SHIMANO BR-RS811｜Under-BB Mount Brake That Fits Beautifully into Aero Frames

Aesthetics that integrate with the frame, and reliable braking power.

The SHIMANO BR-RS811 is a direct-mount rear brake caliper designed for under-BB (bottom bracket) mounting.

Specifically designed for under-BB mounting, often found on aero road bikes and time trial bikes, it features a low-profile design that enhances integration with the frame. It achieves both aerodynamic performance and style while providing stable braking power.

Compatible with SHIMANO's SLR-EV technology, it offers light lever operation and high control. With an excellent balance of rigidity, weight, and braking power, it supports high performance in a wide range of situations, from racing to long rides.

It supports tires up to 28C, accommodating the wide tires that have become popular in recent years. This direct-mount brake brings out the performance of modern road bikes.

Features

• Direct mount brake caliper exclusively for under-BB mounting
• Low-profile design for improved aerodynamic performance
• Design with an excellent balance of rigidity, lightness, and braking power
• Light lever operation and high control performance thanks to SLR-EV compatibility
• Supports tires up to 28C
• Uses cartridge-type brake shoes
• Shoe angle adjustment function
• Suitable for a wide range of uses, from road racing to long rides

SPEC

• Brand: SHIMANO
• Model: BR-RS811
• Type: Direct Mount Brake Caliper (Under-BB Mount)
• Compatible Standard: SLR-EV
• Reach: 51mm
• Brake Shoe: Normal type
• Maximum Compatible Tire Size: 28C
• Compatible Rim Width: 20.8-28mm
• Functions: Cartridge shoe holder, tire guide bumper, quick release lever, shoe angle adjustment
• Notes: SM-CB90 inline cable adjuster is required for cable adjustment and quick release functions

While under-BB mounting is often adopted for aero road and TT bikes, the BR-RS811 offers surprisingly strong braking power.

It maintains the frame's silhouette and provides a clean look from the side, a characteristic unique to direct mount brakes. With the easy-to-use brake feel characteristic of SLR-EV, speed adjustment feels smooth and controlled.

Since it supports the increasingly popular 28C tires, it is also recommended for customizing road bikes that prioritize comfort. This model is perfect for those who want to achieve both aerodynamic performance and braking performance.