Shimano Caliper Hose Locking Bolt Titanium 2.0 g vs Stock 5.0 g (3.0 g Saved per Caliper)

It clamps the hydraulic hose banjo fitting to the caliper body, sealing the brake fluid circuit. Without this bolt properly tightened, the hose can detach from the caliper under braking pressure — a catastrophic failure mode. The bolt must hold full hydraulic system pressure (typically 800-1200 psi under hard braking).

At the hose entry point on the caliper body — where the brake line connects to the caliper's internal fluid channel. On Shimano calipers, this is typically at the top of the caliper (front) or the rear-facing side (rear). The bolt threads directly into the caliper housing.

Yes. The stock bolt is identical across 105 R7170, Ultegra R8170, and Dura-Ace R9270 — all three use the same 5.0 g steel bolt with the same thread specification. TiNE's titanium replacement uses a single part number for all three tiers.

Grade 5 Ti-6Al-4V has a yield strength of roughly 880 MPa — far exceeding the clamping requirements of a brake hose fitting. The bolt does not bear braking force directly (the caliper pistons and pads handle that). It only needs to seal the hose connection under hydraulic pressure, and titanium's strength margin is well beyond what the system demands.

The caliper hose locking bolt is one of three TiNE bolts that secure Shimano's hydraulic fluid path: the STI lever hose locking bolt (5.6 g saved at the lever), the caliper hose locking bolt (3.0 g saved at each caliper), and the caliper bleed port bolt (2.8 g saved at each caliper). Together, these three bolt types save 11.4 g across the complete hydraulic line per bike (front + rear).