How to Maintain Your Bonnell 775 MX for Peak Performance

The Bonnell 775 MX isn’t your everyday electric mountain bike — it’s a high-performance, torque-heavy machine built to dominate brutal off-road terrain. But just like any elite piece of equipment, it only performs at its best when you take care of it properly.

Whether you’re riding it hard on dirt trails or cruising downhill jumps, maintenance isn’t optional — it’s the difference between crushing rides and costly breakdowns.

Let’s break down how to keep your Bonnell 775 MX in beast mode, all year round.

1. Battery Maintenance:

The 65V 1,300Wh battery is the lifeblood of the 775 MX. Here’s how to make it go the distance:

• Charge after every ride, even short ones — lithium-ion cells love consistency.
• Avoid 100% full or 0% empty. Keep it between 20–90% for everyday use to preserve cell health.
• Never charge a hot battery. Let it cool after a heavy ride before plugging in.
• Store at ~50% if leaving unused for more than a week.
• Use the original charger only — aftermarket chargers can damage the BMS (Battery Management System).

2. Motor & Keep It Tight, Keep It Clean

The Bonnell’s high-torque motor and aggressive gearing are designed for serious climbing and instant acceleration — but they demand respect.

• Chain: Clean and lube after every dusty or muddy ride. Use e-bike specific chain lube — regular lube wears out faster under torque.
• Cassette & Derailleur: Wipe down grime and check alignment regularly. A misaligned derailleur can cause chain slips, especially under throttle.
• Motor Mounts: Inspect monthly. The torque of a 6,000W peak motor can loosen hardware over time.
• Noise Check: Unusual sounds (grinding, clicking) from the motor area could mean worn bearings or improper chain tension — fix fast.

3. Suspension Setup:

Your 775 MX comes loaded with Suntour RUX 38 RC+ front forks (200mm) and a TriAir 3CR rear shock (170mm). They’re tuned for hard-hitting terrain — but only if maintained properly.

• Air Pressure: Check fork and shock pressure monthly (or after big ride changes). Incorrect pressure ruins ride feel.
• Sag Adjustment: Set it to ~25–30% for aggressive trail riding.
• Wipe stanchions clean after every ride to avoid dirt scratching seals.
• Service Intervals: Lower leg service every 40–50 hours of ride time. Full suspension overhaul annually or after heavy abuse.

4. Brakes:

With Magura MT5 four-piston brakes, you get aggressive stopping power. But with great power comes… a need for even better maintenance.

• Pad Inspection: Check every 2–3 rides. Replace when under 1.5mm.
• Rotor Trueing: Bent rotors are common after jumps or crashes — keep them aligned to avoid pulsing or rubbing.
• Brake Fluid: Magura uses mineral oil, not DOT fluid. Bleed every 6 months or if lever feels spongy.
• Avoid touching rotors with bare hands — oils ruin braking surfaces.

5. Fasteners, Frame & Bolts: Check What Keeps You Together

The 775 MX’s rugged 4130 chromoly steel + 6061 aluminum frame takes serious abuse. Keep it tight and sound:

• Torque Check Monthly: Stem bolts, crank arms, brake mounts, motor mounts.
• Inspect Welds: After big impacts or crashes, visually inspect frame joints for cracks or stress lines.
• Bearings & Linkage: Grease pivot bearings every few months, especially in wet or dusty environments.
• Paint Protection: Use clear tape on downtube, chainstays, and areas exposed to rocks/debris.

6. Software & Display Updates

While the Bonnell 775 MX isn’t overloaded with digital features, some models may include motor controller tuning or display firmware.

• Check if your display has update options via USB or Bluetooth.
• Keep up with manufacturer announcements for performance tuning.
• Some riders detune throttle sensitivity or tweak power delivery — make sure you save original settings first.

7. Cleaning: Do It Right

• Never power wash — it pushes water into motor bearings and electrical connectors.
• Use a soft brush and low-pressure hose.
• Avoid direct water on the display, battery port, or brake calipers.
• Dry with microfiber cloth and store in a dry space.

Maintenance Schedule

Ride Hard, Maintain Harder

The Bonnell 775 MX gives you the power, range, and ruggedness to ride anywhere — but only if you keep it sharp. Skip your maintenance, and you risk killing performance, shortening the bike’s lifespan, and compromising safety.

Treat it like a race bike, not a rental.

Keep it clean. Keep it torqued. Keep it charged. And the 775 MX will reward you with miles of unmatched, full-throttle trail dominance.

FAQs

Q1. How often should I service the suspension on the Bonnell 775 MX?
You should do a lower leg service every 40–50 hours of riding and a full suspension service annually or after heavy downhill use.

Q2. What type of brake fluid does the Bonnell 775 MX use?
It uses mineral oil, specifically for Magura MT5 hydraulic brakes. Do not use DOT fluid, as it will damage the system.

Q3. Can I pressure wash the Bonnell 775 MX after a muddy ride?
No. Pressure washing can force water into the motor, bearings, and connectors. Use a low-pressure hose and soft brush only.

Q4. How do I extend the battery life on the 775 MX?
Keep the battery between 20–90% charge, avoid deep discharges, and never store it full or empty for long periods.

Q5. How often should I check bolts and torque on this bike?
A complete bolt check is recommended once a month, especially for the motor mounts, suspension linkage, and brake calipers.