Shimano's BH-90 hose system runs through their higher-end mountain bike brakes, and the connection hardware is specific to that system. The BH-90 olive and insert set provides the two components needed to terminate a hose at the lever body. The brass olive creates the compression seal when the fitting is tightened, while the steel barb insert supports the hose wall from the inside and prevents the line from collapsing under system pressure. Using the wrong insert or olive causes connection failures that range from slow fluid weeps to catastrophic brake loss.

This fitting works with the SM-BH90-SB, SM-BH90-SS, SM-BH90-SBLS, SM-BH90-SBS, and SM-BH90-SBM hose variants. The brake compatibility list covers most of Shimano's performance mountain lineup: XTR M9000 and M9100 series, XT M8000 and M8100 series, SLX M7000 and M7100 series, Saint M820, Zee M640, and Deore M6000 through M6120. If you're running any of these brakes and need to shorten hose for a new cockpit setup, replace a damaged line, or connect factory J-kit hoses to aftermarket levers, this is the fitting you need.

The olive is a single-use component. When the compression nut tightens against the lever body, the brass deforms around the hose and into the lever housing, creating the seal. Removing the fitting destroys that seal, so plan on using a fresh olive every time you disconnect a hose at the lever. The barb insert can technically be reused if it's undamaged, but since both components cost almost nothing compared to a brake bleed or trail-side failure, replacing them as a pair during any hose work is standard shop practice.... Read More