Why wide | DT Swiss

30 MM INNER WIDTH
LESS ROLLING RESISTANCE

Cross Country wheels are made to be fast and this makes it necessary to reduce resistance where possible. On a rough surface, rolling resistance can be up to 69% of total resistance.

Rolling resistance is defined as: rolling resistance coefficient x weight x gravitational acceleration. Whereas the coefficient is defined by the wheel size, tire section, tire characteristics, tire pressure, tread, soil.

While most of those factors cannot be influenced by the wheel, we can modify the tire support.
A wider rim provides improved tire support which allows lower pressure and leads to less rolling resistance on rough tracks.

HIGHER TIRE SUPPORT
ALLOWING LOWER PRESSURE

During cornering, lateral forces occur which act on the tire. The contact patch of the tire moves in the opposite direction to the lateral force.

When riding through a corner with a narrow rim, the contact patch of the tire is no longer above the flange of the narrow rim. The tire is no longer supported by the rim and folds, resulting in an unstable riding experience. This folding creates tension over the tire which pulls on the opposite bead and causes a loss of air between the tire bead and the rim bed, so called tire burping.

The tire contact patch of the wide rim is inside the rim flanges. The side wall of the tire is supported by the wide rim which increases control. A wider rim can therefore be ridden with lower air pressure than a narrower rim.

LOWER AIR PRESSURE
LESS ROLLING RESISTANCE

A wheel with low tire pressure will roll better over rough surfaces than a wheel with high pressure, as the tire can adapt better to the ground. A wheel with high air pressure cannot absorb obstacles and the bike must move upwards, comparable to lifting work, which increases rolling resistance. Less air pressure leads to less fatigue, because as a rider you also have less lifting work to do.