what year did the unit-bearing change?

[jmaxj]

i'm curious in what year the uni-bearings changed i've been told that it was 91 but not sure, anyone know?

thanks

 

[Wayne Sihler]

84-89 tapered bearings
90-99-ball bearing
99-01-w/1 piece Cast rotor
Wayne

 

[jmaxj]

right on thanks