bicycle tire myths

Wider tires roll faster than narrower ones: Riders have argued for years that narrower tires – especially on the road – roll faster and are more efficient than wider ones when in fact, the opposite is true. According to Wheel Energy, the key to reducing rolling resistance is minimizing the energy lost to casing deformation, not minimizing how much tread is in contact with the ground. All other factors being equal, wider casings exhibit less 'bulge' as a percentage of their cross-section and also have a shorter section of deflected sidewall.

To test rolling resistance, tires are mounted on control wheels and applied to the rotating drum with hydraulically controlled pressure
How big a difference are we talking about here? For an equivalent make and model of tire, Wheel Energy claim the 25mm-wide size will have five percent lower rolling resistance on average – the supposed average limit of human detection – than the more common 23mm one. However, 23mm and narrower tires do still have the advantage when it comes to aerodynamics, and to a lesser extent weight. If you're selecting a tire for drag strip time trials, narrow is the way to go, but if you want a better handling tire for road racing and crits, go wider – particularly for rough road surfaces