I have the 72/72 set on my P3 and use them for all my training rides. I never feel a steering moment, even with side gusts. What I do feel when it's gusty is a slight lateral push on my whole bike that makes me involuntarily lean slightly into the wind, but that is a stable reaction and isn't alarming.

Unstable would be if it caused a steering moment that made your front wheel point away from the wind, because then it would get worse as your wheel becomes more perpendicular to the wind due to a disturbance. From a side force perspective, an unstable situation would be created if a side gust created a "lean away from the wind" response, which would mean that you'd have to drift with the wind.

I haven't ridden other deep wheels, but as far as I can tell it's no worse in cross winds or gusts than non-aero Bontrager Race-X lite wheels with aero spokes that I used to ride, but certainly faster.

Thought I'd interject something a little different. I just installed a set of 62 Strikes with a wheel builder disc cover for the rear on my P3 and have not had any issue with cross wind or quartering winds. I've only ridden them four times. Two TT's and a couple pre race rides, but so far I'm nothing but pleased with the set up.

We've actually been testing the Reynolds stuff in the wind tunnel as a stand alone wheel, and have found they are very good in no wind conditions, but in the windy conditions the aerodynamics are not as good. That being said, everybody I have talked to has raved about the crosswind handling, so that is a plus.

But we have found with when the yaw angle goes above 5 degrees, our new 44mm depth does better than the sharp 58mm depth.
We have a full white paper coming out soon about all of this.

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http://www.boydcycling.com Handcrafted Revolution

Thanks for the data Boyd! I remember seeing another test on the Reynolds rims and the conclusion was similar. What tire was used?

Cross wind handling. Hard to believe the Reynolds would be good because the leading and trailing shapes are so different. Do you measure side force or lateral torque in the tunnel?

I have the 72/72 set on my P3 and use them for all my training rides. I never feel a steering moment, even with side gusts. What I do feel when it's gusty is a slight lateral push on my whole bike that makes me involuntarily lean slightly into the wind, but that is a stable reaction and isn't alarming.

That's exactly how I'd describe the generic 86mm rim I've been using on the TT bike. No handling problems whatsoever. Gusts are tricky and highly variable, so I can't say for sure at this point, but so far the handling seems way better than the old Zipp 808 clincher I used previously.

We used the same Conti GP4000 SII in both a 23mm and 25mm for all runs with all wheels.

A2 wind tunnel used to have a measurement called Center of Pressure that basically told how well a wheel would handle in crosswinds. The last time I was there they mentioned that it still needed some tweaking and they were not including it in the data reporting anymore. . . so we don't have that info.

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http://www.boydcycling.com Handcrafted Revolution

interesting, thanks coachboyd.
reynolds own testing shows something kindof similar - compared to the enve 6, the rc 58 suffers from 5 deg yaw out until the enve stalls and the reynolds wheels seem to get a real boost at wider yaws. the real interesting thing about the reynolds whitepaper is that their wheels do particularly well in the full bike+rider tests - staying more or less equal with the enve 6. perhaps the more turbulent environment is more favourable to their shape which would make some sense since there seems to be general agreement that they are less affected by side forces. or being cynical maybe there are more variables at play, allowing them to find a configuration where they win. it is these tests where the reynolds 72 shows a big gain over their 58 too. paul lew's talk about their wheels being low drag, low lift compared to the higher drag, higher lift of the more rounded shapes would seem to match this - lift will be reduced in the more turbulent air around a full bike+rider compared to a wheel exposed to a clean crosswind so the comparison becomes low drag, low lift vs high drag, low lift

i think the clear thing from looking at aero test results is that the differences between any of the recent higher end wheels of similar depths are pretty small - possibly meaningless given the combination of margin of error and specifics of a given test scenario

I rode all my PRs with either Aero 90s or Aero 72s. Both handle very well in crosswinds.
An Aero 72 is a bit easier to change a tire.
Apart from being stable and aero, they also have super hubs and are very strong (compared to other brands I used in the past).
You wont regret either choice, 72 set or 90 set.
Sam Gyde

I hope I can help with some understanding. The large-radius spoke face shapes tend to generate a higher lift "L" values (and also higher drag "D" values) in reference to L/D ratios in winds 30 - 50 KPH. These shapes rely on high wind energy (high-velocity environmental blowing wind) to perform. 50 KPH+/- has been typical wind tunnel wind velocity range for years. Most of the ST community knows I’ve spent a significant portion of my professional career in wind tunnel testing, and most of my published research data is based on 40 – 50 KPH wind velocity range. However, with the development of the DET airfoil shape I have become more interested in a different range of wind conditions 5 – 30 KPH wind velocity. Most athletes relate to wind tunnel wind velocities of 40 - 50 KPH because this is the velocity elite athletes race their bicycles. However, this wind tunnel wind velocity can be confusing. At zero degrees yaw 40- 50 KPH wind tunnel wind velocity mimics the velocity of elite cyclists. At other yaw angles 1 degree – 90 degrees, the wind tunnel mimics the blowing wind (not the cyclists’ forward velocity). This means there may be a good reason to test a cyclist at two different wind velocities. V1, which corresponds to zero degrees yaw and V2 which corresponds to all other yaw angles. With V2 we have tested at real world speeds that are attainable by athletes in common wind velocities of 10-30 kph (for reference, a windy day at Kona winds are steady 15 kph gusting to 30 kph, not 50 kph). Therefore, we look at how wheels perform under conditions that are possible for athletes to experience given the limitations of the human engine and its performance under the duress of real-world wind. With that said, the an earlier post of a white paper (reference page 15) explains why yaw angles above 5 degrees are uncommon for elite athletes, and at 45kph bicycle velocity in 5 kph wind yaw angles over 6 degrees cannot be reached.
http://www.reynoldscycling.com/...%20Version-final.pdf
More data to come regarding the testing relating to V1 and V2 wind speeds and angles.​ -Paul Lew

I wonder if the steering axis was ignored and invalidated data measured purely as a Z-axis moment, as it would be coupled with other forces and moments (it probably behaves like a universal joint, with gyroscopic complications), including the mounting hardware aerodynamics. It seems that you'd need a torque-free setup for the front wheel and you'd have to measure a steering torque within the steering tube to do it properly, among other things.

As far as gyroscopic reactions to aerodynamic forces go, reactions occur with a 90 degree phase delay. If the center of pressure is dominantly fore/aft, it results in a rolling moment; a lateral force on the front of the wheel will result in pushing the bottom of the wheel out in the direction of the wind, which is probably the stable reaction I alluded to earlier. If the center of pressure is offset vertically from the wheel center, it will result in a yawing moment, unstable if high, stable if low, neutral if centered.

I don't believe that oval sections, or dimpling, represent optimal wheel geometry. So, until I can test wheels myself, my preference is for the Aero line. The caveat here is that I haven't tested any wheels myself, and I'm not involved in their design (though it would be fun to dive into).

thanks Paul, always great to get product engineer types involved in discussions here. yes, i've always found it a bit unclear the way apparent wind velocity changes with yaw and hence the curves on aero tests are maybe not representative of reality but so illustrate differences in aero performance between components so will be interesting to see how you are able to represent that

would love to get your input on the differences in comparative results between standalone wheel and bike with rider tests

Stand Alone Wheel vs. Bike with Rider testing can reveal interesting results. Frame and rider certainly influence the performance results. Initial wheel selection can be based on wheel-only evaluation, but when seconds count, athletes should consider final selection based on specific bike + rider + estimation of race speeds and wind speeds. I've seen similarly performing wheels in wheel only tests change order from best performing to second or third best performing when tested as part of a bike with rider. I won't discuss tire selection in my comment, but tire selection, and in particular tire diameter is a significant influence. Additionally,I have witnessed high lifting force (side force from wind) introduced tire scrubbing which added as much as 20 watts of rolling resistance for the bicycle (front + rear)!

Additionally,I have witnessed high lifting force (side force from wind) introduced tire scrubbing which added as much as 20 watts of rolling resistance for the bicycle (front + rear)!

Do you think that's why the low aero drag at high yaw measured in the tunnel does not translate onto the road? Based on tunnel tests we should all be faster in a cross wind.

The tire scrubbing is responsible for losses-- yes. The other explanation (and discrepancy) is that wind tunnel testing typically evaluates wheel lift based on 50 KPH+/- wind velocity. Rarely do athletes cycle in 50 KPH wind conditions, and in those conditions a 90 mm deep wheel/ rear disc wheel are not a good option). In the real-world lift is generated based on lower wind velocities such as 5 and 10 KPH, and the lifting force may be less at lower wind velocities. This is the basis for my investigation into wheel performance at lower wind velocities. I'll sign-out from this thread now... I'm heading to the annual Eurobike show in Germany. --My best in cycling to ST athletes!