Aero data from 19 wheels by Hambini
Moderator: robbosmans
@hambini
Any chance you could take a crack at quantifying braking performance of the various wheels?
Any chance you could take a crack at quantifying braking performance of the various wheels?
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I have replied on the blog post but for completeness I'm writing the response here.refthimos wrote: ↑Mon Aug 20, 2018 11:33 pmI posted in the comments to the article, but on-rider testing is difficult, particularly if not using aero bars to really lock the test rider(s) into a replicable position. Even then, you have to be really cognizant/careful to replicate torso, head/neck, hands, etc.
Tire choice can also be very wheel-specific and it's not clear if each wheel was tested with its optimal tire. If all wheels were tested with the same tire, then some wheels were advantaged while others disadvantaged depending on if the chosen tire was a good choice for that particular wheel.
The rider was aligned with a laser. His hinges were "targeted" and then aligned with that.
And I take on board the comments about the tyres. They were all conti GP 4000S II. It is possible for some variation in there but changing the tyre changes more than one control variable.
Hambini
Hambini Aeronautical Engineer, Polluting YouTube since 2016 - views expressed are my own...
Would like to see how my 4.5s compare to 404s and the 3.4s...
SL8 S-Works Project Black - 6.29kg
IG: RhinosWorkshop
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I think the generalizations we can take from the results is that depth trumps profile but is pretty insignificant at "normal" speeds ~30kph between any mid-depth wheel. Judging from the performance of the 7.8s and the 3.4s, it seems to me that at 30kph the 4.5s would fall in the Shimano C50/C60 category at 185w and if you assume it also follows those same trends, it should be ~600w at 50kph, perhaps a bit under but in any case, I certainly wouldn't expect them to be faster than the 404s at all given that they're less deep (48mm/56mm versus 58mm/58mm) AND if you take the 3.4s as guideline, the ENVE profile may not be very fast for what it is (or costs).. but that's ignoring all the other things like ride comfort, stability, stiffness, braking performance, etc
That's the moral IMHO:
"In the bike industry, wheel aerodynamic testing has generally been conducted by two groups of people - Wheel manufacturers and journalists. Wheel manufacturers will usually adjust tests to make their particular wheels look more favourable than their competitors in testing. This is usually achieved by a combination of adjusting speeds and angles. The reality is this type of test is not impartial. Journalists on the other hand tend to visit their local university and ask some clever boffin to conduct their testing for them and give them the results or go to their local velodrome, hold a speed and see how much power the wheels consume. Both of the above testing methodologies are not representative of the real world."
So whenever a new 'scientific' test by a big manufacturer or a popular magazine comes up, just keep calm. Probably it is not that credible.
"In the bike industry, wheel aerodynamic testing has generally been conducted by two groups of people - Wheel manufacturers and journalists. Wheel manufacturers will usually adjust tests to make their particular wheels look more favourable than their competitors in testing. This is usually achieved by a combination of adjusting speeds and angles. The reality is this type of test is not impartial. Journalists on the other hand tend to visit their local university and ask some clever boffin to conduct their testing for them and give them the results or go to their local velodrome, hold a speed and see how much power the wheels consume. Both of the above testing methodologies are not representative of the real world."
So whenever a new 'scientific' test by a big manufacturer or a popular magazine comes up, just keep calm. Probably it is not that credible.
Time to buy some Bont 60s and remove the decals me thinks....
SL8 S-Works Project Black - 6.29kg
IG: RhinosWorkshop
IG: RhinosWorkshop
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hambini, any good idea where the HED Jet 6s lands?
I gotta say despite the very good deal on Yoeleo wheels, I very much still prefer alloy braking surface.
I gotta say despite the very good deal on Yoeleo wheels, I very much still prefer alloy braking surface.
At a guess it would be in the top third. As we are not funded in anyway, most of these wheels were donated from people we know/bike shops, I will see if I can get a set.
I'm going to add some more bits to that test about test protocols. Some of the individuals on Slow Twitch have questioned mine and my colleagues "Aerodynamic credentials".
Just to clear this up. The list of wants:
Lightcycle V and U profile
Farsports
Hed
Any others? I can't promise but I can certainly try.
Thanks
Hambini
Hambini Aeronautical Engineer, Polluting YouTube since 2016 - views expressed are my own...
I'm interested in all of those plus any of the newer Roval wheels (21mm internal models).hambini wrote: ↑Wed Aug 22, 2018 11:31 amAt a guess it would be in the top third. As we are not funded in anyway, most of these wheels were donated from people we know/bike shops, I will see if I can get a set.
I'm going to add some more bits to that test about test protocols. Some of the individuals on Slow Twitch have questioned mine and my colleagues "Aerodynamic credentials".
Just to clear this up. The list of wants:
Lightcycle V and U profile
Farsports
Hed
Any others? I can't promise but I can certainly try.
Thanks
Hambini
Hi Hambini,hambini wrote: ↑Wed Aug 22, 2018 11:31 amAt a guess it would be in the top third. As we are not funded in anyway, most of these wheels were donated from people we know/bike shops, I will see if I can get a set.
I'm going to add some more bits to that test about test protocols. Some of the individuals on Slow Twitch have questioned mine and my colleagues "Aerodynamic credentials".
Just to clear this up. The list of wants:
Lightcycle V and U profile
Farsports
Hed
Any others? I can't promise but I can certainly try.
Thanks
Hambini
Reynolds Aero 46 or 65 would be interesting for comparison as they are the only ones with a real teardrop shape.
In the Tour Mag. tests they were always some watts worse than the torodial shapes.
Regards,
Beaver
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