Originally Posted by Wilfred Laurier

Contrary to racer orthodoxy, the main difference between narrow tires like 25mm wide and 'normal' widths like 32 mm wide is usually weight, which only makes a difference on climbs and during acceleration, and a slight improvement in aerodynamics at higher speeds. But the wider tires are superior in almost every other way, including control, comfort (allowing longer and harder efforts due to reduced fatigue), and often rolling resistance. But the rolling resistance is often overstated as it is a very small part of the energy equation when you get over ~15 mph. The problem most people have with wider tires, and the reason why they feel a difference when switching from 35mm tires to 23 mm tires is that they are not using the good quality road tires, but heavy thick hybrid tires.