Shimano - XTR SM-MA90 Adaptor Postmount to Postmount Brake
Adaptor to use a larger brake disc in combination with a Postmount fork or frame and a Postmount brake. The included washers are surface-treated (silver) and will not rust. The wire is used to fix the screw. The adapter can be used as follows:
fork with 140 mm mount:
SM-MA90-F160P/P for the use of a 160 mm brake disc
fork with 160 mm mount:
SM-MA90-F180P/P for the use of a 180 mm brake disc
frame with 140 mm mount:
SM-MA90-F180P/P for the use of a 160 mm brake disc
frame with 180 mm mount:
SM-MA90-F203P/P for the use of a 203 mm brake disc