When a part fails, it’s natural to look for the part number. It’s the first thing we do so a replacement can be ordered. But what if the number you see is hiding something?

ie; You see ‘MM9118WI’ on the outer race. You’re right in thinking it’s a Fafnir / Timken MPN, but Fafnir made multiple bearings with ‘MM9118WI’ in the MPN.