Benefits of deeper section rear wheel?

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neeb
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Joined: Tue Jan 27, 2009 8:19 pm

by neeb

Did anyone else notice that Nibali was mixing his wheels on his Milan San Remo winning bike? From the footage I've seen I think he had a Fulcrum Speed 55T (55mm) on the back and a 40T (40mm) on the front. Enve of course do their 3.4s, 4.5s, etc. But how much does this make sense? Aren't the vast majority of the aero benefits coming from the front wheel?

In Nibali's case I assume it was just to reduce any potential trouble from crosswinds, while maybe keeping the rear as stiff as possible for the Poggio.

Just wondering why, if it is a good combination, we don't see pros mixing their wheels more often.

Matt28NJ
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by Matt28NJ

It looks dope.

pdlpsher1
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by pdlpsher1

You are right about the front wheel makes the biggest difference. But an aero rear wheel still helps. That’s why you see disk rear wheels in time trials. The shallower front wheel is to enhance control in crosswinds. I have a pair of the Boras 50s and a pair of the Bora 35s. I get a lot of wind here and I’m going to try the 35/50 combo.


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Lelandjt
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by Lelandjt

Deeper is more aero and stiffer. If there were no cross winds you'd probably use that same deeper wheel up front too, but there are. I've been on 50/38mm for a couple years and love the combo for windy Maui. Front is light and unaffected by wind while being aero enough. Rear is light enough, stiff, aero, and doesn't seem too affected by crosswinds.

dastott
Posts: 80
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by dastott

I live on the coast and found 60mm front and rear combo quite stressful. Since putting a box section Mavic Exalith wheel on the front with latex tubes I have found it much easier. A nice combo, I lose in aero but gain in stability and rolling resistance.

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themidge
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by themidge

Chris Froome does it too (Shimano DA c35/24 + c50 I think), but IIRC only in the mountains, probably for all of the above reasons.
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KCookie
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by KCookie

I ride with a Gipfelsturm front and Obermayer rear, this really helps with the strong crosswinds around the Adelaide hills that I ride. The rear always seems well planted and haven't felt the need to swap that to the Gipfelsturm. Also can't be bothered to keep changing the rear wheel.

bm0p700f
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by bm0p700f

I have 50mm front and rear and I ride those in 20 mph winds with no bother apart from the wind being tiring. Even stronger winds are no bother over shallower wheels except for the wind of course.

The rim profile makes all the difference.

TobinHatesYou
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by TobinHatesYou

On days with >15mph winds in the mountains, I can feel the wind attempting to push out a 40mm rear in tighter cornering situations. It's pretty disconcerting and feels like the back is drifting slightly even though there's no appreciable loss in grip.

pdlpsher1
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by pdlpsher1

How much wind a ride can tolerate while on deep profile wheels depends hugely on the rider’s weight. The very light riders are much more sensitive to side wind forces. Once I was on 50mm rims and a strong side gust picked up my front wheel and dropped it a foot away. Miraculously I didn’t crash.


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bm0p700f
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by bm0p700f

Rim profile has more of an effect than rider weight. I have 38mm deep rims that are more effected by wind than my 50's.

The wheel you had that hot picked up was it a v section narrower rim by any chance.

I gave a set of 88mm deep v section rims in winds they are a handful.

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