Aerodynamic advantage with deep rim wheels: expirement.
Discussion
Due to the on-going debate over the aero benefits of deep section rims v's standard rims, I've decided to run an experiment to determine what the speed increase/watt savings there are between different dept wheels.
I'm looking to sanity check the following experiment to see if it is valid before I embark on this huge undertaking.
Firstly, I currently ride 66mm wheels & I have a set of 85mm front 95mm rear wheels coming in the next 2 weeks. The 66s are clinchers, the 90s are tubs but I think this shouldn't have much of an influence over the results if I keep the tyre pressure consistent.
I intent riding them on the same 40 mile circuit 20 times each. The circuit is out and back, is very flat: with only 206m of climbing (nothing steep)
With 20 data points per wheelset at the end, I should be able to graph avg power output v's avg speed. Some of the results will be influenced by weather conditions but with 20 data points each I can filter out the outliers.
Obviously I will keep all other parameters the same: same bike, tyre pressure, same clothing etc.
Is there anything I've forgotten? Does it make sense or am i just being silly
Is there too little of a depth difference between both sets of wheels to see a noticeable? ideally I should try a shallow rim v's the deep rims but unfortunately my only shallow rims are only used on the turbo. If it is a deal breaker I might try pick up a set of decent shallow rims.
I'm looking to sanity check the following experiment to see if it is valid before I embark on this huge undertaking.
Firstly, I currently ride 66mm wheels & I have a set of 85mm front 95mm rear wheels coming in the next 2 weeks. The 66s are clinchers, the 90s are tubs but I think this shouldn't have much of an influence over the results if I keep the tyre pressure consistent.
I intent riding them on the same 40 mile circuit 20 times each. The circuit is out and back, is very flat: with only 206m of climbing (nothing steep)
With 20 data points per wheelset at the end, I should be able to graph avg power output v's avg speed. Some of the results will be influenced by weather conditions but with 20 data points each I can filter out the outliers.
Obviously I will keep all other parameters the same: same bike, tyre pressure, same clothing etc.
Is there anything I've forgotten? Does it make sense or am i just being silly
Is there too little of a depth difference between both sets of wheels to see a noticeable? ideally I should try a shallow rim v's the deep rims but unfortunately my only shallow rims are only used on the turbo. If it is a deal breaker I might try pick up a set of decent shallow rims.
- I can't believe I spelled experiment wrongly in the title.* Sorry.
Edited by NitroNick on Monday 17th September 10:41
there are a good number of variances that you can not control. Weather, traffic, your own physical ability on the day and a whole host of other things but it seems plausible. Tubs roll faster too, the difference you measure at the end could simply be a result of the tubs vs clinchers and not the deeper rims.
As you get more comfortable with the deeper rims you may ride faster as a result of an increased confidence thus the benefits are indirectly attributed to the rims but more your own ability.
As you get more comfortable with the deeper rims you may ride faster as a result of an increased confidence thus the benefits are indirectly attributed to the rims but more your own ability.
I understand that there are factors outside my control e.g. the weather, but the more I repeat the experiment, the more consistant the results will become.
Plus I'm living in Phoenix for the next year so the weather shouldn't be a problem.
I would alternate the wheels daily to reduce the effect of the weather, plus the weight loss (i'm carrying about 3 kgs over race weight at the moment, which i'll lose over the next month to 6 weeks)
Plus I'm living in Phoenix for the next year so the weather shouldn't be a problem.
I would alternate the wheels daily to reduce the effect of the weather, plus the weight loss (i'm carrying about 3 kgs over race weight at the moment, which i'll lose over the next month to 6 weeks)
ChrisMCoupe said:
I would have thought this sort of data must be available already. I know Okgo mentioned somewhere there was a conclusion that aero are better on anything other than serious climbs. A good test never the less 
Surely what you had for breakfast that morning must come into it
The data is possibly out there somewhere but any of the studies i've seen have been conducted by wheel manufacturers and in all cases the wheels they manufacture are faster than their rivals.Surely what you had for breakfast that morning must come into it
There are 3 manufacturers at the moment claiming to have fastest deep section wheelsets: Zipp, reynolds and Enve.
With regard to the breakfast comment: I guess the only solution is to eat the same thing every morning.
NitroNick said:
daz3210 said:
Will the wheel/tyre combinations weigh the same? If not is that a contributing factor?
There will be very little difference in the wheelset weights.daz3210 said:
But how much will the little difference make? I have heard it suggested that the slime in (some) tubes meant to auto repair punctures can have an effect, and that must weigh next to nothing.
The course I will be using is pan flat so it should minimise the effect the difference in weight will have. Weight will have an effect on acceleration but with only one set of traffic lights and two junctions this shouldn't be an issue. http://www.rouesartisanales.com/article-15505311.h...
As you can clearly see this is not a brand new test, but you can still see than Zipp 404 are some way more aero dynamic than the brick-like Aksium. Dunno why we're arguing about it though really, the bloke is clearly trolling, and just because he can't see the advantage of his fancy kit I don't see why the rest of us should have to prove ourselves!
As you can clearly see this is not a brand new test, but you can still see than Zipp 404 are some way more aero dynamic than the brick-like Aksium. Dunno why we're arguing about it though really, the bloke is clearly trolling, and just because he can't see the advantage of his fancy kit I don't see why the rest of us should have to prove ourselves!
ChrisMCoupe said:
I would have thought this sort of data must be available already. I know Okgo mentioned somewhere there was a conclusion that aero are better on anything other than serious climbs.
I am waiting to hear why he says no one used them for the last day of the ToB.Any tests outside of the lab/wind tunnel will be fatally flawed and subjective.
If a test cannot be precisely and accurately replicated by someone else, then the data is meaningless.
Raven Flyer said:
I am waiting to hear why he says no one used them for the last day of the ToB.
Any tests outside of the lab/wind tunnel will be fatally flawed and subjective.
If a test cannot be precisely and accurately replicated by someone else, then the data is meaningless.
Any tests outside of the lab/wind tunnel will be fatally flawed and subjective.
If a test cannot be precisely and accurately replicated by someone else, then the data is meaningless.
Plenty of deep rims there....
Really? A couple of mid depth rear wheels, maybe. Perhaps I should have gone to Specsavers.
I watched it on the tele and even the gf (who cycles too) commented on the lack of deep section rims, particularly on the higher placed riders.
I guess you had to see their set ups on the flat routes to understand.
I watched it on the tele and even the gf (who cycles too) commented on the lack of deep section rims, particularly on the higher placed riders.
I guess you had to see their set ups on the flat routes to understand.
That is just one picture. There were a massive amount who were using aero rims of some description. Even JTL was using what looked like 40-50mm mavics on the final stage.
Of course they were not using 808's, but Cav and a few others in the sprints were using 50-60mm rims on the final stage.
I don't know what you're still arguing about really. But I guess you have to have actually ridden them to know that they're quicker most of the time.
Of course they were not using 808's, but Cav and a few others in the sprints were using 50-60mm rims on the final stage.
I don't know what you're still arguing about really. But I guess you have to have actually ridden them to know that they're quicker most of the time.
okgo said:
Dunno why we're arguing about it though really, the bloke is clearly trolling, and just because he can't see the advantage of his fancy kit I don't see why the rest of us should have to prove ourselves!
I'm not trollingIn my personal experience the "advantage" that deep rims have in the wind tunnel proves to be the square root of f
k all in the real world and not even a measurable difference - let alone one that you can say "yeah those wheels saved me 30 seconds on a 3km strava segment"kthx
itsnotarace said:
I'm not trolling
In my personal experience the "advantage" that deep rims have in the wind tunnel proves to be the square root of fk all in the real world and not even a measurable difference - let alone one that you can say "yeah those wheels saved me 30 seconds on a 3km strava segment"
kthx
And I've told you that the difference is easily measurable, myself, and other people in the club who user powermeters certainly can see from our times on various things from climbs of a mile or so (where I agree, the gains are small given distance)all the way up to 25TT's where the difference could be in the minutes quite easily.In my personal experience the "advantage" that deep rims have in the wind tunnel proves to be the square root of f
k all in the real world and not even a measurable difference - let alone one that you can say "yeah those wheels saved me 30 seconds on a 3km strava segment"kthx
Just because you don't notice it, it doesn't mean others don't. We're not all like you!
'kthnx' oh dear.
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