 Firecrests, I decided carbon wheels were worth the investment. I bought the XXX 4 based on your review and am thrilled with the purchase. I find the Bontragers to be more stable, especially through the corners, brake better and sound better everywhere. Most obvious is my ability to carry momentum up short hills and carry speed with confidence. Thanks for the assist!

  • Andrew…Kudos on the timing of your opinion/comments…. looks like Enve just announced expansion of their warrantee to “Lifetime Incident Protection”.

    • DaveMac. Thanks. I was back on ITK looking at shoe reviews and went back to this string, saw your comment and then checked on ENVE site. The new warranty is a game changer. ENVE goes so far as to actually say that even if you run the bike mounted on the roof of your car into the garage and destroy the wheels, they pay 100% to replace, for life. That is actually as powerful endorsement of a product as I have ever seen. As for my new 3.4 SES Discs. Two rides last weekend, one with 3,500 in just 9 miles. Wheels absolutely perfect for climbing, and then fast on the flats. Mounted with Vittoria 25c Corsa Speed tubeless. Plumped up to about 26.5mm wide, at 85 psi front, 90 rear. Been a diehard Schwalbe ProOne guy for a few years now, but while I remembered everything else to build up my new wheels, forgot to order tires. The Vittorias were all I could get on short notice. Nice ride. We will see how long they last.

      • Andrew: Do let us know how long they last. Have the same wheels and have been wanting to put the new Corsa speed tubeless tires on them when battling the mountains but their reputation of being very delicate has held me back.

        • Sure thing. If you a looking for wheels that really purely go up really well, but are willing to give up the benefits of aero on the flats and the descent (which is what the 3.4s give you), then look at something like Stans Grail CB7 Pros. The rims weigh 300g each, which is about 100g per rim less than 3.4, or even the 2.2s. Now you have to be a light weight rider, probably sub-160, to not over-flex them, and the specs say tubeless tires can go a max of I think 85 psi, but with the mass of rotational weight on the edge of the rim that much less, you will be able to tell the difference. I have some now discontinued Stans Valor Pros- 650b wheels with 300g rims that I use on my gravel bike, and those things just jump when I push them up a hill, and I am running big old Schwalbe G-One 40mm tires.
          Regardless of what wheels you chose for climbing, you have to decided if you want to totally sell out a get maximum climbers and say to heck with the rest. Sort of like what the real aero guys do when they get there 7.8s. One trick ponies but boy are they good at that trick.

        • Brian. As promised, here is my report on the Vittoria Speed Tubeless tires. I will start at the end. After about eight rides, I took them off and literally threw them away. But realizing your results and riding conditions my vary, I will share my overall experience with the Vs, beginning to end.

          Installing them tubeless on my 3.4s was ok. I have done alot of tubeless setups over the last five years. The tires easily slipped onto the rims. In fact, so easy that it did give me pause to think how stretchy and thin the sidewalls were. Setting them up tubeless was a bit harder than other tires. If SchwalbeProOnes are 10 of 10 on the easy scale, then these were a 7. Even though I could get them to “pop” on with my little portable air compressor, even with the sealant in, they would at first not hold air very well. Overnight, from 90psi to 30. After thoroughly spinning the wheels on my truing stand and a few rides to make the sealant dispurse, they did however start holding air, and dropped just a couple psi overnight. However, the fact that these tires did require so much sealant just to hold air is probably a result of the aformentioned sidewalls being relatively soft/not stiff so that they did not sit as firmly, as say the SPOs, in the rim hook. By comparison, the replacment SPOs I installed two nights ago are holding air without ANY sealant being added.

          Anyway, got them on, put 85 psi front and 95psi rear and went riding. About that—First, with tubeless I prefer less air. 75/85 psi is standard, unless I am going on a fast and smooth ride. Then 80/90 to 90/100 is ok. Unfortunately, at 85/95 the ride is noticeably harsh on those roads where I would normally go with lower pressure. However, the problem with the Vs is that the minimum specified pressure is 87psi. So while 85 works, I would never go below that just because V thinks that would be a problem holding the tire to the wheel—tubeless or not. I guess I could have read the package and seen this before I purchased the tires, but it is worth noting that if you want all of the benefit of tubeless in the form of lower pressure for some rides, the V Speeds will not work.

          The ride was otherwise good. The traction at speed and in corners was great (until it wasn’t–see below), and the tires felt fast, but not noticeably faster than SPOs or Cont.5000TLs I have ridden. The problem was durability and handling.

          Durability. I only road on paved roads, and only roads I have ridden countless other times. I ended up with two large gashes, enough so that the sealant sprayed out all over my lower leg. Now in fairness the sealant did its job, so all I had to do was pull over, let the hole seal, and pump up the tire with my mini-pump and be on my way. The problem was that when I inspected the tires after my last ride,I could see they were already being goughed and trashed. I could even see where the sealant had “plugged” one of the holes. It worked, but looked like it would eventually wear out and leak. In all my years with the SPOs I had a total of one flat on these same roads, and that is when I carelessly clipped the edge of a pothole and tore out the sidewall. Otherwise on these same roads, no problems.

          And then there was the treadline. There is a notable “curb” or drop off where the tread ends and the sidewall starts. I have never seen anything like it, and there is certainly nothing like it on SPOs, Contis, or even VittoriaCorsaRace, all of which I have ridden. The result is that if you lean over far enough and come to the edge, you “fall off” the tread and the traction gets sketchy. I had a heart-stopping high speed two wheel drift that I swear was the result of me rolling off the edge of the tread. The problem, besides the “curb”, is also that the portion of the tire which has the tread is about 25% narrower than the SPO by comparison. It seems the Vs are so concerned with lightweight they shaved every bit off the top and sidewalls, hence the curb. Which is ok if you are mainly straight line on smooth roads, but……

          So…. I concluded that repeatedly having to rely on the sealant, was not something I could live with because it appeared by the existing wear/damage rate that sooner rather than later the sealant would not be enough, and I would be stuffing a tube in the wheel. And even if I could live with that, with all the high-speed mountainous descents I ride, the aforementioned tread issues were just not worth the worry.

          Anyway, I went back to my trusted SPOs. I thought about the Conti5000TL, but after going to so much effort to keep the edge of the rotational weight down with my Enve 3.4s I did not want to give a bunch back with Contis excellent, but heavy tires. Cheers.

          • Thanks a lot for taking the time to write this Andrew. I figured the tires were delicate but wow(!) – I’ll take a hard pass on the Corsa Speed!

  • Steve: any recommendations for a pure climbing wheel (rim and disc both)? I have the Enve 3.4 and love them [as my all-around wheelset for a mountainous area] but what set would you choose when for those days when going up mountains that are ~8%-10% for miles on end with several 15%-18% sections?

      • Thanks Steve. So I guess my question is, at what point would you consider something like the Lightweight Meilenstein wheels or similarly lightweight wheels (and perhaps even tubular versions of that type of wheels)?

        • Brian, Not sure what level rider you are or what your training is all about but at the price of Lightweights and even the ENVEs for that matter, I’d make sure you could benefit from the difference, assuming you can afford it. I put gear 7th on my list of How To Ride Faster on Your Bike. Dropping 3 or 4 pounds, doing hill-specific training, getting the right bike fit and drivetrain set up, getting enough sleep and recovery, eating better, etc. are just some of the things you can do that will have a much bigger benefit than going up from 3.4s to Meilensteins. If you’ve got all of that and other things on my list already dialed in as far as it can go, better gear will take you incrementally further but at a higher price. Steve

  • I thought the Zipp 303 NSW and Firecrest had the same “Showstopper” brake track, but here you have the NSW braking with + and the Firecrest with 0, why is that?

    • David, Good catch. I’ll fix it. Thanks. I was probably thinking back to the earlier Firecrests which didn’t have it. Steve

  • Dear Steve
    I’m glad you saw the article you wrote.
    Let me change the wheel set
    My current wheel set is Giant SLR0 AERO 55mm (DT240)
    But I just want to change the front wheel to ZIPP 303 NSW(Cognition)
    How is your opinion?

    Thank you
    I am from Taiwan

    • Ben, If your objective is to reduce the effect of crosswind, you will get some benefit from the profile of the 303 NSW. It is excellent in crosswinds. I can’t think of any other benefit of changing just the front wheel. Steve

      • Dear Steve
        Thank you for your reply

        I want to ask you a question.
        If the front wheel is 303 NSW, the rear wheel is 404 NSW, before and after the mix
        Does the benefit of the rear wheel only affect the forward inertia, and has nothing to do with the crosswind?
        What are the special benefits of this?
        Because many of my partners are like this
        Usually riding a hilly or mountain road
        Please also help you reply
        Thank you,

        Best Regards

  • Dear Steve
    Thank you for your reply

    I want to ask you a question.
    If the front wheel is 303 NSW, the rear wheel is 404 NSW, before and after the mix
    Does the benefit of the rear wheel only affect the forward inertia, and has nothing to do with the crosswind?
    What are the special benefits of this?
    Because many of my partners are like this
    Usually riding a hilly or mountain road
    Please also help you reply
    Thank you,

    Best Regards

    • Ben, Triathlon and time trial riders often use a front wheel that is shallower than the back wheel. Typically it’s a 404/808 setup. In crosswinds, a front-wheel deeper than the 404 (60mm or so) can be hard to handle. I would guess your partners are doing this for similar reasons though it’s not something I think is optimum. You certainly can use 404s on hilly or mountain roads but it is really better for flatter terrain at higher speeds. The 303 is a better choice for that situation. There may be some benefit but I don’t know what you would get from the 404 in the rear on that type of terrain. Talk to your friends and let me know why they do it so I can learn from their experience. Steve

  • Steve, wow – I am so happy I found your site! Thank you for putting so much time into these reviews. My situation is as follows: I am a 175 pound rider on a rim brake tarmac. Most of my rides are flat/rolling, have long straight always, have punchy steep hills (no more than a few minutes per hill) and have about 700-1000 feet of climbing per every ten miles.
    I generally avg 19-20mph solo and in the mid to high 20s in a group. I currently have the 2018 303 firecrest but want new wheels to a.) go tubeless, and b.) reduce rear wheel flex so I can bring my calipers much closer to my rear wheel. I can’t decide between the enve 5.6 with the latest alloy hub and the 303 NSW. Any thoughts? Thanks again!

    • J, You’re right at the weight and probably power where riders need to choose the trade-off between Zipp’s greater comfort and lesser stiffness. It’s similar to the tradeoffs between the two I’ve written about above. If you haven’t yet, take a look at my review of the 5.6 here to confirm my thought that, from what you describe, you’d probably be happier with the ENVE. Steve

      • Thanks, Steve! I was leaning that direction.

      • Since this site has been so helpful to me in my decision to purchase the 5.6 Rim Brakes, I figured I would share my perspective coming off of the 2018 Zipp 303 FC clincher (non-tubeless).

        First, Steve’s review was spot on. These wheels are very fast! I only have 200 miles on them, but I have found that once you get over ~21mph The wheels seem to “push” you forward. I don’t know how else to describe it because I have never experienced it before. I have multiple PRs on Strava with these wheels.

        The brake track (rim) is also the best I have ever experienced, and in my view, it is light years ahead of the Zipp “Showstopper.” My frame has direct mount brakes and the combination of the direct mount and the ENVE brake tracks make it feel like I have disc brakes. Seriously.

        As far as hubs go, I went with the Enve alloy hubs, and thus far, I really like them. I choose them after speaking with the folks at ENVE who guided me in that direction when i told them that I wanted minimal maintenance.
        The hubs have a slightly quieter yet deeper (“throatier” if you will) freewheel sound compared to the Zipps. The wheels don’t flex very much (see ya later brake rub!)

        Last but not least, ride feel. For context, I am coming from 17mm internal rim width, clincher, with 25m GP 5000s inflated to 90 PSI. These ride is a little firmer than I anticipated, however, GP 5000 TLs inflated to 80 PSI, are still MUCH more comfortable than my previous set up listed above.

        All in all, unless you ride in the mountains or ride gravel, I would say these could be the best wheels out there, especially for rim brake. The aero dynamics, brake track, hub choices, and ENVE warranty make these a no-brainer. And in-care you can’t tell, I am an ENVE fan-boy now. This quite possibly may be the only wheel company I purchase from in the future.

  • Hi Steve – thanks for the insightful review. I ride a 2011 Specialized SL3 expert carbon bike with rim brakes and stock Fulcrum 3 aluminum wheels. I do not qualify as a cycling enthusiast (not enough time for rides and I usually go only around 14-15mph) but when I go I really enjoy the rides. I’m 40 and weigh 170 pounds and I mostly ride on paved roads, some laps in parks and some hills here and there (no more than 12% grade).

    I am considering upgrading my bike’s wheel set to the 303 NSW’s clinchers. I would expect to ride these wheels for many years.

    With under 1000 miles per year (though would love to do more) and good care do you think these wheels would fall apart after say 5 years?

    Do you think I’m overshooting here getting such high end wheels for a medium range bike?

    Would it be silly to run these as tubular clinchers?

    Many thanks!

    • Eugene,
      – If you don’t ride them in the rain or on sandy/gritty conditions, they should last you that long
      – Yes, way overshooting
      – Yes, tubular is way too much hassle and not as good performers compared to tubeless these days.
      May I suggest you take a step back and read through this post about finding the right wheelset for your situation.

  • Steve – thanks for your response, very helpful and appreciated!

    I read the linked post and seeing these two reasons why the 303 NSW’s may not be the best choice for me now: I do not yet average 18mph nor do I have a high end bike where the cost of the NSW’s would be 30%-40% of my bike’s retail.

    While I feel that I will improve my rides’ average speed, certainly the cost of my
    bike will never change.

    Wondering if these indeed are the reasons you feel I’m overshooting with the 303 NSW’s or if I missed something from your answer?

    Thanks again.

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