bloodyshogun wrote:
BikeRadar just posted a video on their test of various deep section wheel. Wheels were tested with 1) Michelin Power 25mm
2) at 5 degrees, 12.5 degrees
3) on Orbea Ordu OMP with 3T Revo front end, KASK helmet
4) Rider does a lot of tests for 220triathlon / BikeRadar, seems able to hold power fairly consistent from ride to ride
5) Wind tunnel at University of South Hampton, with rider at speed, wind speed not specified
6) also subjectively tested for breaking (dry and wet), cross wind stability
They rated these wheels using a combined score (you'll see them in the youtube video), but I think 5 degree yaw angle drag is of most interest to us here and the results were:
https://www.youtube.com/watch?v=h0BH3wXzhrI&t=0s
I assume measure here in watts are with rider on board (5 degree yaw results only)
1) 373w: ENVE 7.8:
2) 374w: Zipp 808 NSW
3) 379w: HED JET Black 6/9
4) 380w: DT Swiss RRC 65
5) 381w: Knight 95
6) 386w: Progress Space
7) 388w: Vision Metron 55/81
7) 388w: Profile Design 78 24
9) 408w: Roval CLX64
10) 410w: Mavic CXR
EDIT: On 2nd thought, the unit might be grams of drag. Assuming the wind tunnel was running at 30mph, then 10g = ~1 watt. This seems more reasonable and makes the performance of each wheel much closer to each other
I was initially skeptical of the units listed, but, upon further review, it makes sense. Those are the "raw" numbers from the 30mph testing of they full wheel/tire/bike/rider system. Converting the numbers to 40kph, this test suggests it takes ~216 watts on the HEDs at 5 degrees yaw. That seems reasonable for full wheel/tire/bike/rider system exclusive of rolling resistance and drivetrain losses. What doesn't seem reasonable, however, is the suggestion that the CLX64s need 16 more watts to turn the same speed at 5* yaw. I've never seen the Roval test so poorly against its peers. The German Magazine "Procycling" velodrome tested a bunch of deep section wheels (unfortunately no HED, Enve, or Zipps), and the CLX64's essentially tied for the lowest drag. Tom A posted a lot of comparisons between HED Jet 6+'s and the CLX64s in various configurations (wheels/tires alone, wheels/tires/bike, and wheels/tires/bike/rider); in every configuration, and at every tested yaw angle, the Roval showed less drag. The only seemingly significant difference is the tires. Can a change of tires really be responsible for a 20+ watt swing in drag difference between two wheels?
"They're made of latex, not nitroglycerin"