The Shimano Ultegra ST‑R8160 TT brake set offers streamlined aerodynamics and dependable hydraulic performance, making it an increasingly popular choice for gravel and time trial builds. While designed with triathlon and time trial bikes in mind, gravel cyclists can also benefit from the compact shifter profile and crisp hydraulic modulation this unit provides. This guide walks through a detailed, step-by-step approach to installing, adjusting, and maintaining the ST‑R8160 TT brake system on a gravel bike.
Tools Required
- 5mm Allen wrench
- 2.5mm Allen wrench
- Shimano mineral oil [paid link]
- Shimano TL-BH62 or TL-BH61 tool (for hydraulic line cutting)
- Shimano bleed kit (TL-BT03-S or similar)
- Torque wrench (2–10 Nm range)
- Hydraulic hose clamps
- Cable cutters
- Clean rags and isopropyl alcohol
Component Overview
The Ultegra ST‑R8160 TT integrates dual control lever functionality with Di2 electronic shifting and hydraulic braking. Its compact, ergonomic lever body is optimized for bar-end installations, offering precise actuation in both shifting and braking. Designed to work with Shimano’s 12-speed Di2 systems and hydraulic disc brakes, it supports advanced performance in harsh off-road conditions.
Preparation and Compatibility
Before starting, confirm compatibility with your existing drivetrain. The ST‑R8160 TT is only compatible with Shimano 12-speed Di2 electronic drivetrains and must be paired with Shimano hydraulic disc calipers, ideally BR-R8170 for consistent modulation. Your gravel bike should also have internal or semi-internal cable routing to cleanly integrate the Di2 wires and hydraulic hoses.
If retrofitting the levers into a non-time trial bar with bullhorn-style extensions, ensure there is enough internal space to house both the Di2 wire connections and hydraulic line.
Installation Process
Lever Mounting
Begin by preparing the handlebar extensions. Use a 5mm Allen wrench to remove the end caps and align the lever body within the extension openings. Insert the levers and secure them to the bars, tightening to a torque of 6–8 Nm. Ensure lever symmetry on both sides for ergonomic balance.
Shimano’s levers come with an integrated junction box (EW-RS910 or similar). Install Di2 wires into the ports, routing them internally toward the main junction (typically located inside the downtube or bottom bracket area).
Hydraulic Hose Routing and Connection
Cut your hydraulic hoses to length using a TL-BH62 tool. The hose length should allow full handlebar rotation without kinking. Use Shimano’s connecting insert and olive, and attach the hose to the lever using a 2.5mm Allen wrench. Torque the connection bolt to 5–6 Nm.
Route the hose internally through the bar and frame to the caliper. Use hydraulic-specific clamps to secure any external segments.
Brake Bleeding
Bleeding is critical to performance and must be done after installation. Attach the Shimano funnel to the lever bleed port and fill it with Shimano mineral oil. Open the caliper bleed valve and cycle the lever slowly to purge air bubbles.
Close the caliper port while fluid still fills the funnel, then remove the funnel and cap the lever port. Wipe down the area with isopropyl alcohol to remove excess oil.
Repeat the process for the second lever and brake caliper. Verify that both systems exhibit firm lever feel before riding.
Adjustment for Gravel Terrain
The ST‑R8160 lever reach can be adjusted with a small Allen bolt beneath the lever body. Shorten the reach for aggressive, off-road positioning or increase it for stability during descents. Brake pad clearance can be tuned at the caliper level using Shimano’s inboard and outboard adjustment screws.
Brake bite point is automatically set, but Di2 firmware updates and micro-adjustments can be made through the E-Tube Project app for optimal shifting/braking response in gravel conditions.
Maintenance Recommendations
Regular inspection is crucial for maintaining brake consistency in gravel environments. After every 500 km of off-road riding:
- Check lever pivot points for dirt and debris buildup.
- Inspect hydraulic hose junctions for leaks.
- Clean and lubricate lever return springs if resistance increases.
- Replace brake fluid every 6 months, especially after riding in wet or muddy conditions.
Keep Di2 wire connections tight and free from moisture, particularly in humid or sandy regions.
Troubleshooting Common Issues
Spongy Brake Feel
Air trapped in the system usually causes this. Re-bleed the brake using Shimano’s procedure, ensuring both ends of the line are free of air bubbles.
Lever Not Returning Smoothly
This can indicate spring fatigue or contamination inside the lever body. Disassemble the lever pivot and clean thoroughly. Lightly lubricate with silicone-based grease.
Intermittent Shifting Response
Check the Di2 wire connections at the ST‑R8160 lever and junction box. Corrosion or partial disconnection is often the cause. Replace corroded wires if needed.
Customization and Optimization
For gravel riders who prefer a unique bar configuration, pairing the ST‑R8160 with bullhorn extensions and a central top tube-mounted Junction A box allows streamlined electronics access. You can also reprogram shift functions using Shimano’s E-Tube software, assigning specific up/downshift commands to either lever for intuitive operation on rugged terrain.
Additionally, pairing the ST‑R8160 with Shimano’s servo wave calipers enhances modulation—ideal for gravel descents requiring subtle braking input.
Model Comparison: ST‑R8160 vs. ST‑R9180
Compared to the Dura-Ace ST‑R9180, the Ultegra ST‑R8160 offers nearly identical performance at a more accessible price point. Weight differences are minimal, and the core functionality—hydraulic braking and Di2 shifting—remains consistent. The R9180’s materials are slightly lighter and feature higher-grade finishes, but for gravel applications where durability trumps marginal weight savings, the ST‑R8160 remains the more pragmatic choice.
Compatibility Overview
The ST‑R8160 TT is fully compatible with:
- Shimano 12-speed Di2 derailleurs
- BR-R8170 hydraulic disc calipers
- EW-SD300 Di2 wires and EW-JC304 junctions
- Shimano RT-CL800 and RT-MT800 rotors
It is not compatible with 11-speed systems, mechanical derailleurs, or SRAM/Avid hydraulic systems.
Frequently Asked Questions
1. Can I use ST‑R8160 levers with mechanical derailleurs?
No. The ST‑R8160 levers are designed exclusively for Shimano’s 12-speed Di2 systems.
2. How often should I bleed the hydraulic lines?
Every 6 months or after any major ride in wet or muddy conditions.
3. Can I use these levers on a standard drop bar?
Not ideally. They are shaped for bar-end installation in aero [paid link] or bullhorn extensions.
4. Is the ST‑R8160 compatible with 11-speed drivetrains?
No. It is built exclusively for 12-speed Shimano Di2 systems.
5. Can I use SRAM rotors with Shimano calipers?
Technically yes, but performance and heat management are optimized with Shimano rotors.
6. What’s the main difference between ST‑R8160 and ST‑R9180?
Materials and minor weight differences. Performance is nearly identical for most riders.
Conclusion
The Shimano Ultegra ST‑R8160 TT brake set is a high-performance, reliable, and aerodynamic component well-suited for gravel riders seeking precision braking and Di2 shifting integration. With proper installation, maintenance, and customization, it can transform the handling and control of your gravel bike, delivering confidence and control in every condition.