The Yokozuna Ultimo Hy/Mech [paid link] is a hybrid mechanical-hydraulic disc brake system known for its powerful braking performance, wide compatibility, and consistent modulation. Unlike traditional mechanical calipers, it combines the cable-actuated simplicity of mechanical brakes with the power and feel of hydraulic braking. Replacing brake pads on the Ultimo Hy/Mech requires precision and proper technique to maintain braking efficiency and avoid rotor contamination or pad misalignment. This guide walks you through every step of the replacement process.
Tools Required
- 5mm Allen key
- Flat-blade screwdriver or pad spreader tool
- Needle-nose pliers
- New brake pads compatible with Yokozuna Ultimo Hy/Mech (organic or sintered)
- Isopropyl alcohol (minimum 90%) and lint-free cloth
- Torque wrench (Nm scale)
Accessing the Brake Pads
The first step in replacing pads involves removing the wheel and gaining direct access to the caliper interior.
The Ultimo Hy/Mech caliper uses a top-loading pad design, which simplifies pad replacement without fully removing the caliper from the frame or fork. Begin by shifting your gears to avoid chain tension near the dropout (rear) or moving the front caliper inward.
Remove the wheel carefully to avoid damaging the rotor or contaminating the pads. Keep the rotor clean and avoid touching the braking surface.
Removing the Old Pads
To remove the pads, begin by releasing the pad retention mechanism. On the Ultimo Hy/Mech, this is a central pad retention bolt that also serves as the clip anchor.
Using a 5mm Allen key, unscrew and remove the pad bolt from the caliper body. Carefully withdraw the old pads and their spring clip using needle-nose pliers. If the pads seem stuck, use a flat-blade screwdriver to gently push them upward from below, taking care not to damage the caliper.
Inspect the pad surfaces for uneven wear, glazing, or contamination. This can reveal issues with piston retraction or rotor alignment.
Cleaning the Caliper Interior
Before installing new pads, it’s essential to clean the piston surfaces and caliper cavity. Use isopropyl alcohol and a lint-free cloth to clean inside the caliper, ensuring no old pad material or grime remains.
Lightly press the pistons back into the caliper body using a plastic tire lever or pad spreader tool. Do not use a metal object, as it may damage the ceramic or composite piston surfaces.
Make sure the pistons move smoothly and evenly. Sticky pistons may require a full service or lubrication using a mineral oil-compatible seal conditioner.
Installing New Pads
Insert the new pads into the caliper with the spring clip properly centered between them. The friction surface must face inward toward the rotor. The pads will slide down into the top-loading slot and should seat snugly against the pistons.
Reinstall the pad retention bolt through the center of the caliper and torque it to the manufacturer’s specification (typically 5–6 Nm). Confirm that the pads sit evenly on both sides and do not rock or shift in place.
Reinstalling the Wheel and Aligning the Caliper
Once the new pads are in place, reinstall the wheel and secure the axle. Spin the wheel to check for rotor rub.
If rubbing occurs, you may need to adjust caliper alignment. Loosen the caliper mounting bolts slightly and squeeze the brake lever firmly to center the caliper over the rotor. While holding the lever, tighten the bolts to 6–8 Nm.
Visually inspect the caliper to ensure even pad spacing on each side of the rotor. Minor rubbing may go away after a short break-in ride.
Bed-In Procedure
New brake pads must be properly bedded in to ensure optimal performance. This process helps transfer pad material to the rotor and improves initial bite.
Find a safe, traffic-free location and perform 15–20 moderate to strong stops from around 20–25 km/h to walking speed. Allow the system to cool slightly between stops. Avoid coming to a complete stop with the brakes fully applied, as this can cause uneven pad transfer.
After bedding in, your Ultimo Hy/Mech should deliver smooth and powerful braking with consistent lever feel.
Troubleshooting Common Issues
Rotor Rub After Installation:
Rotor rub is often caused by piston misalignment or caliper offset. Re-centering the caliper as described above usually resolves the issue. If rubbing persists, inspect for warped rotors or uneven piston extension.
Noise When Braking:
Squealing noises may result from contamination or improper bedding. Remove the pads, clean both rotor and pad surfaces with isopropyl alcohol, and re-bed the system. If noise continues, consider switching to a different pad compound.
Lever Feel is Spongy or Inconsistent:
While Ultimo Hy/Mech is cable-actuated, it has a closed hydraulic system. Air ingress or heat expansion can affect feel. Bleeding is not user-serviceable, so consult a professional if symptoms persist after pad replacement.
Customization and Optimization
The Ultimo Hy/Mech supports customization in pad material and lever-cable actuation pairing. Riders seeking quieter operation can use organic pads, while those riding in wet or mountainous regions may prefer sintered pads for durability.
Adjusting the cable tension using the barrel adjuster can fine-tune bite point feel. However, do not overtighten the cable, as this can prevent the hydraulic piston from returning fully, leading to rotor drag.
Compatibility with Other Drivetrain Components
The Ultimo Hy/Mech is designed for compatibility with standard road brake levers that use traditional cable pull, including Shimano STI, SRAM DoubleTap, and Campagnolo Ergopower. Ensure the housing and cable are in good condition, as excess friction can impact lever feel.
It pairs well with both Shimano and SRAM road drivetrains and rotors. Rotor size should be matched to the rider’s weight and terrain for optimal performance (140mm for road use, 160mm for mixed terrain or heavier riders).
Comparing to Similar Models
Compared to full hydraulic calipers, the Ultimo Hy/Mech offers easier setup without the need for bleeding, making it a favorite among mechanical drivetrain users. Versus other hybrid systems like TRP HY/RD [paid link] or Juin Tech GT-F, the Ultimo delivers superior modulation and a more robust construction, though it may feel slightly bulkier.
Its pad retention and piston design give it an edge in reliability, particularly for gravel and endurance riders who prioritize field serviceability.
Conclusion
Replacing the brake pads on the Yokozuna Ultimo Hy/Mech is a straightforward yet precision-dependent process that requires careful alignment and attention to detail. When done correctly, it restores braking power and ensures safe, responsive stopping performance. With proper care, the Ultimo system will continue to deliver consistent braking across varied conditions, making it a dependable choice for both road and gravel cyclists.