If Scope's fishscales for the 10-20% yaw band bring a 0.6W advantage over a ride, another design choice is hidden nipples (see https://wheellabkr.imweb.me/Blog/?q=YTo ... 52&t=board): "external nipples generate 0.5-0.9W of additional aerodynamic loss, which is not negligable compared to the marginal gain by "wider aero steel spokes" covered above. The reason why this small nipples make this relatively meaningful difference is that they are rotating on the outer part of a wheel rather than the central part." And hidden nipples are something that apply across all yaw bands, benefitting all of your ride rather than 20% of it. Hiding nipples is something Scope do, and Campag do with their Bora Ultras, so I'm surprised the Bora rather than the Bora Ultra was tested by CN, as 0.5-0.9W would have pushed all Campag's curves much lower down in CN's graphs. The same link notes "for the disc brakes, the front hub and spokes should transfer the braking torque [...] this requires more front spokes [...] lots of road disc wheels now uses 20 or 24 pcs of front spokes instead of 16 to 18 for rim-brake wheels". This is another Bora Ultra design choice, the G3 spoke pattern puts twice as many spokes on the front braking side, and twice as many on the rear drive side (braking force less of an issue on the rear), to allow for 21/21 rather than the 24/24 of the Boras. This would further improve the numbers for Bora Ultra in the CN charts.
However, when you look at the wattage improvement possible between rides on a home trainer, via focussed mental and physical attitude, then discussing 1 or 2W differences across a range of very expensive wheels is faintly ridiculous. But here we are..
CN big aero wheel test
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Well it's all relative, and as I say faintly ridiculous. The Scope fishscale wheels are £4,000, where the fishscales provide just 0.6W over a ride. With current UK discounts Bora Ultras are £3,000, where the hidden nipples give 0.5-0.9W, so you decide what's worth it or not. To use yet another Scope graph (https://www.scopecycling.com/wp-content ... 6x1366.jpg), which puts the differences in Watts rather than CdA, all we're talking about is 1 or 2 watts in total across all these wheels, so maybe none of it is worth it. Although Nereth points to the known difficulties with stability of 80mm+, instead of dancing on a pin spending more and more money to gain improvements on 60mm wheels, invest instead in 80mm or disc if you want a real speed improvement: viewtopic.php?f=132&t=172719&start=15
If you look at the Granfondo test the spread is a bit bigger: https://granfondo-cycling.com/best-roadbike-wheels/
At 45 km/h the difference between the fastest wheelset and the slowest is about 10 watts (so indeed, at 30-35 km/h most amateurs ride it will be much less).
At 45 km/h the difference between the fastest wheelset and the slowest is about 10 watts (so indeed, at 30-35 km/h most amateurs ride it will be much less).
Lightweight (as their name suggests) have a focus on weight, so their 101 watts is an outlier in that study that should probably be discounted. And I'll omit Mavic's cosmic and DT Swiss ERC because their not part of the CN tests. That leaves a range of 91.89 - 95.43, granted that's a 3.54W range, but still peanuts. Different testing methods will inevitably result in different results, but this thread is about the CN 18 wheelset test.
Also, 20mph (32kph) into a 10mph wind (16kph) is a 48kph problem most riders will encounter.
Also, 20mph (32kph) into a 10mph wind (16kph) is a 48kph problem most riders will encounter.
They are not part of the CN test, but it's still interesting to see in the CN test and other tests such as the GF one what parameters of wheels seem to do well and not well. The Lightweights have an 18mm internal rim width and an 19mm (!!) external rim width. They tested with 28mm GP5K's, so these must have bulged completely over the rim likely accounting for the big difference with the other wheels. (but still, even with a ridiculous 19mm ext width the difference with the top spec wheels is 'only' 10 watt).HiFi wrote: ↑Mon Dec 02, 2024 6:23 pmLightweight (as their name suggests) have a focus on weight, so their 101 watts is an outlier in that study that should probably be discounted. And I'll omit Mavic's cosmic and DT Swiss ERC because their not part of the CN tests. That leaves a range of 91.89 - 95.43, granted that's a 3.54W range, but still peanuts. Different testing methods will inevitably result in different results, but this thread is about the CN 18 wheelset test.
Also, 20mph (32kph) into a 10mph wind (16kph) is a 48kph problem most riders will encounter.
I didn't read the test, so I'm ready to get flamed but...as I remember it, tunnel tests are fine. But the signal/noise ratio is way above real world conditions, and one of the key metrics is how well/quickly airflow reattaches in transient/outside conditions. Did/can the test take this into account? Seems to me that's where the real benefits lay, in that the delta between best and worst in lab conditions is only a few watts. Maybe the view is that they can't effectively test that in a standard tunnel, but a larger stall angle is a reasonable proxy for greater flow stability across the rim.
