Disclosed is a lawn mower device having a drive configured to rotate a shaft in a first and second direction. A drive wheel is coupled to the shaft and is coupled to a driven wheel by a drive belt. A tensioning system is shown coupled to the drive belt. The tensioning system has a first idler plate configured to bias a first idler pulley against the drive belt when the drive is rotating the shaft in the first direction and a second idler plate configured to bias a second idler plate against the drive belt when the drive is rotating the shaft in a second direction. A brake mechanism is further coupled to the tensioning system. The brake mechanism is configured to resist the rotation of the driven wheel.