Shimano Disc Brake Adapter ISMMAF180PSA – Run a 180mm Rotor Up Front

Upgrading to a larger rotor for more stopping power? The Shimano ISMMAF180PSA is the precision-engineered adapter that bridges the gap between an International Standard (IS) fork mount and a Postmount (PM) brake calliper, allowing you to run a 180mm disc rotor on the front wheel. Lightweight, durable, and made from aluminium, it’s the small part that makes a big difference when you need confident, controlled braking on the descents.

Compatible with Shimano brake callipers BR-M535, BR-M585, and BR-M765, this adapter is a direct-fit solution for riders looking to maximise braking performance without changing their fork.

Key Features

Converts IS (International Standard) fork mount to PM (Postmount) calliper mount
Designed for 180mm front disc rotors
Compatible with Shimano BR-M535, BR-M585, BR-M765
Front wheel use only
Lightweight aluminium construction (50 g)
Colour: Black
Includes adapter and mounting bolts

Specifications

Brand: Shimano
Part Number: ISMMAF180PSA
Fork mount: International Standard (IS)
Calliper mount: Postmount (PM)
Rotor diameter (front): 180 mm
Position: Front / Fork
Material: Aluminium
Weight: 50 g
Colour: Black
Compatible callipers: BR-M535, BR-M585, BR-M765
Includes: Adapter + mounting bolts

Frequently Asked Questions

What does IS to PM mean?

IS stands for International Standard — a fork mount standard where the calliper bolts directly to the fork legs horizontally. PM stands for Postmount — a standard where the calliper bolts vertically to posts on the fork. This adapter converts an IS fork so you can use a PM-compatible calliper.

Which Shimano callipers is this adapter compatible with?

The ISMMAF180PSA is specifically designed for use with Shimano BR-M535, BR-M585, and BR-M765 brake callipers. Please verify your calliper model before ordering.

Can I use this adapter on the rear of my bike?

No — this adapter is designed for front wheel / fork use only. For rear brake adapters, please check our other brake adapter listings.

Does this adapter work with rotors other than 180mm?

This specific adapter (ISMMAF180PSA) is designed exclusively for 180mm rotors. Shimano produces different adapter models for other rotor sizes (e.g. 160mm, 203mm). Please select the correct adapter for your rotor size.

What is included in the box?

The package includes the ISMMAF180PSA adapter and all necessary mounting bolts. No additional hardware is required for installation.

How heavy is the adapter?

The Shimano ISMMAF180PSA weighs just 50 grams, making it a negligible addition to your bike’s overall weight.

Shimano Disc Brake Adapter ISMMAF180PSA – Front, 180mm, IS to PM, for BR-M535/585/765