Originally Posted by
Russ Roth
There is a point where wider just adds more rolling resistance and enough extra weight to upend the whole thing not to mention any possibility of aerodynamics go out the window. For commuting a 1.2-1.4 tire is wide enough though I wouldn't go wider then 1.2 which is a 30mm tire and really after that things get slower and don't add much more to a commute then time.
This is not true. 'Rolling resistance', the energy lost to tire casing flex as you ride, is less for wider tires, if comparing otherwise identical tires. At higher speeds aerodynamics will play a part, especially if your rim is too narrow compared to the tire. And for climbs, the additional weight will play a part, although if the tires have identical construction then this will be pretty minor.. But
if tire construction is the same, wider tires have less rolling resistance.