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Mavic Cosmic Carbone aero improvement method?

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Mavic Cosmic Carbone aero improvement method?

Old 08-05-11, 04:42 AM
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CdCf
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Mavic Cosmic Carbone aero improvement method?

I don't own any Cosmic Carbones yet, but I plan to buy a set later this year or early next.

Last week, I took a closer look at them in a local bike shop, and I noticed that the spoke holes in the rims are positively huge. Knowing that a large part of the "aeroness" of a wheel lies in how smoothly air flows in the rotational direction along the rim, this seems like a strange oversight on Mavic's part.

But then, if these holes were to be covered up, then that should have the potential of significantly reducing the aero drag of these already quite aero wheels. Some clear packing tape should do the job nicely.

Has anyone here attempted this? Is this nuts?
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Old 08-05-11, 06:48 AM
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It sounds like a lot of work for an almost unmeasurable benefit but, if you are going to do it, why not use clear or black silicone seal to smoothly fair in the holes. Done carefully it would be a lot neater than tape.
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Old 08-05-11, 07:50 AM
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Thinking that the Mavic Cosmic Carbone is not the wheelset you want, if you are going to mod a wheelset as soon as you buy it, you will probably void warranty, and the time you take to do the mod would have better been spent finding a wheel set with out the non isssue your trying to fix.
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Old 08-05-11, 09:45 AM
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1. There is no other wheel, at least not remotely within the same price range (there is a Zipp model, at more than twice the cost), that has the same set of specifications, i.e. aluminium braking surface, deep rims and clincher.

2. Not that I care the slightest about warranty, but placing a few strips of adhesive tape over a few holes won't affect warranty. Not in civilized parts of the world, at least (I'm suprised to see you're in the UK, jimc, as such a comment would be more expected from someone in the far more litigious US).

3. The time it would take to cover the holes up is probably on the order of half an hour or less. If that saves even as little as 1 W at TT speeds (I have reasons to believe that the effect would be greater than that), then that's far more than a half-hour interval session would give in terms of improvement.
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Old 08-05-11, 11:33 AM
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Originally Posted by CdCf View Post
1. There is no other wheel, at least not remotely within the same price range (there is a Zipp model, at more than twice the cost), that has the same set of specifications, i.e. aluminium braking surface, deep rims and clincher.
Shimano Dura-Ace C50 qualifies per your specs. No?

I have a set that I like very much.
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Old 08-05-11, 02:13 PM
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Hahaha......careful, those holes may well cause negative drag!
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Old 08-05-11, 02:25 PM
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Originally Posted by CdCf View Post
1. There is no other wheel, at least not remotely within the same price range (there is a Zipp model, at more than twice the cost), that has the same set of specifications, i.e. aluminium braking surface, deep rims and clincher.

2. Not that I care the slightest about warranty, but placing a few strips of adhesive tape over a few holes won't affect warranty. Not in civilized parts of the world, at least (I'm suprised to see you're in the UK, jimc, as such a comment would be more expected from someone in the far more litigious US).

3. The time it would take to cover the holes up is probably on the order of half an hour or less. If that saves even as little as 1 W at TT speeds (I have reasons to believe that the effect would be greater than that), then that's far more than a half-hour interval session would give in terms of improvement.
Soul CA 5.0, Hed Jet 6, SRAM S60, Shimano 7900 C50 CL, FP60's,
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Old 08-06-11, 12:17 PM
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Originally Posted by ********** View Post
Soul CA 5.0, Hed Jet 6, SRAM S60, Shimano 7900 C50 CL, FP60's,
Hadn't even heard of four of those! The SRAMs seem to be available over here at about the same price as the Mavics. Even the deeper-rimmed S80, which I think I'd prefer.

Thanks!
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Old 08-06-11, 01:32 PM
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It may be a non-issue for you, but an 80-90mm front rim can be an exciting thing on a windy day (and not in a good way) much more so than a 50-60. Also, since several tests have shown that internal vs external spoke nipples make little difference, I wouldn't be surprised if this doesn't matter either. If you really want to play with that, you might start with wax or something. That's what they did at Hed for the original H3deep wheels. Also, silicone between your tire and brake track will probably make more of a difference, but would make tire changes a real pain.
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Old 08-06-11, 02:46 PM
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Well, if it's an exceptionally windy day, I could just swap out the front wheel for my 7850-C24. My intent is to use them on a TT/tri bike that I'm going to buy for next year.
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Old 08-06-11, 03:22 PM
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Originally Posted by CdCf View Post
My intent is to use them on a TT/tri bike that I'm going to buy for next year.
I've been hoping that was your intent. My Carbones hang on the wall of my garage because they're not much good for anything but flat time trials and triathlons. The aluminum rimmed clinchers are too heavy for road racing or crits.
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Old 08-06-11, 05:51 PM
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Originally Posted by BikeWise1 View Post
Hahaha......careful, those holes may well cause negative drag!
Might not be so far-fetched. Think dimples on a golf ball. But if I were spending that much on a wheelset, I wouldn't want to have to do anything like that even if it were guaranteed to help. If the holes bother you, get something else.

FWIW, I love my Cosmic Carbone SLRs. I don't think they're that heavy at all given what they do - really nice aero w/ a good AL brake track. But then again, I'm 200 lbs and not anywhere near a weight weenie.
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