Zipp 303 Firecrest Carbon Clinchers

 

My history with Zipp products goes back 14 years. In that time I’ve ridden wheelsets that scared me, cranks I thought should have been more popular than the Beatles and bars that changed my expectations for all carbon handlebars. The overriding impression I’ve had is that of a company less satisfied with its own products than intimidated by the competition.

Were I to personify Zipp’s professional ambitions, I’d say they are a lot like Eddy Merckx was in 1972, which is to say, after picking up victory after victory as if he was strolling through the Europe’s most decadent buffet with a trash can-lid-sized plate, he went on to trounce the hour record. In talking with Zipp engineers, I’ve been struck by how they really don’t seem to give a damn what anyone else is doing. They seem to begin each day with a question—how do we improve our products? And to give full credit where due, when someone else does a nice piece of work, they are happy to hand out the compliments. It’s a classy touch.

Now, you can’t begin each day with a blank drawing board; a new wheel can take a year to develop. And yet, despite their ambitions, it’s not like Zipp hasn’t had the odd black eye, such as the wheel failures the Garmin-Chipotle team suffered at Paris-Roubaix in 2008. Thought to be former winner Magnus Backstedt’s last shot at a big performance, he broke both wheels on the cobbles and ended his day in the team car. But compare that with Tom Boonen’s performance at this year’s Hell of the North, where the Belgian regained his old form and rode away from the decimated field and crossed the line on a set of Zipp Firecrest 303s.

The 303 is Zipp’s third set of wheels to use its revolutionary Firecrest shape, coming on the heels of the 404s and 808s. And while the unusual shape was roundly mocked by some of their competitors, a quick check of HED and Enve web sites shows wheels with rims with a highly rounded spoke bed, not unlike the Firecrest shape.

CFD visualization of air passing over a wheel; image courtesy Zipp

For those of you who haven’t been following these developments—and admittedly the nerd factor goes critical almost instantly—here’s a little primer: Wind, as you know, is the single biggest factor in determining how fast you ride a bicycle. And crosswinds affect both speed and confidence; if you’re getting buffeted by a crosswind, you’ll tend to back off and focus on holding your line. Naturally, deep-section rims are more prone to steering input by the wind. Even though the wind will push on the whole of the wheel, a wheel’s design will determine just how much force the wind can exert on it. This is expressed as an imaginary spot called the wheel’s center of pressure. A traditional box rim with 28 spokes has a center of pressure that is a bit forward of the bike’s steering axis. As you increase rim depth (think typical deep-V carbon wheels) that center of pressure gets moved farther from the steering axis, giving the wind more leverage on that wheel, increasing its ability to push you around like a mop.

Deep-V rims were design with the idea that the rim was the trailing edge behind the tire. Firecrest treats the spoke bed as a second leading edge, if you consider the portion of wheel behind the steering axis. In rounding the rim profile at the spoke bed, Zipp ended up with a significantly more aerodynamic rim. It also resulted in a rather unexpected effect—it shifted the center of pressure behind the dropout to an area very near the steering axis.

I should mention here that center of pressure isn’t a single static location, which is why I used the term “area” rather than “point.” It, like center of gravity, moves around, but instead of body position determining it, center of pressure depends on yaw angle—where the wind is coming from.

Okay, so having said all that, what it boils down to is this: Crosswinds have very little effect on the 303 wheelset. Further, when the wind hits a front 303 the effect is to steer you ever so slightly back into the wind, but practically speaking my experience is that it simply cancels out the force of the crosswind against your body and the bike.

So how much faster is Firecrest? Zipp says 8 percent faster than their previous design; that number isn’t hugely encouraging given that wheels are only about 10 to 15 percent of the overall drag of a bicycle. At best, you’re going to realize a slightly more than 1 percent gain in speed. But the gain isn’t so modest as that. Because Firecrest is that much more stable than a traditional deep-section wheel, you can ride with greater confidence and if there is a wind, you needn’t back off your effort to concentrate on controlling the bike.

Image courtesy Zipp

Firecrest has realized yet another benefit. The wide rim—Firecrest is 25.1mm wide at the top of the brake track and 27.5mm wide at the bottom of the brake track—increases rim strength, and while that’s cool and everything, as you well know, that also gives the tire a wider footprint for better traction in corners.

I’ve ridden a lot of carbon clinchers. Some I liked, some I detested (but that’s for another post). The 303s strike an unusual balance. They are unquestionably aerodynamic. While I haven’t taken these to the wind tunnel, what I can tell you is that at crunch time on fast group rides, the 303s have aided my efforts. I notice a little something extra when accelerating or when putting my nose in the wind. The set weighs in at 1478g (676g for the front and 802 for the rear) which isn’t super light, but when combined with their aerodynamic advantage they are my favorite wheel for big jumps. And on longer climbs, when I will tend to slow down if there’s any sort of uptick in grade, a lighter set of wheels like this make it noticeably easier to get back up to my previous speed.

Unfortunately, there’s a dark side to this aerodynamic beauty. If you’re riding a Specialized Tarmac SL4 or Venge, you shouldn’t plan to mount these wheels on it. There’s very little clearance between the inside of the chainstays and the maximum width of the rim. That hasn’t stopped some riders I know from trying it anyway and claiming it isn’t a problem, but still. That whole voided-warranty thing can be a bitch.

I’ve done most of my miles on these wheels on a Super Record-equipped bike. Prior to switching them to that bike I’ll say that I had the impression that they were unusually stiff wheels, laterally. For reasons I can’t explain, the rear derailleur will rub spokes on every wheel I’ve tried when I put the chain in the big cog and stand up. I was surprised to hear the derailleur ting on the spokes of the rear 303. So it may be laterally stiffer than some, but it’s not stiffer than everything.

So that’s lateral stiffness. Vertical stiffness is another story. At 110 psi—the pressure I run most tires on most wheels—the combination of the 303s with Zipp’s Tangente clinchers is the most comfortable wheel/tire combination I’ve ridden. The difference isn’t huge; it’s not like running 80 psi with tubeless, but it’s enough to take the sting out of the rear end of a Felt F1. I probably wouldn’t have been able to note the difference had I not been riding these and other wheels on such a stiff bike.

The one consistent issue I’ve had with Zipp wheels has been build quality. On more than one occasion I’ve ridden a stellar rim and great hub laced together with a marginal build (this isn’t an issue peculiar to Zipp, though). Loosening spokes has been a recurring theme. Or at least, it was. The 303s I’ve been riding—and I’ve got more than 800 miles on them—have yet to come out of true. It’s worth noting that due to their angled brake track, if a Zipp wheel isn’t perfectly true both horizontally and vertically there can be a pronounced effect on braking. A rider will experience a high or low spot as either more or less grab at the brakes. It’s not a dynamite experience, but one I’m pleased to say didn’t take place with these wheels.

Another note on braking: Carbon clinchers and braking performance haven’t been good bedfellows. Some are as grabby as a drunk in a topless bar. Others have all the stopping power of an alcoholic at a frat party. The set of 303s I’ve been riding offer the absolute best braking I’ve experienced in carbon clinchers. Okay, so you’re wondering just what I mean by best; it’s a worthy question. What I mean is that the braking response is more similar to a set of aluminum clinchers than anything else I’ve ridden. I don’t want more stopping power, nor do I want less stopping power. I want to switch between wheels and notice only the change in sound, if even that.

And we’re not done on braking: I rode these wheels in Malibu, taking them down descents that some riders are now being advised to avoid. I’ve killed some carbon clinchers in Malibu, which is interesting given that I brake as little as survival instinct will permit. Braking is, after all, antithetical to fun. I don’t know a lot about the resins that Zipp uses, but I have at my disposal two details worth considering: 1) they have on staff an engineer with a Ph.D. in resin chemistry and 2) I am to understand that the resin used in the brake track cures at a temperature higher than any of their competitors; the brake track can handle temperatures north of 700 degrees, more than 350 degrees higher than the resins used by some of their competitors. I’ve yet to kill a Zipp wheel in Malibu; I know no one else who has done it. It’s an unusual record.

When last I dated I ran across any number of women who described themselves as “the whole package.” They were bright. Well-adjusted. Educated (graduate degree). Professional. In child-bearing years and willing. Not just healthy, but hot. They knew what they were and they weren’t going to date some guy writing a screenplay at Starbucks while on unemployment. These Zipps are kinda like that. Which is why they can ask $2700 for them.

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39 comments

  1. Matt

    Been on these wheels for 3,000 miles and 300,000 feet since April. Upgraded from sets of Ksyruims been riding past ten years. Similar to the review, no issues in the Malibu canyons, Santa Barbara, San Gabriel Mts, reliable and constant breaking, no different than breaking on my Al rims, no excessive heat. Routinely ride long dirt climbs/descents in east SD county beating the hell out of em on washboards, potholes, rocks in the shadows. Indestructible, confidence inspiring. Significant improvement in high speed cornering, notable increase in overall ride quality. Went with over 404′s for extra rear spokes, slightly wider tire profile, lower moment of inertia for long/steep climbs I enjoy. Durability key for me. Climb fine, that is to say, stiff when out of the saddle on lower cadence. Hold the line well in heavy cross-winds, not effortless, but manageable while keeping on the gear. They do give you that little extra in the group hammer fest, most noticeable on rollers/power sections. Expensive yes, but they have improved my cycling experience every time I throw a leg over.

  2. bryand

    I just broke a thousand miles on my new set this week, and I too really, really like them. In Vermont we have it all, hot 90+º afternoons, cool damp 50º mornings, terrible paved roads, great dirt roads, long steep climbs and technical descents. These wheels have been through it all and I have not had to true mine either. I would say that wet braking performance is certainly tolerable although I usually plan ahead in these situations… I did have to shave the brand new brake pads almost 1mm to get adequate clearance in my Red calipers. There is no brake shudder to be found but I do get a little howl from the rear rim despite playing with toe in. These really are great wheels and I’m glad to hear others think so too.

  3. MCH

    Off topic: bring back the Vuma Quad!

    OK, after the first paragraph, I couldn’t resist. On topic, the 303s could be the wheel to covert me to carbon. Zipp seems to bring another level of engineering to whatever they do.

  4. A Stray Velo

    I’ve ridden the new 3T Mercurio 60 wheels and they were also pretty damn good in crosswinds. Although I’m pretty sure they are not as wide as the Zipp’s they still rode great heading straight into a bad headwind. From what I remember they were more round at the spoke bed similar to the Zipp design. Bummer they were tubes, but they are cheaper…

    From what I hear the HED Jet series is just as nice as the Zipp’s but a little lighter on the wallet. I hope those weren’t on the “detested list.”

  5. Toddykins

    Given that ZIPP and HED shared joint patents on toroidal shapes, the jab at the latter seems unjustified. Both should be flattered that all the other wheel companies are copying the design now that the patents have expired.


    1. Author
      Padraig

      Toddykins: You’re clear that toroidal shapes are the generation prior to all the rounded spoke bed designs, i.e. pre-Firecrest, right? Zipp, Enve and HED have all moved away from toroidal. When Zipp introduced Firecrest, a few companies took digs at them for the “crazy” shape, HED included. This isn’t me playing favorites.

      Doctor Jim: I was reminded today when I went and did a bunch of climbing that I really prefer the 404 for flatter rides, though I love them on descents; they handle really well on technical descents. The 303s are just plain easier to accelerate on climbs where the pitch changes, so following a steep section, accelerating for a flatter section is noticeably easier with the 303s.

      So why don’t I run tubies? Here in SoCal flats are a pretty regular part of life. These wheels ride so well that the loss in serviceability (meaning how long it can take to change a flat) overwhelms the minor increase in ride quality and loss in weight. I might feel differently if I’m riding the wheels in Sonoma County, but for here, I want a clincher.

  6. Doctor Jim

    Padraig, I remember how well you liked the Firecrest 404′s. How do the 303′s compare? And why wouldn’t you go tubular and save 300 grams?

  7. Jeff

    I assume these would suit by Cervelo R5 quite well? Have been on Ksyrium SLs while training but thinking about buying a set of all-around usable carbon clinchers. Sounds like these fit the bill in your opinion?


    1. Author
      Padraig

      Jeff: Yes, the 303s are my favorite all-around wheels. But let me clarify and say that even though I get passed by caterpillars on climbs, I love riding in mountainous terrain. For flatter rides (anything with less than 2000 feet of climbing) I stick with 404s.

  8. Jonathan

    I’m going to have to pick up a pair of these today. I’m out in Malibu this week and managed to destroy a pair of Lightweights – which I used to think were bomb proof – descending Latigo Canyon yesterday.

    I imagine Latigo is one of those descents people are now being avised to avoid? If not, put it on the list!


    1. Author
      Padraig

      Jonathan: Sorry to hear about your experience. Latigo, while lengthy, isn’t by any means one of the most difficult or treacherous descents in the Santa Monicas. However, the frequency of the turns means that its possible to really heat up a pair of wheels. The good news is that I’ve yet to speak with anyone who has killed a set of Zipps on any of those descents. That doesn’t mean you can drag brakes the whole way down, but with good technique you can ride those roads repeatedly without problem.

  9. Jonathan

    Actually, it wasn’t a heat issue at all. I hit something (not sure exactly what; pothole? debris?) in the shadows around the 4.5 mile marker that blew out both tires. I was lucky to stay upright. I had ridden those wheels for over three years, occaisonally on some pretty crappy roads, and never put a scratch in them.

    The irony of the story is that I had just arrived in Malibu and was on my way to the bike shop on PCH in Zuma to pick up some CO2 cartridges (couldn’t take them on the plane with me), when I couldn’t resist taking a detour up Latigo. I was stuck with a double flat, no air, no cell service, the sun wa setting, so I had to make the judgement call to ride the whole way down on two flatted tubulars!

    Out of curiosity, which are some of the more treacherous descents?

    Thanks.


    1. Author
      Padraig

      Jonathan: All of the south- or west-facing descents (the ones that bring you back to the coast) have some treacherous moments except for Malibu Canyon (which is big rollers) and Encinal (which is really gentle). The most treacherous in my opinion are Las Flores, Tuna, Decker and Deer Creek, in roughly that order.

  10. Randy

    An FYI regarding tubular glue melting threshold and descending Tuna, since you’re on the topic of carbon wheels/durability/descending.

    I used to rail down Tuna on a regular basis until carbon brake track wear became an expensive issue(the last half-mile was a problem). During that time, at the bottom of the descent, I noticed that my tubular glue was often “glistening” between the base tape and the rim, and soft to the touch. According to Jobst Brandt, tubular glue will liquify at around 241ºF. I wanted to know how close I was to that point. I brought a small calibrated infrared thermometer with me and repeatedly measured the brake track temp immediately at the base of the descent. Regardless of ambient temp, it usually measured 181ºF +/- a few degrees. I presume that in interior temp would be relatively close to that. In six years of high-speed descending all of the descents mentioned I’ve never had the glue melt to the point where the tire slipped on the rim or worse, from the hottest Summer to coldest Winter days. I’m a 150 lb. rider and I try to use my brakes a little as possible while descending. I use Vittoria Corsa CX tubulars(21mm), Vittoria Mastik One Glue, and have ridden this set up on Zipp 303′s and Easton EC90′s.

    I hope this helps if anyone has been wondering about this stuff.

    Also, once I mount and align a tubular, I let all the air out and roll it on a 5/8″ dowel rod to push base tape firmly into the rim. This technique more firmly sets up the base tape/glue/rim adhesion than inflation pressure alone, and you will find that it reduces tire squirm. The upside is that your tubular/wheel will be more responsive in cornering and safer in regard a catastrophic blow-out and much less likely to “roll”. The downside is that when it comes time to remove the tubular it’s really stressful on your thumbs and requires a lot more time and patience.
    Remember that tubular glue is pressure-sensitive adhesive; keep your tubulars inflated to maintain the adhesion. Poorly maintained adhesion + bad bump in the road = rolled tubular. Pump them up every 4-5 days if you don’t ride them everyday.

  11. Darren

    I just bought a pair of FC 404′s and ride a 2010 Tarmac sl2. I notice that sometimes when I get up and sprint while riding and flex the bike there is some rubbing on the inside of the chainstay opposite the drive train. Have you heard of this issue? Is there anything I can do to limit this or even prevent this or protect my wheel/chainstay? Not to mention all that power I’m loosing when sprinting and getting that problem.

    Thanks in advance.


    1. Author
      Padraig

      Darren: The only warning I’m aware of from Specialized regards the 303s with the Tarmac SL4. I don’t know if they tried the Firecrest generation Zipps with their older frames. I don’t know of anything you can do to prevent the wheel from rubbing other than not using that wheel with that bike. Old school solutions like tying and soldering the spokes, or increasing spoke tension aren’t an option with those wheels.


    1. Author
      Padraig

      Davidski: I’m only aware of Boonen riding 303s with a Tarmac SL4 at Flanders. He rode a Roubaix at Roubaix and otherwise he told me he starts all races with a 404 front and 808 rear. As to why he might ride the 303s on a Tarmac, well he’s Tommeke and I don’t think he’ll have an issue with a warranty claim with either Specialized or Zipp.

  12. Darren

    @Davidski

    I believe that the Wheelset could work with some riders, esp much lighter ones, or riders with very strict form, but could wager a guess that they are rubbing on extreme efforts or climbs out of the saddle.

    Additionally, I believe the warranty is void on the 303 when used in the SL4

  13. Erik

    Padraig,

    Curious. Any idea of spacing/gaps/rubbing with C59 Italia? Ran 404FC on my M10s but have a C59 enroute and think the 303 is the way to go.

    (BTW) to all the Italians on board, forgive me, no I will not be using Boras, Fulcrums, FFWD, Miche, Lightweights or um…well you get the idea. It may be sacrilege but she’ getting ZIPP’s ;)


    1. Author
      Padraig

      Erik: Okay, now that I’ve stopped laughing in reference to your closing disclaimer (frickin’ hilarious), an answer: Sorry, but I’ve not heard any warnings regarding the 303s with any frame other than the S-Works Tarmac SL4. Talk to your shop and see if they’ll let you do an inspection on chainstay clearance before you commit; I’m assuming you’re purchasing all this stuff from the same retailer, which in this case could be really helpful for you.

  14. JuanJi

    Ok so here is the question…if you want have an sl4. Live in a windy city and want an all around clincher what would be your 1, 2, 3 option between:
    Eve 3.4
    Zip 202
    Zip 404


    1. Author
      Padraig

      JuanJi: In a windy place, at my size (160 lbs. give or take), I’d go with 202s or maybe a front 202 and rear 404. If you’re a big guy, someone everyone gets out of the way of, go 404s. And if you’re often confused with Spanish climbers, 202s all the way. The Enve 3.4s are a lot like a front 202 and rear 303, another fine option for you.

  15. Carlos

    Padraig, as someone who rides in the same places as you (though I live in NJ and ride here too) I am considering these wheels. Though I am fit, I am not spaghetti light. I weigh 175lbs and am considering 303 in the front and 404 in the back. Am I crazy? Isn’t Enve using this kind of set up? Anyway, hope to run into you one time in the Santa Monica mountains.


    1. Author
      Padraig

      Carlos: At 175 lbs. you’ll be fine on the 303s. What ENVE is doing is a bit like a front 202 and rear 303 or a front 404 and a rear not quite as deep as the 808. I think a pair of 303s is a pretty excellent way to go. And yes, hope to see you out there some time; that would be fun.

  16. Erik

    P~ First off, SUPER STOKED for you and the Family. Gripping mos. Brother, glad there is some wind beneath the wings again. Best wishes to you and the Clan.

    Anywho. So 3 weeks into the New Colnago and I ultimately dressed up the C59 Italia with 404FC and they were terrific BUT… I have really been spending more and more time in the hills (somewhat unintentional) but the low windy approaches into SMM’s have been agonizing on the 404′s as well as the descents being down right DEATH DEFYING. I am like the squirrelly freak-show in 1st wheel that leaves everyone behind me clinging to their brakes. And last week down in Orange County did some pace lines in the wind with the same results so you now what…404′s ARE ON EBAY!! I am going to the 303′s – they’ll be here next week. END OF STORY.

    Carlos, I am fit as well but also not a featherweight and I gotta tell ya, the heat dissipation standards offered by ZIPPy are just SO far ahead of anyone else right now that it’s a no brainer. I am no Physicist (I do periodically play one on closed circuit home television) but the facts as best I can read and research (hours and hours) into everything from Lightweights to Bora to Enve to Miche and on and on…NOT ONE of these other brands even attempts to claim they have the same level of heat dissipation standards which Zipps have. For me that was the Clincher (hee-hee). Anywho, lets be real, all these brands are rad, it simply comes down to what rocks your Jam!! Would love to ride…we can spend all day climbing and then accuse the other of being more fit when we start sucking wind!! Hit me anytime. keihoop@gmail

  17. Stephane Leduc

    Hi Padraig,

    Really nice post.

    I’m currently ridding Mavic Ksyrium ES which I found to be really stiff on the rear end while I’m getting older. They are one of the best wheelset I ever rode but I’m looking into something more confortable, with more flex.

    I’m thinking about upgrading to a set of 404 or 303 but still in the process of getting some knowledge about which one to choose. While reading many reviews, it’s been said that the 404 firecrest wheel is a very stiff wheel compared to older models, and compared to 303s.

    Since you’re riding on 404s, what is your input about the stiffness of the wheel, confortwise, and stiffness/flex comparison to 303s?

    I’m riding mostly flat areas (Montreal, Canada) and I’m 225 pounds. I don’t own many wheelset, it will be my everyday wheelset.


    1. Author
      Padraig

      Ryder: I’d contact Specialized on that. Because that frame is aluminum, there’s a chance that the chainstays aren’t as big and will offer more clearance. I bet your local dealer could get an answer on that pretty quickly.

  18. Erik

    Ryder, I have changed completely off ZIPP and onto ENVE Classic 45′s now. As well Im off the White and Black C59 and was privileged enough to grab one of the ARMY MATTE GREEN C59′s. If Padraig will allow it, it’s definitely picture worthy.

    Anywho, been on the ENVE Classic 45′s now for a few hundred good miles AND MOST RECENTLY DID A CENTURY on Black Friday IN ORANGE COUNTY, CA. – why the caps you ask? Because in Orange County on Black Friday it RAINED ALL DAY. The 100 miler was 7 hours of riding, 6.5 of which were in full blown rain.

    SO – that said, wanna know how ENVE’s stand up against others in general – happy to share my experience. But wanna know how they stand up in the RAIN – I can DEFINITELY tell ya that!!

    All said and done though I am really finding the ENVE’s and ZIPP’s to be neck in neck. Zipps are so damn great I cant say a bad thing about em. Of course there is minutiae I can break down; which hubs, why classic over ENVESys or 303 vs. 404 as all rounders etc etc. But truth told, I am lucky enough to ride with the guy who imports Legend Bikes to the US and he runs Miche everything, (sorry, Campy SR with Miche Calipers and wheels so not “everything”). Also, some friends of Padraig and I who run a LBS in Santa Monica build up some crazy exotics and run em all from Lightweight to ENVE and everything in between…so no arm chair analysis here, I am a data junky (not a weenie) just an analysis junkie and I’ve been with a broad swath of peeps riding a few marquee hoops lately and at these types of prices if you want some input, happy to provide. I certainly cant afford to buy multiples so I have to make my purchase count.

    Happy to chat on/off board pending P’s approval.

    Also, P – btw, Erik Jr. scheduled to enter the World on Dec18…wish me luck man!! My first. You think Colnago makes a size 1 Sloping C59…?

    All the best and Happy Holi-daze!!

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