The Ultegra/Dura-Ace compatible non-series BR-RS811-R rear caliper is a rim brake model designed for two bolt direct mount set-up on the chainstays for under the "under the bottom bracket" direct mount rim brake designed framesets. User will need an inline cable adjuster (SM-CB90 or comparable) for cable adjusting and release feature to work properly.

The BR-RS811-R Direct Mount Brake Calipers offer 28mm tire clearance, work with external rim widths from 20.8-28mm, and have the standard 51mm reach. The same angle and pivot adjustable magnesium pad holder and R55C4 standard Shimano brake pads offer a perfect set-up every time. Shimano has maintained the same cable pull ratio as the R9100, 9000, R8000, 6800, 5800 series levers, so you can upgrade or replace your caliper as desired or required.

In order to improve overall power and aerodynamics, the aluminum caliper has been reshaped, with augmentation to provide greater stiffness and more consistent braking under heavy power. This may be noticeable more to heavier riders, or those who tend to brake as late as is feasible. It will take a truly sensitive rider to feel improvement in feel, but most will notice subtleties when paired with R9200/R8100 series levers, as the ergonomics and leverage in the STI do feel different, despite the carry over of the cable pull ratio.

Direct mount designs may offer the two fixed mounting points that eliminate a major engineering challenge of dual pivot brakes, but even more precision must be achieved to ensure proper brake pad alignment and closure to the rim. Even a slight error can result in poor braking and uneven rim pressure. Shimano has created a super smooth, linear feel with their SLR-EV standard and with added power and a cleaner profile, so the BR-RS811 Direct Mount Brake Caliper will not only impress, but exceed rider expectations. Shimano offers the standard seatstay frame (BR-R9210-RS), and fork (BR-R9210-F) direct mount versions, as well as this special rear brake for under-chainstay, behind the bottom bracket design (BR-RS811-R) that is used on some rim brake aero road, time trial, and triathlon framesets. Return to Top