Deep Rear, Shallow Front

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Most wheelsets today are equal depth or a staggered depth with the front being minimally more shallow than the rear.

I'm tired of high-speed descents on exposed terrain being ruined by unstable air. Despite the very real downsides of shallower wheels, I'm considering a set of shallow wheels. Crosswind only upsets my front wheel. I wonder about a nice deep rear wheel paired with a shallow front wheel. Is anyone here running a combo like this? If yes, how are you getting on with it?

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[ridenfish39]

I had a 35 mm front wheel handy for windy days when I had my System Six. I loved that bike but it was downright dangerous going downhill fast when it was blowing hard.

[Nohands83]

I considered picking up a Bontrager RSL37 front for windy days when I brought my set of RSL51s but I've not found the need yet as the 51s are super stable. Not all wheels are the same in this regard.

Aesthetically I think a difference larger than a 10-15mm starts to look pretty odd. How shallow are you thinking? What's your current wheels?

[req110]

The most terrifying event I had was a descent on my former systemsix with knot64s on Fuerteventura with sidewinds 40kmh...

But with 40s you will be fine.

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I considered picking up a Bontrager RSL37 front for windy days when I brought my set of RSL51s but I've not found the need yet as the 51s are super stable. Not all wheels are the same in this regard.

Aesthetically I think a difference larger than a 10-15mm starts to look pretty odd. How shallow are you thinking? What's your current wheels?

CRW 50 / 60 now. I've tried 3 different front wheels of similar depth with varying but similar results. On days that I expect to encounter wind or do long exposed descents, it seems like it might be nice to have something shallower. Am toying with the idea of having a 35 or 40 to keep around. I'm not as concerned about aesthetics as I am about being stable when I need it most.

[claus]

I'm riding a completely mismatched combination when it's windy: a very shallow wheel in front and something pretty deep in the back.
With gusty winds and a total weight around 60kg it is way too dangerous for me on these narrow mountain roads to ride the matching deep front wheel (though it's more fun when there is "no" wind!).
I don't care about the looks - I want to enjoy the rides.

[kode54]

I’m not concerned much about looks either, safety first. I’ll pull a shallow wheel for my Enve 4.5. Something like my LB AR25. I’ve had too many instances where the wind gusts moves the front in to the point that I felt unsafe. If anything, I avoid taking a light climbing bike as well and use my winter bike even during summer since I swap out my climbing wheels AR25 with shallow depth rim. The weight of the bike helps as much as the shallower rims.

[Lina]

I considered picking up a Bontrager RSL37 front for windy days when I brought my set of RSL51s but I've not found the need yet as the 51s are super stable. Not all wheels are the same in this regard.

Aesthetically I think a difference larger than a 10-15mm starts to look pretty odd. How shallow are you thinking? What's your current wheels?

CRW 50 / 60 now. I've tried 3 different front wheels of similar depth with varying but similar results. On days that I expect to encounter wind or do long exposed descents, it seems like it might be nice to have something shallower. Am toying with the idea of having a 35 or 40 to keep around. I'm not as concerned about aesthetics as I am about being stable when I need it most.

I'm genuinely curious how. 20 m/s gusts are somewhat common where I ride and I've never experienced much problem with any decently U-profile wheels.

[RadB]

Also depends on the bike to some degree. For example, imo Giant specced the previous model propel with mullet wheels due to a flexy fork and tob tube that precluded anything larger on the front. Actually current model is standardised at 50mm across the range now, so not sure if that supports or opposes my point, or if the frame is still flexy

[Nohands83]

There's lots of factors that contribute, it's not just wheel depth and/or rider weight - though both are for sure big ones but it's not as simple as that.

As the other poster said bike weight does make a difference, but so does fork shape (and it's interaction with certain wheels), bike frame shape, tyre width (in relation to rim), and even the geography of where you ride. Rider confidence and descending ability does also play a part as well.

For reference, I'm 80kg and 185cm so I'm not small, but certain bike and wheel combos have been terrible for catching the wind even at my weight.

[JHeiro]

I've been using many combinations of shallow front, deep rear, for the exact reason of reducing crosswind instability.
Currently have a Zipp 353 / 454 combo on my Enve Melee. 10-15mm difference in depth doesn't look bad aesthetically, but a 353 / 858 looks odd. Zipp 404 / 808 combination works fine as well.

[Hexsense]

Switch SuperSix Evo gen 3
To SystemSix
Then To SuperSix Evo gen 4.

SystemSix get pushed noticeably more than both SuperSix despite being heavier. The deep frame tube catch wind and do sailing effect to make the bike faster. That sailing effect have side effect in making the bike lean more into the wind as well.

I think I read it a long time ago that a deeper rear wheel make the whole bike more stable by getting tail out force counteracting the turn from front wheel. Wind pushing the whole bike sideway is much easier to manage than turning the front end only to steer toward the side. Obviously, this have a limit. If you go full disc rear and get hurricane level wind the bike might want to lean into the wind at a too deep angle that the bike tip over.

Other than shallower wheels, consider Wavy one as well. Like Light-Bicycle AR375, Light-Bicycle AR465, Princeton and Zipp whale wheels.

[Nohands83]

I've heard that as well about a deeper rear helping stability, but mainly it was about rear disc wheels so expect you would have to go pretty deep to feel the benefit.

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I'm on a TarmacSL7. Enve4.5 (2022), RapideCLX, and CRW5060 all produce instability for me under the same conditions. In this regard, the Enves are the worst, while the CRW and CLX are pretty comparable to one another.

It is the wind-induced steering input at the front wheel that drives me crazy. At 80kg I'm not being pushed sideways very often.