40mm ROAD tires - not mountain bike tires.
And yes, compared to "skinny tires" they are faster.
The sweet spot for the "fastest" for the pros on roads is still being debated but the pro teams are now riding 28mm and up (which would have been a huge fat tire not that long ago).
I am not a pro and i can keep up with any Saturday group on 40mm and the comfort is so so much better
Interesting.
Is the [normal] theory that rolling resistance is higher with fatter tires?
I guess I could see the opposite - a wider but shorter footprint might end up being less resistance.
That was the traditional view (fatter made higher rolling resistance) but tests prove that the opposite is true in the real world (ie not on perfectly smooth surfaces). Something to do with wider tires deforming better at the contact patch. The only advantage to a skinny tire is the aero of the frontal surface area but that is negligible especially with wider and deeper rims these days.
Lots and lots of published studies but traditions die hard
