[scott_w]

> a narrower tire is going to usually be better, because you gain the aerodynamic advantage

Testing has shown this to not be true. Width is less important than overall shape of the tyre/wheel/bicycle interface when it comes to aerodynamics.

[ActorNightly]

Then everyone in the peloton for races like Paris Roubaix would be on 38c gravel tires. The reason they run 28c is because while it sucks for cobblestone, there sre flatter sections where the aero advantage is worth it.

Per 10mm tire width increase, you are getting 10 watts more aero drag at 25 mph.

[seadan83]

Elite riders and teams are very conservative. They shift to new tech after it has been proven over decades.

Consider that from a programming perspective, imagine using no tech newer than 2004.

The transition to 28s took a long time itself

> Per 10mm tire width increase, you are getting 10 watts more aero drag at 25 mph.

Interseting, where can I read more about this? I don't think this conclusion lines up with either the article, or the research from rene herse. Travel surfaced also matters quite a it, I could see that maybe being true in an idealized setting.

There is more to it. Tire needs to be in contact with ground to transfer power. A skinny high PSI tire will spend a lot of time bouncing. Just one example of how other real world factors can be more significant.

[scott_w]

Gravel tyres have higher rolling resistance. Also, beyond 32mm, you start risking cornering ability on the road as there’s more tyre to roll over to change direction.

Aero drag is just not that simple. You can’t, without testing, make the claim you’re making. Also, you can’t make the claim outside of the exact setup you tested. A different rider, wheels or bike could test faster on 40mm because aerodynamic drag is that difficult to predict.

[wiredfool]

Van der Pol won on 32mm tires this year, vs his normal 28mm.

32 also happens to be the biggest tire that fits in his Canyon race bike.

[ActorNightly]

You are right, this year 32c seems to be the most common. I remember 2023 was still 28c, and there were tests done that I remember seeing where 28c was slightly more efficient than 30c, but at a higher pressure.