tyre size / rolling resistance

bottom_bracket

OK, so apparently recent research has shown 25mm tyres to be both more comfortable and quicker than 23mm tyres right? So how come on the tour during the time trials the bikes have what appear to be 18-20mm tyres on? Is that just to reduce wind resistance, and the increased rolling resistance is something they live with?

alihisgreat

Pros use Tubulars

Tubulars of a given size eg 23mm have less rolling resistance than clinchers of the same size.

Therefore there is less need to go up in tyre sizes for rolling resistance reasons.

Secondly when travelling at higher speeds wind resistance is the dominant force... so 18-20mm tyres must make more of a difference against the wind to offset their higher rolling resistance?

sungod

rr for some clinchers is now better than for tubulars

main reason pros use tubs is they can still be ridden (carefully) when flat, and when weight matters the wheel+tyre combo can be lighter

Monty Dog

You're probably best asking Tony Martin why clinchers are so good for TTs...Pros are starting to run wider tubs e.g. 25mm to match the wider-section aero rims - the aero benefits from skinny tyres are very marginal at best plus you're more likely to puncture.