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