Shimano SMMA90F203PPM - Bicycle Parts, 203mm P/PM;

Whether you're trying to mount your 160mm rotor with an ISO or post-mount setup, we've got the right Shimano Disc Brake Adapters for the job. All you need is the skeleton key to understanding Shimano's admittedly byzantine model naming convention. SM-MA stands for Shimano Mount Adapter, so that'll be universal across models and can be safely ignored now that you're here. The rest of the model name is the important part. An "F" denotes front brake and an "R" denotes rear brake. The following number (160, 180, or 203) is, of course, the rotor size, with special parentheticals for 203mm rotor conversion. The final two initials respectively describe the caliper type and the frame/fork mount type with either a "P" (post-mount) or an "S" (ISO). To alleviate confusion, we've reiterated the front or rear specification at the back. To recap, model number SM-MA-F160, P/S Front is for the front brake (F), it accommodates a 160mm rotor (160), it holds a post-mount caliper (P), and it attaches to an ISO fork mount (/S).