Originally Posted by Mtracer

GCN just dropped a video where they compared the same tire model (Pirelli P Zero's I think) at three different widths (26, 30, 35 mm, I think) on the same bikes and same wheels. They also did three different power levels (100, 200, and 300 W) so a good range of speeds.

They did it on an outdoor closed track with what they said was very smooth pavement. They found no significant difference in speed. And in fact the widest 35 mm tires were the fastest, though just ever so slightly.

Of course, it's a small data set, but even they were surprised that the wider tire, at appropriately lower pressure, wasn't slower given the smoothness of the surface. But then again, even smooth pavement, isn't really that smooth.

I think they did note they thought the wider tire didn't handle crosswind as well, likely due to the airflow not being as smooth around the tire, given it was wider than the rim.

This is just another one of these types of videos I've seen lately that seem to show essentially no penalty for running wider tires. There's of course an upper limit, and as mentioned in this thread, wider rims and tires are going to be a little heavier.

I'm currently waiting until I wear out a set of GP 5000 S TR 28 mm to try some 32 mm. But these damn GP 5000's just don't want to wear out. I have 2,700+ miles on the rear tire, and the wear indicators are still very visible. I'm not sure I've ever gotten this many miles out of a rear tire. Though often it is the cuts that do them in rather than gradual wear.