Shimano STI Lever Hose Locking Bolt Titanium 4.0 g vs Stock 9.6 g (5.6 g Saved)

The hose locking bolt on Shimano STI levers clamps the hydraulic brake line to the lever body. Across 105 R7170, Ultegra R8170, and Dura-Ace R9270, the stock steel bolt weighs 9.6 g per set. TiNE's Grade 5 Ti-6Al-4V replacement drops that to 4.0 g, saving 5.6 g on a bolt most riders never inspect — and one that sits high on the handlebar, where rotational mass matters most.

Weight Comparison by Shimano Tier

The stock hose locking bolt is identical across all three Shimano hydraulic groupsets — same steel bolt, same 9.6 g. TiNE's titanium replacement fits all three tiers with a single part number:

Where the Bolt Lives — STI Lever Body

The hose locking bolt is located at the top of the Shimano STI lever body, where the hydraulic hose exits the lever and routes toward the caliper. It secures the hose banjo fitting to the lever's hydraulic circuit, preventing fluid leaks under braking pressure. Because this bolt sits on the handlebar — the highest point of the bike — every gram saved here reduces the moment of inertia that the rider must overcome when lifting the bar over obstacles or during rapid steering inputs.

Why high-position weight matters. Mass at the handlebar level has a disproportionately large effect on handling feel compared to mass at the saddle or bottom bracket. The lever body is one of the highest points on the bike. Swapping a 9.6 g steel bolt for a 4.0 g titanium one at this position reduces rotational inertia at the bar — the rider feels the difference in steering responsiveness more than the same weight savings at the bottom bracket.

Stacking Savings Across the Hydraulic System

The STI lever hose locking bolt is one of several TiNE titanium replacements in Shimano's hydraulic disc brake system. When combined, the savings compound through every fluid line connection:

Grade 5 Ti-6Al-4V, CNC machined, 8 anodized colors (gold, blue, rainbow, silver, black, pink, green, multi). The titanium bolt maintains full clamping force on the banjo fitting — no hydraulic leak risk, no compromise on brake line security. One part number covers all three Shimano hydraulic groupsets.