SRAM/Avid Disc Brake Adaptor – 40mm IS Mount, 200mm Front / 180mm Rear

IS (International Standard) Frame/Fork | Post Mount Caliper | +40mm | Includes Stainless Bolts | Black

This SRAM/Avid disc brake adaptor allows you to run oversized rotors on older IS (International Standard) mount frames and forks using a post mount caliper. Specifically, it steps up +40mm to accommodate a 200mm rotor on the front or a 180mm rotor on the rear — sizes commonly used on aggressive trail and enduro mountain bikes that need more braking power. Compatible with all SRAM and Avid post mount brake calipers, and includes the necessary stainless steel mounting bolts. A simple, reliable piece of hardware for upgrading rotor size or replacing a lost/damaged adaptor.

Understanding Disc Brake Mount Standards

There are two common frame/fork disc brake mount standards on mountain bikes: IS Mount (International Standard, also called 51mm IS) is the older standard found on many pre-2010 frames and forks, with two mounting holes set 51mm apart on a horizontal plane. Post Mount (74mm) is the more modern standard with two vertical mounting bolts. Adaptors like this one bridge the gap between the two, allowing a modern Post Mount caliper to be fitted to an IS Mount frame or fork, while also stepping up to a larger rotor size. The "+40mm" refers to the rotor size increase the adaptor accommodates relative to a direct-mount position.

Key Features

• Mount type: Converts IS Mount (51mm International Standard) frame/fork to Post Mount (74mm) caliper
• Rotor size: +40mm step-up — suits 200mm rotor (front) or 180mm rotor (rear)
• Includes: Stainless steel caliper mounting bolts
• Colour: Black
• Brand compatibility: All SRAM and Avid post mount brake calipers
• Genuine SRAM/Avid hardware — OEM quality fitment and finish

Specifications

• Brand: SRAM / Avid
• Frame/Fork Mount: IS Mount (International Standard, 51mm)
• Caliper Mount: Post Mount (74mm)
• Adaptor Size: +40mm
• Rotor Compatibility: 200mm Front / 180mm Rear
• Colour: Black
• Hardware Included: Stainless steel bolts
• MPN: 00.5318.009.003
• UPC: 710845714542

Compatibility

✓ COMPATIBLE WITH:

• Frames and forks with IS Mount (International Standard / 51mm IS) disc brake tabs
• All SRAM post mount brake calipers (Code, Guide, Level, DB series, etc.)
• All Avid post mount brake calipers (Juicy, Elixir, BB7, etc.)
• 200mm rotors on IS front forks
• 180mm rotors on IS rear frames

✗ NOT COMPATIBLE WITH:

• Post Mount frames/forks — this adaptor is specifically for IS Mount frames; if your frame/fork is already Post Mount, you need a Post-to-Post adaptor instead (e.g. SRAM MPN 00.5318.007.003)
• Flat Mount frames/forks — flat mount is a road/gravel standard requiring a different adaptor type entirely
• Shimano-specific adaptors — while Shimano calipers also use post mount, always confirm bolt spacing and caliper body dimensions match before mixing brands
• Smaller rotor sizes — this +40mm adaptor is sized for 200mm front / 180mm rear only; different rotor sizes require different adaptors

⚠️ Important: Always confirm your frame or fork's mount standard before purchasing. Check for "IS" or "International Standard" in your bike's documentation, or look at the disc tab orientation — IS tabs are horizontal, Post Mount tabs are vertical. Using the wrong adaptor will result in incorrect caliper alignment and unsafe braking performance.

Condition

Brand New: Unused and in original manufacturer's packaging.