The Shimano Ultegra ST‑R8160 TT is a high-performance dual-control lever designed specifically for time trial and triathlon applications, combining hydraulic disc braking with Di2 electronic shifting. For optimal braking efficiency, it’s crucial to maintain a clean and air-free hydraulic system. Over time, brake fluid can degrade or accumulate air bubbles, affecting lever feel and stopping power. This guide provides detailed instructions on how to bleed the Ultegra ST‑R8160 TT brake sets at home, ensuring consistent performance and reliability.
Tools Required
- 4mm and 5mm Allen wrenches [paid link]
- Shimano Bleed Kit (TL-BT03-S or TL-BT03-R)
- Shimano Mineral Oil [paid link] Brake Fluid
- Bleed funnel and stopper
- 7mm open-ended wrench
- Clean rags or shop towels
- Isopropyl alcohol (90% or higher)
- Plastic catch bottle with hose
- Zip ties or rubber bands (optional for bottle positioning)
- Nitrile gloves
- Torque wrench (Nm-specific)
Preparing for the Bleed Procedure
Before starting, ensure the bike is in a workstand with the front wheel removed if you’re working on the front brake. Place the handlebars in a stable, level position to keep the brake lever parallel to the ground. Remove the brake pads and insert a bleed block to prevent contamination and piston overextension.
Inspect the hydraulic hoses and caliper area for any visible damage or leakage. If any component appears compromised, replace it before bleeding. Clean the lever body and caliper using isopropyl alcohol to eliminate any residual grime or old fluid.
Lever Preparation: Ultegra ST‑R8160 TT Specifics
Unlike standard STI levers, the ST‑R8160 TT integrates Di2 shifting and requires careful handling to avoid damaging the electronics during bleeding. Begin by removing the bleed port screw from the top of the lever body using a 2.5mm Allen wrench.
Attach the Shimano bleed funnel filled with a small amount of mineral oil to the port. Ensure the funnel stopper is in place to prevent fluid from leaking before you begin pushing fluid through the system.
Caliper Setup and Fluid Push
With the funnel secured, move to the brake caliper. Locate the bleed nipple on the caliper and attach a clear hose to it, routing the other end into a catch bottle. Use a 7mm wrench to control the bleed port.
Open the bleed nipple slightly and slowly squeeze the brake lever several times to push air bubbles and old fluid through the system. Ensure the funnel is topped up as needed to prevent air from entering. Continue this process until the fluid coming out of the caliper runs clean and bubble-free.
Closing the System and Fluid Top-Up
Once the system is purged of air and old fluid, close the bleed nipple while maintaining pressure on the lever. Remove the funnel stopper and top off the fluid if needed. Carefully remove the funnel and reinstall the bleed screw on the lever.
Wipe any spilled fluid immediately with isopropyl alcohol. Reinstall the brake pads and wheels, then check for rotor rub. Re-align the caliper if necessary and torque all bolts to manufacturer specifications.
Lever Feel and Test Ride
Pull the brake lever several times to confirm a firm, consistent lever feel. If the lever feels spongy, repeat the bleeding process, ensuring no air remains in the system. Take the bike for a short test ride to verify braking performance under load.
Pay close attention to lever return speed and modulation. The Ultegra ST‑R8160 TT should deliver smooth, predictable braking with minimal free stroke.
Troubleshooting Common Issues
Spongy Lever After Bleed
Air may still be trapped in the system, especially in the caliper or hose junction. Repeat the bleed process, this time gently tapping the hose to dislodge air bubbles.
Fluid Overflow at Funnel
This typically indicates overfilling. Drain a small amount of fluid using the stopper and adjust the funnel level.
Brake Pads Contaminated
If mineral oil contacted the pads, they must be replaced. Contaminated pads cannot be effectively cleaned and will lead to poor braking.
Leaking Caliper or Lever
Check all bolt torques and seals. If leaks persist, inspect internal seals and consider replacement if necessary.
Performance Optimization Tips
For time trialists and triathletes, lever feedback is crucial. Ensure all connections are torqued to spec and that hoses are routed cleanly to avoid unnecessary friction or bending. Use Shimano mineral oil exclusively, as alternatives can degrade seals and compromise performance.
Bleed your system every 6–12 months, especially if you race in varied conditions or use your bike frequently in wet environments. This maintains consistent braking and prevents fluid degradation.
Customization and Rider-Specific Setup
The ST‑R8160 TT levers allow for some adjustment in lever throw and free stroke. Use these adjustments to tailor lever feel to your hand size and braking preference. Riders with smaller hands may prefer shorter throw, while others may favor a longer modulation range for better control.
If you’ve recently upgraded from mechanical disc or rim brakes, take time to adapt to the hydraulic system’s power and sensitivity. The feedback can be significantly different, especially at high speeds.
Compatibility Considerations
The Ultegra ST‑R8160 TT levers are designed to work seamlessly with Shimano’s flat-mount hydraulic disc calipers and 12-speed Di2 electronic shifting systems. Ensure compatibility with:
- Shimano BR-R8170 or BR-R9270 calipers
- Shimano RT-MT900 or RT-CL800 rotors
- Shimano SM-BH90 hydraulic hoses
Mixing components from different series or manufacturers may result in suboptimal braking or complete system incompatibility.
Comparison with Similar Models
Compared to the Shimano Dura-Ace ST-R9270 TT levers, the Ultegra ST‑R8160 TT offers nearly identical braking performance at a slightly heavier weight and lower price point. While the Dura-Ace option includes slightly improved ergonomics and weight savings, the Ultegra model remains a top-tier choice for competitive time trialists prioritizing value and reliability.
In contrast, mechanical TT brake levers paired with cable-actuated discs or rim brakes offer less braking power and require more frequent maintenance. The ST‑R8160 TT’s hydraulic integration marks a significant upgrade in modulation and stopping force.
FAQs
1. How often should I bleed the Ultegra ST‑R8160 TT brakes?
Every 6 to 12 months, or immediately if you notice spongy lever feel or reduced braking power.
2. Can I use DOT fluid instead of Shimano mineral oil?
No. Only Shimano mineral oil is compatible with ST‑R8160 TT systems. Using DOT fluid will damage seals and void warranties.
3. What should I do if air bubbles keep appearing during the bleed?
Repeat the bleed slowly and ensure all hose fittings are tight. Tap the hoses lightly during the bleed to dislodge stubborn air bubbles.
4. Are these levers compatible with non-Shimano calipers?
Not recommended. For best performance and safety, use them with Shimano flat-mount hydraulic calipers only.
5. Is it necessary to remove the caliper from the frame during bleeding?
Not usually. However, rotating or repositioning the caliper slightly can help move trapped air during bleeding.
6. How do I know when the fluid is fully bled?
The lever should feel firm and consistent with no sponginess. Fluid in the catch bottle should be clean and free of bubbles.
Conclusion
Bleeding your Shimano Ultegra ST‑R8160 TT brake set at home ensures continued top-tier braking performance and safety. With the right tools and careful attention to each step, even home mechanics can achieve professional-quality results. Regular maintenance not only extends component life but also preserves confidence during high-speed, high-stakes time trials.