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When to use those deep section rims(3 posts)

When to use those deep section rimstandem
Jul 29, 2003 11:08 AM
I noticed a lot of racers are using deep section (Zipp 404 type) rims lately, even in the Tour. I was wondering why all the racers weren't using them. It seemed like 1/2 the field had them on. I can understand them in the flat stages for their aero benefit but some still used them in the mountain stages. What is the criteria the determines when to use them or to stay with the old box rim wheels. I remember Phil questioning Jan's choice of them in one of the mountain stages. I see our local guys using them more in Crits as well.
The carbon rims are a special case.jw25
Jul 31, 2003 10:38 AM
With carbon, and using tubulars, you can build wheels that are as light as an Open Pro clinher setup, but have the aerodynamics of the deep rim as well.
For racing in a pack, I'd go light first, as the air is already churned by everyone around you, and the draft removes most of the reason for aerodynamic components, too.
If you're planning a long breakaway, though, slap the deeps on, as aero beats weight on pretty much any grade save HC. And again, with the carbon rims, the weight gain is minimal. Alloy rims, on the other hand, get pretty porky the deeper they go. Even there, though, the weight plays less of a role than the aerodynamics. In fact, once the wheel is up to speed, the weight nearly drops out of the equation.
I can kind of attest to this - Doing the same ride, alone, with 2 wheelsets. 1st is my light set, American Classic ultralite hubs laced to CXP-33's with 14/17's and alloys. Claimed weight 1535 grams all told. Average speed just under 20 mph.
2nd wheelset is some 1996 Mavic Cosmic Pros, rebuilt with 14/15 spokes by me, claimed weight 2100 grams per Starbike. Average speed 21.4 mph. The route is a big loop, mostly flat, no real climbing, and 53 miles around, so hopefully wind effects are minimized. Like I said, it's not hard data, but still applies.
I think a lot of the criteria the pros apply is financial - carbon rims are pricey, and you'll see the top riders using them, while the domestiques get the standard build.
As light as an open pro clincher setup?No_sprint
Aug 4, 2003 8:59 AM
What are you talking about? My carbon 38mm wheels are 1100 grams. I don't know that I've seen an open pro setup under 1700 grams. My carbon tubies (the set) with cassette and tire are more than 1 pound lighter than Bontrager Race X-Lites with stuff.