Swiss Side tests gravel wheel / tire setups for aero efficiency

Nothing too earth-shattering here, IMO…wider tires have more drag, as do tires with more knobs.

Based on these numbers, I’d say that traction and comfort are more important considerations for gravel than aero…again, not exactly earth shattering.

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Interesting that swiss side didn’t try to make a rim that met the rule of 105 for a 35-40mm tire. They were pretty strong in pushing that on the road side along with zipp. I would guess its just not practical.

This also confirms that some people who say their gravel bike on gravel tires are just as fast as road bikes on road tires are full of shit. Mine has always felt significantly slower for similar speeds and +39W they found is pretty in line with the magnitude I’m seeing

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I don’t know if they’re well suited for gravel, but I do know if you take a gp5k 32mm tires & put them on a FLO G700 gravel wheelset it’s very, very aerodynamic. If you are looking at a long day on chipseal that’s a good setup. For a day of bad tarmac there probably isn’t a better setup.

Also fast on the gravel but maybe not durable enough to be a true gravel wheelset. But super fast among wide wheels.

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This test looks like it’s comparing the aero drag differences between gravel tires, which to me is borderline useless. What I want to see is the difference between running a shallow gravel wheel vs a deeper aero wheel. Even if it doesn’t match the 105% rule. This is where I believe the aero gains matter. This test doesn’t seem to take rolling resistance between tires into account, correct?

Dont try that tire on a long gravel day. I learned my lesson

I would like liked them to compared numbers with

  1. see images attached below, deeper is better
  2. Wider wheel like 40mm external width and seen if it was more aero

If were all running a 25ID by 28EID whats its like with 30ID 40Eid. It should be a flush mount

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Did you click into the test on their website?

They tested their deep and shallow wheels

So 2-5W?

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This video is pretty cool regarding deeper wheels and wider tires.

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2-5W in a 200mile race is worth it in my opinion

No, that is what they did…go to the report itself, not the articel and you can see where they compared the 28mm rim vs the 42mm rim.

ETA- @cwiggum beat me to it!

Depends on a lot of other factors…the type of gravel, course, etc.

Some interesting data in that WinTunnel video…but the stinted dialogue is cringeworthy. :woozy_face:

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But…I feel better about sticking 32mm tires on my 31mm external 50mm rims :disguised_face:

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image

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would be helpful if SS posted measured widths for their tests since it can vary widely for a “35mm” tire

image

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did you pull those from the RR site? Sorry I didn’t click on that link since I don’t trust their RR for gravel tires

Ted King’s average when he won DK in 2018 was 19.2mph. So you’re much closer to the published 1.8w than you are to the 2-5 watts. 1.8w would hardly register especially since the margin of error for your power meter might be 1%, so at 200w your margin of error would be…higher than your “watts savings” between the Gravon 420 and Gravon 250

Lol, they tested these things at 45kph…how long do people average almost 28mph during a 200 mile gravel race? That seems awfully fast in the dirt.

How the hell did I miss that :joy:? I guess I didn’t click on the test and just quickly read the article. Not as much aero difference as I expected.

They don’t.

Maybe that’s the only way they can get measurable difference