Brake Rotor/Disc

GM brake systems are identified by Regular Production Option (RPO) codes. For further information on RPO codes see Application and ID.

	RPO JN1, JN3, JB3*	RPO JN5, JN6*	RPO JN7, JN8*
Nominal Thickness	1.00	1.25	1.26
Minimum Refinish Thickness	0.979	1.23	1.23
Discard Thickness	0.964	1.21	1.21
Thickness Variation (parallelism)	0.0005	0.0005	0.0005
Run Out (TIR)	0.004	0.004	0.004