Shimano Caliper Oil Port Bolt 1.8 g vs Stock 4.6 g (2.8 g Saved)

The Shimano caliper oil port bolt set — the bolts that seal the bleed ports on Shimano disc brake calipers — weighs 4.6 g in stock form across all three Di2 groupsets (R7170, R8170, R9270). TiNE's titanium replacement set weighs 1.8 g, saving 2.8 g per caliper pair.

2.8 g per caliper set — 5.6 g for both front and rear calipers. The oil port bolts sit directly on the brake caliper body, one of the most corrosive environments on the bike — brake dust, road spray, and wet-weather grime all accumulate here. Two calipers mean two bolt sets, so the total savings across front and rear is roughly 5.6 g. Grade 5 Ti-6Al-4V provides far better corrosion resistance than the stock steel bolts in this harsh environment.

What the Oil Port Bolt Set Replaces

Shimano disc brake calipers have two bleed ports — one for the hose connection and one for the oil reservoir — each sealed by a small bolt. These bolts are removed during brake bleeding (oil change) and re-installed afterward. The stock bolts are steel, weighing 4.6 g for the complete set per caliper.

TiNE's titanium set at 1.8 g replaces both bolts in one purchase. The bolts are CNC-machined from Grade 5 Ti-6Al-4V with precise threading that matches the caliper bleed port interface. Same threading, same sealing function, same installation process — direct swap.

All Three Di2 Groupsets — Same Stock Weight

Unlike other Shimano bolts where the stock weight varies across groupsets (the R7170 pivot bolt at 8.4 g versus R9270 at 3 g), the caliper oil port bolts are identical across all three Di2 groupsets at 4.6 g per set. This means the TiNE set saves 2.8 g regardless of whether you ride 105, Ultegra, or Dura-Ace — no groupset-specific version needed.

Why Titanium Matters in the Brake Zone

The caliper body is the most corrosive zone on a road bike — brake dust containing metal particles, road spray carrying salt and grit, and wet-weather grime all accumulate directly on the caliper surface. Stock steel oil port bolts develop surface rust and thread degradation over time, especially on bikes ridden in rain or stored outdoors.

Grade 5 Ti-6Al-4V resists corrosion far better than steel in this environment. For riders who perform regular brake bleeding (recommended every 6~12 months for Shimano hydraulic systems), the titanium oil port bolts provide a smooth threading experience every time — no thread binding, no corrosion-induced resistance, no risk of cross-threading a rusted bolt into the caliper body.

This is a practical advantage that matters more than the 2.8 g weight savings. A corroded steel oil port bolt that binds in the caliper thread can make brake bleeding difficult or damage the caliper's sealing interface. TiNE's titanium version eliminates that risk entirely.