ONYX 80V MOKE Front Brake Caliper

Many ONYX 80V riders eventually look at increasing front braking performance, especially when riding aggressively, riding hills, or carrying extra load. The MOKE large front caliper upgrade increases thermal capacity, pad surface area, and clamp force while remaining compatible with the stock hydraulic system.

This guide covers real-world installation, safe torque ranges, bleeding procedure, thermal behavior, braking physics, and how regenerative braking works together with friction braking.

Why Upgrade the Front Brake Caliper

The stock 80V front and rear brake calipers are well matched and perfectly safe for normal riding. However, on nearly all two and four wheel vehicles, the front brake performs the majority of the stopping work due to weight transfer during deceleration.

Under braking, weight shifts forward. This increases front tire traction and reduces rear tire traction. Because of this, increasing front braking capacity can improve:

• Peak stopping force
• Fade resistance under repeated braking
• Thermal capacity during hill riding
• Stability during aggressive braking

If you ride hard, carry extra load, or ride in steep terrain, a larger front caliper is a meaningful upgrade.

Purchase MOKE Brake Kit

To purchase the MOKE larger aftermarket front brake caliper kit for the 80V, contact Henry Strange directly.

• Contact Henry

Other Parts

• Brake Fluid DOT 3 & 4
• Brake Bleed Kit & Hose

Compatibility Notes

The MOKE large front caliper upgrade works with:

• Stock brake master cylinder
• Stock brake lever
• Stock brake reservoir

No hydraulic ratio changes are required.

Use only:

• DOT 3 brake fluid
• DOT 4 brake fluid

Do NOT mix DOT 5 silicone fluid.

Safety and Work Environment

Brake fluid is highly corrosive to paint and finishes.

Perform this job:

• Outdoors
• In a garage work space
• Away from finished flooring

Always place towels under:

• Front caliper
• Front brake master cylinder

Tools and Supplies

Required tools:

• Brake bleed kit
• Brake cleaner
• Shop towels
• 10 mm socket
• 12 mm socket
• 8 mm wrench
• 1/2 inch wrench
• Fluid catch container
• Nitrile gloves recommended

Pre Assembly of the New Caliper

Before removing the stock caliper, pre assemble the new caliper and mounting bracket.

Install:

• Bracket to caliper body
• Supplied spacers
• Mounting bolts through bracket
• Self locking nuts

Snug only. Final torque happens after mounting to fork.

This step reduces install time while fluid is exposed.

Stock Caliper Removal

Remove master cylinder reservoir cap first to release pressure.

Then:

1. Loosen brake hose at stock caliper
2. Remove TWO bracket to fork bolts
3. Remove caliper assembly

Important:

• Remove only the bolts attaching the bracket to the fork mount
• Do NOT remove caliper body bolts
• Do NOT remove pad retaining hardware

Brake fluid will begin dripping once hose is disconnected. This is normal.

Keep hose elevated when possible.

Installing the New MOKE Caliper

Attach brake hose to new caliper FIRST.

Verify:

• Copper crush washers seated correctly
• Hose routing matches natural bend
• No twist in line

Then mount caliper assembly to fork using supplied hardware.

Tighten evenly.

Brake Pad Differences (Stock vs MOKE)

The MOKE pads are physically larger than stock pads.

Benefits include:

• Larger friction surface area
• Higher heat absorption capacity
• More consistent braking under load
• Reduced fade during repeated braking

Torque Specifications

Torque specs are provided, use these safe ONYX-grade ranges.

Caliper Bracket to Fork Bolts

Typical Range: 25–35 Nm (18–26 ft lb)

Caliper Mount Hardware (Bracket to Caliper)

Typical Range: 20–25 Nm (15–18 ft lb)

Brake Hose Banjo Bolt

Typical Range: 18–25 Nm (13–18 ft lb)

Never overtighten banjo bolts. Crushing washers seal by compression, not brute force.

Brake Bleeding Procedure

Fill reservoir with fresh fluid.

MOKE brake bleed tip: Mount the caliper bracket loosely to the fork mount. Remove yellow stopper where the banjo bolt attaches the hose. Prefill caliper with brake fluid.

Cycle process:

• Pump lever slowly
• Hold lever
• Crack bleed valve
• Close valve
• Release lever
• Repeat

50+ lever cycles maybe required.

Goal is:

• Remove all air
• Replace with clean fluid
• Achieve firm lever feel

Never let reservoir run dry during bleeding.

Common Mistakes Riders Make

• Removing caliper body bolts instead of bracket bolts
• Twisting the brake hose before tightening mount hardware
• Letting reservoir run dry during bleeding
• Over tightening banjo bolt
• Installing pads with contamination
• Not checking rotor free spin before bleeding
• Skipping final leak check

Technical Deep Dive

During braking, longitudinal weight transfer increases normal force on the front tire. Braking force potential is proportional to tire traction coefficient multiplied by normal force.

As front load increases:

• Front tire can generate more braking force
• Rear tire becomes easier to lock

Increasing front caliper piston area increases hydraulic clamp force for a given lever pressure. Larger pads increase thermal mass, heat dissipation surface, and friction stability, improving performance under repeated heavy braking cycles.

Hydraulic Ratio and Piston Area Explained

Hydraulic Pressure = Lever Force ÷ Master Cylinder Piston Area Clamp Force at Caliper = Hydraulic Pressure × Caliper Piston Area

Diagram Style Concept

Brake Lever Force ↓ Master Cylinder Piston ↓ Brake Fluid Pressure ↓ Caliper Pistons ↓ Brake Pad Clamp Force ↓ Rotor Friction → Bike Slows Down

Example Comparison

Brake Fluid Boiling Point vs Brake Fade

Brake Pad Compound vs Rotor Wear

Heat Soak vs Downhill Braking

Heat soak occurs when heat input exceeds cooling rate.

Energy conversion during braking:

Energy → Rotor Heat Energy → Pad Heat Energy → Caliper Heat Energy → Brake Fluid Heat

Why Front Brakes Do ~70–90% of the Stopping

ΔW = (m × a × h) ÷ L

Example:

m = 150 kg h = 0.55 m L = 1.30 m a = 6.87 m/s²

ΔW ≈ 435 N ≈ 44 kg load transfer

Rotor Temperature vs Braking Force

• Low Temperature → Good bite
• Moderate Temperature → Strongest friction stability
• High Temperature → Friction plateau or drop
• Extreme Temperature → Pad fade or fluid fade

How ~15% Regenerative Braking Works With This Setup

• Regen reduces friction brake workload.
• Friction braking → Heat at rotor and pads
• Regen → Energy returned to battery

Motor heat from regen mainly comes from:

• I²R winding losses
• Controller switching losses
• Battery charging losses

These are small compared to friction heat.

Regen Braking Motor Heat

Regenerative braking adds very little heat to the motor in real-world riding. In testing across a wide range of riding conditions, including cruising around 25 mph, high speed runs around 70 mph, and steady downhill riding around 35 mph, motor temperature only increased by about 4 °C (7.2 °F). In practical terms, that is an extremely small thermal change and is nowhere near the level that would stress or harm a motor.

• 25 mph cruising → negligible temp change.
• 70 mph high speed riding → still minimal regen heat contribution.
• 35 mph downhill steady regen → small gradual temp increase only.
• 4 °C (7.2 °F) total observed increase → very low thermal load overall.

Final Safety Check

• Confirm no fluid leaks
• Confirm firm lever feel
• Confirm rotor spins freely
• Confirm all hardware torque

Perform slow speed brake test before normal riding.

Final Thoughts

If you are happy with the stock braking system, there is nothing wrong with staying stock.

If you ride aggressively, ride hills, or carry load, the larger front caliper is a meaningful upgrade in braking confidence and thermal stability.