The Detroit Diesel 5196687 main bearing set is an authentic OEM component designed for Detroit Diesel Series 50 and Series 60 engines. This specific set features a .030 inch undersize, indicating it is intended for crankshafts that have been ground down. Each bearing in the set includes a single oil hole to ensure proper lubrication within the engine. Manufactured to strict Detroit Diesel specifications, these main bearings provide reliable support for the crankshaft, contributing to engine longevity and optimal performance. This set is crucial for engine rebuilds or repairs requiring precise fitment for undersized crankshafts.