The Yokozuna Ultimo Hy/Mech [paid link] is a hybrid mechanical-hydraulic disc brake caliper designed to offer powerful stopping force and consistent modulation. This model bridges the gap between mechanical simplicity and hydraulic efficiency, making it an appealing upgrade for cyclists looking to enhance braking without a full hydraulic conversion. In this guide, we cover everything from installation and adjustment to troubleshooting and performance tuning—ensuring you get the best out of your Ultimo Hy/Mech brakes.
Tools Required
- 5mm and 2.5mm Allen keys
- Torque wrench with Nm settings
- Cable cutters
- Needle-nose pliers
- Disc brake pad spreader
- Isopropyl alcohol and a clean cloth
- Rotor truing tool (if needed)
- Caliper alignment tool (optional but helpful)
- DOT-compatible disc brake fluid (if servicing the hydraulic portion)
Installing the Yokozuna Ultimo Hy/Mech Calipers
Frame and Rotor Compatibility
The Ultimo Hy/Mech is compatible with post mount and flat mount disc brake standards. Before beginning, ensure your frame and fork use either standard. Rotors must be 160mm or larger, depending on your intended use and fork specifications.
Mounting Procedure
Mount the caliper using the appropriate adapter and bolts provided. If mounting to a post-mount frame, be sure the adapter matches your rotor size. Lightly grease bolt threads and tighten bolts to manufacturer torque specifications—usually around 6–8 Nm.
Ensure the hydraulic piston side of the caliper faces inward. Verify caliper alignment to the rotor before final torque is applied. Use a caliper alignment tool or perform a visual centering by loosening the bolts, squeezing the brake lever, and re-tightening while holding the lever.
Cable Routing and Installation
Route your mechanical cable housing from the brake lever to the caliper. Cut the housing to length and insert ferrules at both ends. Attach the inner cable to the brake arm using the 5mm bolt and torque to 6 Nm.
Do not overtighten the cable initially. The final cable tension is best dialed in during the adjustment process.
Adjusting Brake Performance
Pad Gap and Rotor Alignment
Use a pad spreader to fully open the caliper pads. With the wheel installed and rotor in place, slowly pull the brake lever to activate the hydraulic piston. Release the lever and check for pad contact with the rotor.
If the rotor rubs, slightly loosen the caliper bolts, pull the lever, and re-center the caliper. Re-torque bolts once centered. Proper alignment ensures equal pad pressure and better modulation.
Cable Tension and Lever Feel
Adjust the barrel adjuster at the lever or inline adjuster to fine-tune cable tension. Aim for immediate engagement without excessive free stroke. Avoid overtensioning the cable, as this may prevent full piston retraction.
Pad Break-In Process
New pads require a bedding-in process. Accelerate to moderate speed (20 km/h) and apply firm braking 10–15 times. Allow the pads and rotor to cool between sets. Proper bedding increases braking power and pad longevity.
Maintenance of the Ultimo Hy/Mech
Routine Pad Inspection
Check pad thickness regularly. Replace pads before the compound wears below 1mm. Use Yokozuna-compatible organic or semi-metallic pads for best performance.
Caliper Cleaning
Clean the caliper body and rotor surface using isopropyl alcohol. Avoid contaminating pads with oils or grease. If contamination occurs, pads must be replaced.
Hydraulic System Bleeding
Although mechanical at the lever, the Ultimo’s caliper contains a sealed hydraulic circuit. Bleeding may be necessary if modulation deteriorates or lever feel becomes spongy.
To bleed:
- Remove the caliper and place it horizontally.
- Open the bleed port with a 2.5mm Allen key.
- Attach a syringe with DOT fluid and gently push fluid until no bubbles emerge.
- Close the port securely and clean any excess fluid.
Cable and Housing Replacement
If lever feel becomes inconsistent, inspect cable and housing for corrosion or compression. Replace annually or when shifting performance declines.
Troubleshooting Common Issues
Squealing Brakes
Causes include contaminated pads, glazed surfaces, or rotor misalignment. Sand the pads lightly or replace them if contaminated. Clean the rotor with isopropyl alcohol. Re-bed the pads if noise persists.
Spongy Lever Feel
This usually indicates air in the hydraulic system. Perform a bleed. Also, check for loose mechanical cable tension or kinks in the housing.
Uneven Pad Wear
Often due to caliper misalignment or piston imbalance. Realign the caliper using the squeeze-and-hold method. If issues persist, inspect for debris or piston sticking.
Rotor Rub When Not Braking
Ensure the rotor is true. Use a rotor truing tool to correct bends. Also, check that the hydraulic piston is retracting fully. If not, perform a bleed or service the caliper internals.
Customization and Performance Optimization
Lever Compatibility
The Ultimo Hy/Mech works with most road mechanical levers, including SRAM, Shimano, and Campagnolo. However, lever pull ratio may affect performance. Use levers with linear cable pull for optimal feel.
Pad Compound Selection
For increased power and heat resistance, semi-metallic or sintered pads are ideal. For quieter operation and smoother modulation, stick with organic pads.
Rotor Upgrades
Larger rotors (180mm front) provide better stopping force and heat dissipation. Ensure your fork and frame support larger sizes with the appropriate adapters.
Housing Upgrade
Switching to compressionless housing can enhance cable efficiency and brake feel. Brands like Yokozuna Reaction or Jagwire Pro Compressionless are suitable upgrades.
Compatibility with Other Drivetrain Components
The Yokozuna Ultimo Hy/Mech is agnostic to drivetrain brand but depends heavily on cable pull characteristics. It’s compatible with:
- Shimano STI levers
- SRAM DoubleTap and eTap AXS (mechanical)
- Campagnolo mechanical levers
Avoid mixing with hydraulic lever systems, as they lack the required cable actuation.
Pairing with indexed mechanical shifters is seamless, provided routing is clean and cable tension is consistent.
Comparing Ultimo Hy/Mech with Similar Models
TRP HY/RD [paid link]
The TRP HY/RD also blends mechanical actuation with a hydraulic caliper. However, the Ultimo offers a stiffer piston design and generally better lever modulation, especially under load.
TRP Spyre
Unlike the Ultimo, the Spyre is a fully mechanical dual-piston caliper. It’s easier to service but lacks the power and modulation of the Ultimo’s hydraulic assist.
Avid BB7 Road
While well-known for adjustability and reliability, the BB7 lacks the hydraulic assist of the Ultimo. It offers lower cost but reduced performance under heavy braking conditions.
Shimano GRX RX810
Though a full hydraulic system, the GRX offers superior performance but at a higher price and complexity. The Ultimo is a more accessible upgrade for mechanical users.
Frequently Asked Questions
1. Can I use Yokozuna Ultimo Hy/Mech with flat-mount frames?
Yes, with the appropriate adapters provided by Yokozuna, it fits flat-mount and post-mount setups.
2. Do I need to bleed the brakes out of the box?
No, the calipers come pre-bled. However, if performance degrades, a bleed may be necessary.
3. Are there any special levers required for Ultimo?
No, most mechanical drop-bar levers from Shimano, SRAM, and Campagnolo are compatible.
4. Can I use this with MTB levers?
No, the cable pull ratio of MTB levers is not compatible with the Ultimo Hy/Mech system.
5. How often should I replace the brake pads?
Inspect pads monthly and replace once the compound is less than 1mm or if contaminated.
6. Is it normal for the caliper to feel warm after a long descent?
Yes, mild heat is normal due to hydraulic compression. Excessive heat may indicate the need for a larger rotor or better pad compound.
Conclusion
The Yokozuna Ultimo Hy/Mech strikes a balance between simplicity and performance. With proper installation, routine maintenance, and a few performance tweaks, it can deliver braking power comparable to full hydraulic systems without the complexity. For road cyclists seeking an upgrade in control and consistency, this caliper offers a compelling solution.