Best rim ross-section for crosswind stability

[trailgumby]

I'm hoping I can ask for some advice.

I'm looking to build some ~50mm deep carbon wheels for a new bike. Typically I run 25mm Conti rubber, so will be looking at rims between 26 and 28mm wide.

For crosswind stability I'm wondering whether something like the teardrop rim profile in the image below or someting with a more more straightsided U shape is better for cross-wind stability.

[alanyu]

IME wide curved V (bontrager, LB AR46, etc, close to your image) has (much) better crosswind stability than U (old DT, 25-28 mm open mold U's), but I have no experience on extremely wide U such as Rapide since I ride rim brake. In tour test, RSL 62 (refined wide curved V) outperforms other wheels including DA C60 (wide curved V) = ARC 1100 (UV) = Zipp 454 (saw tooth) > metron 60 SL (wide U) > WTO 60 (moderate U) on the crosswind stability without losing much aerodynamics.

Also following the 105 rule (in short it's real tire width vs rim brake track/outer edge width) is important for stability. 5000 S TR is around 25 mm on 19c rim and around 26 mm on 21c rim, while 5000 TR is 1-1.5 mm wider.

edit: 5000 TL, not TR in the last

[warthog101]

I have 85mm token tubular over 10 years old.
Yep they blow around.
They are damn fast though so I just used to put up with it.
Have some 58mm zipp404 firecrest ~2015.
They blow around less but occasionally it is felt in gusty crosswinds.
I have some prime rr 50 v3 that are pretty cheap and very stable
https://road.cc/content/review/prime-rr ... set-285637
Tbh I dont notice them blow around at all and have well over 10k km on them.

The above are all rim brake.


As per the other forum we are on, I also have some Light Bicycle WR50 that are disc braked.
I currently have 32mm tyres on them that break the 105% rule.
I dont notice any wind steering there either.
They will get 28mm, on the front at least, when the rear wears out.

I do not notice the 2 50mm wheelsets but having said that, I am used to coping with wind steer and putting up with it.
At race speeds, deep carbon wheels are just so much faster, it is just something to be tolerated imo.

Yes more of a pita when not racing however.

[trailgumby]

I have 85mm token tubular over 10 years old...
... <snipped>
As per the other forum we are on, I also have some Light Bicycle WR50 that are disc braked.
I currently have 32mm tyres on them that break the 105% rule.
I dont notice any wind steering there either.
They will get 28mm, on the front at least, when the rear wears out.

I do not notice the 2 50mm wheelsets but having said that, I am used to coping with wind steer and putting up with it.
At race speeds, deep carbon wheels are just so much faster, it is just something to be tolerated imo.

Yes more of a pita when not racing however.

IME wide curved V (bontrager, LB AR46, etc, close to your image) has (much) better crosswind stability than U (old DT, 25-28 mm open mold U's), ... <snipped>

Also following the 105 rule ... <snipped>

Thankyou both, that's been very helpful.