A-1823482-AI Bearing Set, Main (.010")One New Aftermarket Replacement Main Bearing Set (. 010" Undersize) Fits John Deere Equipment This aftermarket replacement main bearing set is machined . 010" undersize to Fits John Deere engines with reground or worn crankshaft main journals. Main bearings support the crankshaft within the engine block and are a critical component in any engine rebuild or overhaul. A . 010" undersize set is used when the crankshaft main journals have been turned down