What does the SRAM 20mm Flat Mount Disc Brake Adaptor do?

The SRAM 20mm Flat Mount Disc Brake Adaptor is used to mount a flat mount caliper on frames and forks that require a 20mm offset, specifically to fit a 160mm rotor on a rear flat mount frame that is designed for 140mm. This adaptor shifts the caliper position to accommodate the larger rotor without requiring a post mount adaptor. It's a clean, low-profile solution for upgrading rotor size on flat mount road and gravel bikes.

Before ordering, confirm that your frame and fork can accept a 160mm rear rotor and that a 20mm flat mount adaptor is the correct fitment for your specific setup. Refer to your frame manufacturer's specifications for minimum and maximum rotor sizes and adaptor requirements.