Overdraft

I have 23mm wide aero wheels (Bontrager Aeolus Comp 5) that came from the factory with 25mm tires. If I put 28mm tubless on them will I negate the aero-ness of them?
Thanks for your thoughts!

surak

Depends on how close to the pointy-end you are speed-wise. You'll still get benefits from having deeper section rims, even if you were to use much wider knobby gravel tires. But if you need every marginal gain to win an ITT or town sign sprint, then sure, you'd possibly throw a few watts away at 40+ kph, since most road wheels are optimized for 25mm tires.

You might gain some back in decreased rolling resistance if you ride over less than perfect asphalt, so that's another trade-off to consider.

cxwrench

Don't overthink it.

Overdraft

thanks for the thoughts! it was more of a theoretical question as I am slow AF and just wanted to make sure I didn't get laughed out of the coffee shop if I did it...

rm -rf

That's only about 1.5 mm more width on each side of the tire. Sounds good to me.

burnthesheep

If not racing, who cares.

Depending on tire, overinflating even a matched tire can be 1 to 8 watts. Just the front wheel. Not including the rear.

I can imagine a 28 on a 23 costing at least 8.

Round to 10w and I figure that is likely 4 to 5% of the average BF member’s true hour ftp’s.

https://silca.cc/blogs/silca/part-5-...d-aerodynamics

yaw

My wheels are 27mm outer 19.5 inner and Trek delivers them with 25mm.

I threw away the Bontrager tyres and put 28mm GP5ks on to test, but they bulge out.

I put 25mm GP5ks on and they sit much happier now, with the rim marginally visible from the front profile.

I could not sense a comfort difference at 70-80PSI with tubes.

So I take the aero benefit and keep the 28 for the rear only.

GhostRider62

Totally depends on your speed. I unintentionally put a too wide GP5000 tire onto my narrow, aero front wheel. At 30-31 mph, it was cost me close to 15 watts measured. That is my TT speed (on a recumbent) At 20-24 mph, a 28 mm tire on a 23 mm rim might cost 2-4 watts as a guess, I have never measured it.

eduskator

You would technically lose some aero, but the reduced RR of the 28mm tires may compensate. To be calculated!

Iride01 

We'll be more worried how high your socks are!

Overdraft

dear god… there’s a sock height convention? *googles ‘correct bicycling sock height’*
someone should tell me how high to wear my socks or I’ll have to start a new thread!
it’s almost like if you’re out of a sport for 20 years things change when you’re away….

Mojo31

Sock height only matters if you shave your legs. And, neither matter if you wave.

Troul 

I'd say the slightly wider tire is going to net more advantages in the long run.

more likely to happen if your chain is not using that current month's egyptian wax.

Overdraft

I waved at a number of people on today’s ride and very few of them waved back…. I now realize I’m being ostracized for having the wrong damn chain wax!

Mojo31

Probably the wrong socks.