Two sets of bicycle tyres were tested with a one-degree-of-freedom two-wheeled pendulum, a portable rolling resistance test bed. Vertical load affected the rolling resistance coefficient only in a minor matter. The wider tyre showed an about 10% lower rolling resistance coefficient in comparison to a narrow tyre of the same type. Tyre inflation pressure and temperature are the major influence factors for rolling resistance. Both of them affect with factor two to three in the relevant range. Based on the data about temperature and inflation pressure a simple model was suggested.