Tapered Timken bearing
 

Do tapered Timken rear wheel bearings only work on pre 2000 wheels? "Timkin bearing #LM11949" Can anyone tell me if this bearing will work on a 99 FXD or a 2000 Fatboy

Most if not all of the twin cams had sealed bearings. The outer races are a little larger in diameter that the Timken bearings but the axles are the same size. So do you want to replace the later sealed bearings with Timkens? Usually people want to go the other way and replace the timkens with sealed bearings.