# Different rim depths on front and rear tires...?



## Cni2i (Jun 28, 2010)

Hi everyone. Not sure if there are really any "true" benefits of doing so, but I've seen cyclist put smaller rim depth wheels on the front and deeper rim depth wheels on the rear. For example, a Zipp 303 or 404 on the rear and a Zipp 202 or 101 on the front. Are these cyclists trying to maximize weight/aero advantages? I have a set of DA c24s on one bike and a set of DA c35s on another. Was considering putting the c24 on the front and the c35on the rear. Any performance benefit (even if minimal) to having this staggered setup? Thanks.


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## walamt (Jun 7, 2011)

Performance or aero effect is small for aero rims in general, the reason they are using shallower rims for the front is to counter the wind deflection from cross winds so people are having a bet each way, ie, trying to get some aero benefits without too much cross wind annoyance. Lots of pro teams are using this setup now. The extreme example of this is the Time Trial events where they will use and 80mm rim on the front with a full disc rear.

A 24/35 combo, I wouldn't worry about it, your going to gain nothing out of it. I'm going to get a new set of wheels and tossed up between 50/50 or 38/50, I decided on 38/50 as a compromise for cross winds. Out on a ride today even my 25mm rims with blade spokes , the wind was deflecting my front wheel.


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## kbwh (May 28, 2010)

A deeper rear rim also compensates for the narrow flange spacing necessary on the rear hub. The rear wheel takes more stress than the front, so a taller/heavier rim with more spokes makes perfect sense. 

As for crosswind behaviour, it seems to me that rim cross section is more important than rim height.


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## Cni2i (Jun 28, 2010)

walamt said:


> Performance or aero effect is small for aero rims in general, the reason they are using shallower rims for the front is to counter the wind deflection from cross winds so people are having a bet each way, ie, trying to get some aero benefits without too much cross wind annoyance. Lots of pro teams are using this setup now. The extreme example of this is the Time Trial events where they will use and 80mm rim on the front with a full disc rear.
> 
> *A 24/35 combo, I wouldn't worry about it, your going to gain nothing out of it.* I'm going to get a new set of wheels and tossed up between 50/50 or 38/50, I decided on 38/50 as a compromise for cross winds. Out on a ride today even my 25mm rims with blade spokes , the wind was deflecting my front wheel.


In terms of performance, you're probably right.


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## Cni2i (Jun 28, 2010)

kbwh said:


> A deeper rear rim also compensates for the narrow flange spacing necessary on the rear hub. *The rear wheel takes more stress than the front, so a taller/heavier rim with more spokes makes perfect sense.
> *
> As for crosswind behaviour, it seems to me that rim cross section is more important than rim height.


Thanks. I realize my c35s are not that different from the c24s, but I think I'll try this staggered setup anyways.


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## Mike T. (Feb 3, 2004)

walamt said:


> I decided on 38/50 as a compromise for cross winds. Out on a ride today even my 25mm rims with blade spokes , the wind was deflecting my front wheel.


I've been using 50mm rims f&r this year and have had a couple or three scary moments on 30-40mph downhills with crosswinds when vehicles pass and interrupt the crosswind. I'm considering going with something shallower on the front wheel.


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## DonDenver (May 30, 2007)

Mike T. said:


> I've been using 50mm rims f&r this year and have had a couple or three scary moments on 30-40mph downhills with crosswinds when vehicles pass and interrupt the crosswind. I'm considering going with something shallower on the front wheel.


Exactly. For those longer stretches up high out here (like coming down loveland pass) I'm happy with my c24's f&r with some idiots trying to pass me with a cross wind as I'm doing 50.


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