Shortening a hydraulic brake hose on a Shimano-equipped mountain bike is one of those jobs where the small parts matter more than the tools. Every time you cut a BH90 hose, the olive and connecting insert become one-time-use hardware — the olive deforms as it seats against the hose end, and the barb-style insert grips the inner bore of the hose so it can't back out under pressure. The Shimano BH-90 Brake Hose Olive and Insert is the replacement kit for exactly that job.

This is the Y8JA98020 kit, and it's specific to the BH90 hose family. That covers BH90-SB, BH90-SS, BH90-SBLS, BH90-SBS, and BH90-SBM hoses, which is what Shimano ships on mountain brake systems including XTR M985 and M980, Saint M820, XT M785, and SLX/Deore M666. If you're working on a road or gravel setup running BH59 or BH96 hose, this is the wrong kit — those hoses use a different insert diameter and need the corresponding BH59 hardware instead.

Each kit includes one brass olive sleeve and one connecting insert-pin, enough to reterminate a single hose end. If you're shortening both the lever and caliper side, or doing front and rear brakes at the same time, plan on buying multiples up front. Nothing worse than getting the hose cut and realizing you're one olive short of finishing the bleed.... Read More