In real life conditions, wider is better for rolling resistance. A wider tyre will have a shorter contact patch with the surface it is rolling over compared to a narrow tyre. This shorter contact patch causes less deformation of the tyre, which in turn leads to less rolling resistance. Professional road racers have to balance between rolling resistance, aerodynamic drag and weight; a wider tyre may have less rolling resistance, but it will generally be heavier and if it becomes too much wider than the rim it is mounted on, will offer more aerodynamic drag. Comfort, which a wider tyre will also bring, is not a factor taken into consideration by pro riders, making them chose tyres relatively more narrow than most recreational users. Nonetheless, most pros now use at least 25mm tubulars for regular road races and up to 30mm tyres for races with cobbles or dirt roads.