The clean grain elevator chain speed is measured by the low shaft speed monitor.  With the chain RPM and the force of the grain on the impact plate, the grain flow rate is calculated.  This measurement is recorded by the controller software in the combine.  For little to no grain loss it is important to have solid, non-worn rubber paddles.  Our clean grain chains are all made to O.E.M. Specs and all our rubber paddles are bolted to heavy-duty roller chain using locknuts.