... bulldozer undercarriage parts and auto parts,including track roller,top roller,track chains,idler groups,roller,bushings and pins, ... factors affecting travel life of products.These supporting rollers provide maxmimum rigidity when other components are mantled in machine. ... Line Capacity Actual Units Produced(Previous Year) Track roller, Top roller, Track rim, Idler, Track link, Cylinder USD 1,580,000 ...