Rear/Front Rim profile and tire selection

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Zoro
Posts: 349
Joined: Wed Oct 30, 2013 12:52 am

by Zoro

This may be a 2-3 post thread, but you never know. Really two topics. I'd like some opinions. This is for racing tubulars, light rider, but I would think the principles apply to clinchers and normal wheels.

Rim profile:
It is quite popular for wheel sets to come with a deeper section rear wheel than front.
Why?
As the front is the leading edge wouldn't you want as deep as you can handle? As the rear gets a whole bunch of wind churn, why bother with the extra weight?

Larger profile tires on the rear.
I read folks that mix a say 23mm and 25mm like to put the larger profile on the rear. This assumes for discussion the 25mm carries lower pressure.
I (in the distant past) always did the opposite. I thought the lower profile higher pressure rear transmitted the energy better and the softer front made handling and hands better.

by Weenie


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WMW
in the industry
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Joined: Sun Jul 29, 2012 2:59 pm
Location: Ruidoso, NM

by WMW

A deeper rim is usually stiffer and stronger and heavier... which is good for a rear because the rear wheel carries more weight and all the torque, and has challenging dish. Deep rims are more effected by crosswinds which can be problematic on the front but not rear.

The bigger tire goes on the back because there is more weight there and aero matters less. All else being equal a larger tire has lower Crr.

But if you are a real weightweenie, you run light shallow rims and tires front and rear...
formerly rruff...

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