I’ve recently received a set of 2007 Zipp 303’s (the dimpled 44mm deep rim) with the intention of making it the ultimate all around wheel for both my roadie and my tri bike. I intend to get a cover for the rear but it appears that the cover form CH aero weighs almost as much as the wheel (it will be trimmed fairly significantly due to the deeper section wheel but still). Is the cover form Wheelbuilder any lighter? Is anybody making a CF cover anymore (more about teh bling than anything else). Is the trimmed cover from wheelbuilder worth the extra coin?
I’ve recently received a set of 2007 Zipp 303’s (the dimpled 44mm deep rim) with the intention of making it the ultimate all around wheel for both my roadie and my tri bike. I intend to get a cover for the rear but it appears that the cover form CH aero weighs almost as much as the wheel (it will be trimmed fairly significantly due to the deeper section wheel but still). Is the cover form Wheelbuilder any lighter? Is anybody making a CF cover anymore (more about teh bling than anything else). Is the trimmed cover from wheelbuilder worth the extra coin?
The trimmed cover from wheelbuilder.com IS a CH Aero cover. It’s just custom trimmed to your particular rim size and the attachment holes are re-cut as well. The additional $25 charge over the cost of the CH cover is well worth it IMHO since trying to do it yourself can have less than “ideal” results.
Trimming off the outer edge of the cover will reduce the weight. However, look at the “all up” weight of your wheel plus the cover and it isn’t going to be much greater than a typical disc, if at all. My guess is that the trimmed cover will add ~300 gm to the wheel weight. Besides, the aero advantage gained by the cover will more than counteract ANY additional weight, especially on flat or rolling courses.
Edit: I just looked them up, and a 303 tubular rear wheel is 608g and a clincher is 844g. Add on 300g for the cover and you’re at 908g and 1144g respectively. Compare this to the Zipp tubular and clincher discs which are 950g and 1222g respectively. What weight disadvantage?? 
The weight is not a real big concern for the tri bike, I was jsut suprised at how heavy the cover was. I hate the thought of a 540g wheel cover on a 600g wheel 
If the cover gets down to 300g then I’m still riding on a semi-dimpled, tordial, lens shaped 900g disk for about $100 over what is spent on the wheel. I’d say that is pretty good return on investment.
i still hope to hear how a disk cover on an aero wheel compares to the new bulge disc?
hoping Zipp or somebody will post some real world or even guesstimate numbers?
The weight is not a real big concern for the tri bike, I was jsut suprised at how heavy the cover was. I hate the thought of a 540g wheel cover on a 600g wheel
If the cover gets down to 300g then I’m still riding on a semi-dimpled, tordial, lens shaped 900g disk for about $100 over what is spent on the wheel. I’d say that is pretty good return on investment.
I’m just guessing on the weight…obviously, the deeper the rim, the lighter the cover will be after trimming. Even if it ends up being the FULL 540g weight, on a “bang for the buck” basis, it’s still a HUGE bargain.
One way to save a bit of additional weight is to just use electrical tape around the edge of the cover on the deep rim section. Jens does this with his 808 wheel and forgoes using the little fasteners. He claims it’s a sound attachment technique. I don’t have the luxury of trying this since I’m using my cover on a PT/Open Pro wheel and there’s not much space between the edge of the cover and the brake track to put a strip of tape.
HA! You just beat me to it!
I don’t knwo if you will see any numbers from zipp that will say a $100 wheel cover wil rival the weight and aero of their ne $1200 super disk.
just a little something… why do you care about weight? do you think youw ill be faster on a 600g wheel compare to a 1200g wheel? well, you might save a few secondes(3-6 second over a ironman) but you will lose on aerodynamic…(5-10 minutes) Weight is not important at all unless you want to enter a bragging context with friends about how light your stuff his…
my 808 is about 850g +500g wheel cover= 1400g for the fastest possible disc… and i race ironman canada on it(people say it s a hilly course) and never feel a difference… and in the end, i did just fine with that wheel
the concept of weight is in your head… it will not affect your performance in a significative way to worrie about it…
All very true jonny. my tri bike is no prize winner on the weight podium, but I’m a bit of a weight weenie and the thought of doubling the weight of a wheel with a plasitc cover seems to scream “There is a Better Way!” If the trimmed weight of these covers is only about 300g than that it’s no big deal and will apease my inner weight weenie
i still hope to hear how a disk cover on an aero wheel compares to the new bulge disc?
hoping Zipp or somebody will post some real world or even guesstimate numbers?
The best you’ll get is what’s in this thread starting with Josh’s first post and going down:
http://forum.slowtwitch.com/...tive%20drag;#1460321
There’s a few “nuggets” in that thread Note that Jens found that his 808 tubular with a cover was faster than a Zipp clincher disc (with a 404 sized “bulge”).
well, in this case, i understand but as long as you know it s simply mental and as nothing to do with performance… it s all good.
i think what most people need to focus is the body weight… this is where the huge gain in performance can happen(on the bike and run)!!!
for the cover… i will say, you can use tape only to fix the cover to the rim… no need for the hardware… at least for mine…
of course then there’s always the question of how deep of rim is best with the disc cover?
I like the idea of a wheel cover on a deep wheel. I have a Stinger 90 rear wheel I was thinking about getting a cover for. In the end I haven’t been able to do it because I can’t convince myself that there would be really any gain in time saved over an IM. If someone has some numbers explaining the time savings between a good deep wheel (Zipp 808, Hed 90) and one with a cover I would really appreciate the insight. I just can’t believe it is more than a handful of seconds over a 40k. Even if it ends up being a couple of minutes over an IM it is still kind of hard to rationalize in my very small head. Any thoughts on this?
Hi All,
A better option would be to use the silicone caulk that they sell that is removable. It is sold at the big box stores (such as the evil empire of Home Depot), mainly for sealing around storm windows so that it can be removed in the spring. You just have to take your time, and you will come out with a nice job.
Stephen J
This is an interesting debate to which I can add no meaningful insight.
However, on the “rationalize” front, I offer that for those on the edge of qualifying, those seconds matter…For example, when I qualified, the difference between my qualifying slot and not going to Kona was under a minute…Was the disc worth it to me? Was peeing on myself for 10 hours worth it? Were those few extra workouts in the rain worth it? If I’d been 1 minute slower, I’d probably say no. However, when combined, it WAS worth it.
With that said, I’ll probably be riding 404s with a wheel cover next season (clincher) because it’s the option from which I’ll get the most utility over the course of a season (and I’m really tired of gluing tubulars after 23 years of bike racing).
Cheers,
Puskas
If that’s the silicone sealant that you use for fishtanks, it is an absolute bloody pain in the backside to get off a carbon wheel once it’s on
Xav
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if you end up having a very windy day like ironman canada, the difference between a disc cover on a 808 and a 808 alone is MINUTES over 40km…
on a course like hawaii with very hard cross wind… if a disk was legal, it would save 10-15 minutes over a 808 on a hard windy day…
if it s a calm day, the difference isnt big but if there is chance of strong wind and specificly cross wind… it would be RIDICOULOUS to not get a cover…mostly anybody can afford 65$ if they alredy have a 808 of hed 90…
Tom FYI the wheelcover for my 58mm 404 is already in the 400+g range so it will be close to 500g or more for the 44mm 303. not that it matters much…
Last year I rode a P3sl (650c) with a 404 front and Renn 575 rear (clinchers/EVO CX) in a half ironman relay and posted a time I never thought I’d ever be able to beat. I had an awesome ride … for me.
This year I was on a P3C (700c) and had an 808 rear with wheel cover. I had an 808 front, but forgot it at home and had to race on a Mavic Cosmic Carbone that was only in the car 'cuz I’d crashed it a few days before and it had a badly bent spoke and a nice hop in the rim. I straightened the spoke with a pair of pliers just before the race and rode with the hop in the rim. It was a very blustery day. I knocked over a minute off of the time of the previous year. Lots of variables, but I’m sold on that 808/wheel cover combo. Jens recommended it. He warned me it was heavy (it is) and promised me that wouldn’t matter (it didn’t). I loved the ride quality compared to a disk and the sound is really cool. It sounds like a turbocharger.
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Tom FYI the wheelcover for my 58mm 404 is already in the 400+g range so it will be close to 500g or more for the 44mm 303. not that it matters much…
Thanks…like I said, it was just a guess For some reason I had it stuck in my head that the covers were ~1lb = 454g instead of the 540g. I’m thinking the thing will be more like mid-to-high 400s when cut for a 303. I’ll bet if he emails or calls Rich at wheelbuilder.com he’d be able to tell him, if the OP’s really curious.
But, as you say…not that it matters much
I think it was 480g for the cover that I put on a 303 a couple of weeks ago if that helps a bit more
Xav
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