A straw chopper for a combine includes a rotor mounted in a housing with blades on a rotor for chopping the discharge material onto a material spreading assembly. The rotor is driven by a drive transmission from an output drive shaft of the drive system of the combine harvester including first a right angle gear box connected to the drive shaft, a second right angle gear box connected to the rotor and a single drive shaft communicating drive from the first gear box to the second gear box. One end of the rotor is supported by a shaft of the second gearbox carried on the combine housing. An adjustment is provided at the output shaft or at a gearbox to remotely from the cab adjust the speed of the rotor. The drive transmission includes a cogged timing belt for positive drive for increased power.
