This term indicates generically all sliding bearings that are located in four-stroke engines equipped with a monolithic crankshaft. The conrod bearing is a type of bearing, very specific, which works in hydrodynamic lubrication regime, with the shaft of the crankshaft that floats within the bearing shell, supported by an oil film of consistent thickness, so as to maintain always separated micro asperities of the two surfaces. In this way the direct metal contacts are avoided, the friction is very low, as well the wear. The resistance to the movement is only that due within the fluid, so there is no scraping. The conrod bearings are constituted by a support structure in steel onto which an antifriction material is applied.