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Equipment > Components > Brakes > Disc Brake Adapters / Small Parts

Description

Post mount standards define rotor size by the distance between the caliper mounting holes and the rotor centerline. A fork designed for 160mm rotors positions those holes 20mm closer to the axle than one designed for 180mm rotors. The Shimano SM-MA-F180P/P2 adapter bridges that gap, letting you run a larger rotor on a frame or fork built for something smaller. Mount this adapter to a 160mm post mount fork, and your caliper sits at the correct height for a 180mm rotor. The same adapter also works for 140mm post mount frames running 160mm rotors since the offset math is identical.

The P/P2 designation indicates this is the second-generation design. Shimano revised the shape for improved hose routing, which matters when you're trying to keep a clean line from lever to caliper without kinks or tight bends. The adapter itself is machined aluminum, stiff enough to maintain caliper alignment under braking loads without adding significant weight. At 20 grams, the mass penalty for running a larger rotor is negligible compared to the stopping power gained.

Installation requires removing your caliper, bolting the adapter to the caliper first, then mounting the assembly to the fork or frame. The included hardware accounts for the additional stack height. Once installed, you'll need to re-align the caliper to the rotor using the standard procedure: loosen the caliper bolts slightly, squeeze the brake lever to center the pads on the rotor, then torque the bolts while holding lever pressure. Shimano specifies 6 to 8 Nm for the caliper fixing screws.... Read More

Features

  • Post mount to post mount adapter for 180mm rotors
  • Converts 160mm post mount forks/frames to accept 180mm rotors
  • Also converts 140mm post mount to accept 160mm rotors
  • Second-generation design with improved hose routing
  • Works for both front and rear applications
  • Machined aluminum construction
  • Mounting hardware included
  • Caliper torque specification: 6-8 Nm
  • 20 grams