Originally Posted by
Nick Bain
I'm sure its true but its all about tradeoff. rolling resistance, aero, weight,
I'm also going to throw out there the theory that the ride is better on wider rims due to them being able to absorb bumps better since the tire is spread wider and the bump will push into the tire more so than it would on a rounder narrow tire in which the bump will force the tire to spread outwards. And I base this on absolutely nothing.
quite the run on sentence.
Wider rims change the profile of the tire. The tire is less able to absorb impacts and is more likely to pinch flat, but what you get in return is better handling in corners and a better aerodynamic cross section.
This is most apparent when you ride a MTB with narrow rims and fat tires, then switch to a wider rim with the same tire. The sidewall is more vertical and rolls less under lateral loads.
To put it simply, think of it like this: Holding a cup by its handle vs. holding a cup from its outside.