This invention relates to a device (10) for loading a motor of a road vehicle. The device (10) includes a pair of vehicle drive wheel support rollers (12, 14) arranged in tandem about parallel axes (16, 18). The device (10) further includes drive means drivingly interconnecting the rollers (12, 14) to control rotation of the rollers (12, 14) relative to each other to be in the same direction and at a predetermined, peripheral speed ratio unequal to 1:1. When driving the rollers (12, 14) via a drive wheel of the vehicle, the discrepancy in peripheral speeds between the drive wheel and at least one roller (12, 14) causes drag and thus loading the motor. The invention extends to a method of loading a motor of a road vehicle, and also to an arrangement for loading a motor of a road vehicle.