If you couldn't quite stretch the budget for the HPC Revolution MX and settled for the Bonnell 775 MX, you already know you gave up a few things: a real 5-speed transmission, a hand-built wheelset, a larger USA-built battery, more suspension travel, a 10-year frame warranty, a higher-spec build package, and US-made build quality. The Bonnell is a capable platform on paper, but its biggest day-to-day limitation is fundamental — it's a single-speed. You can pedal up to about 9 mph at a comfortable cadence, and after that you're just ghost-pedaling while the motor does all the work. Hit a steep climb and you have no choice but to mash the throttle. Want to actually pedal at trail speed? On a stock 775 MX, it's not possible.

The good news: you don't have to live with that compromise. The HPC Bonnell 775 MX 5-Speed Electronic Transmission Upgrade Kit retrofits a CYC HD 5-speed gearbox with electronic shifting onto your Bonnell, paired with a hand-built rear wheel on a custom HPC hub. It's the single most impactful upgrade you can do to a 775 MX.

Why the Stock Single-Speed Drivetrain Holds You Back

The Bonnell 775 MX ships with a single-speed setup running a 24T rear sprocket — a design choice that keeps the bike's cost down but creates real-world limitations the moment you ride anything more demanding than a flat fire road. Owners across forums and Endless Sphere have documented the same three problems repeatedly:

• Ghost pedaling above 9 mph. The stock gearing tops out human pedaling input at roughly 9 mph at a normal 70 RPM cadence. Above that, your legs are just spinning air.
• Steep climbs force throttle dependence. With no low gear to fall back on, technical climbs become a battery-drain contest. You can't gear down to climb under pedal power — you mash the throttle and watch your range tank.
• Sprocket swaps are a dead end. Some owners try smaller sprockets to extend their pedaling range, but smaller-tooth sprockets concentrate high torque on fewer teeth — and shear off. DIY 16T sprockets have been documented breaking under hard climbs.

Single-speed is fine for flat trails and casual cruising. But the 775 MX isn't a flat-trail bike — it's a 6,000W trail and moto-style machine with 170mm of suspension travel. It deserves a drivetrain that can keep up. That's where the 5-speed upgrade kit comes in.

What's Inside the HPC 5-Speed Upgrade Kit

This isn't a one-part bolt-on — it's a complete rear-end overhaul engineered as a system. Every component is chosen to handle the full output of the 775 MX without becoming the weak link.

This is the upgrade most 775 MX owners feel first. With five gears to choose from, you can finally match your cadence to your speed. Need to spin up a climb at 8 mph? Drop to first. Cruising at 20+ mph on flat dirt and want to actually contribute to the ride? Click up into fifth and pedal like a real bike.

No more ghost pedaling. No more legs spinning at 110 RPM going nowhere. You become part of the powertrain again — which is the whole point of riding a bike that still looks like a bike.

A 5-speed gearbox gives you something a single-speed can never offer: mechanical advantage on demand. Hit a 25% grade with a loose chunder line? Drop two gears and let the lower ratio multiply your torque at the wheel. The bike claws up grades that used to require full throttle and a held breath.

This is especially valuable for technical riders who want to climb under control rather than just point and pin it. Lower gearing means smoother power delivery, less wheel spin, and more traction on marginal surfaces.

The CYC HD drivetrain doesn't just give you more gears — it multiplies the motor's torque through the gearbox itself. In low gears, you're putting significantly more usable torque at the rear contact patch than the stock 24T single-speed ever could. The 775 MX's X1 Pro motor finally has a transmission worthy of what it produces.

For climbing, technical trail features, log-overs, and steep ledges, this is transformative. The bike pulls instead of slips.

The opposite side of the gearing coin: in fifth gear with a 15T cog, you have meaningful pedaling input at speeds that simply weren't possible before. The bike's top end goes up because you're no longer fighting the gearing — you're working with it. Pair this with the motor and you've got a drivetrain that actually scales with the 775 MX's 40 mph capability.

This is the upgrade owners don't expect — and then can't stop talking about. Every time you have to use throttle to compensate for the wrong gear, you're burning amps inefficiently. The motor is working against a mismatched load. With a 5-speed transmission, you can keep the motor in its efficient RPM band regardless of the terrain.

The result: more miles per charge. Climbs that used to drain 30% of your pack drain 18%. Long rides that used to require a planned mid-route swap can be done on a single battery. You get the same range from a smaller pack, or significantly more range from your existing one.

Here's a detail most upgrade kits get wrong, and it matters: the standard CYC HD aftermarket kit ships with an aluminum freehub driver. On a 6,000W bike putting down serious torque, aluminum drivers are a known failure point — the cassette splines bite into the soft aluminum, deform the driver body, and eventually cause shifting issues or outright failure.

That's why the HPC 5-speed upgrade kit doesn't ship with a generic wheel. It ships with:

• A custom HPC hub with an all-steel driver — not aluminum. Steel resists splining out under high torque and lasts the life of the bike instead of becoming a wear item.
• Thicker gauge spokes for genuine impact resistance and torque transfer without elongation or breakage.
• A wider rim for better tire support, improved cornering bite, and durability over jumps, drops, and rock gardens.
• Hand-built lacing and tensioning done by our wheel builders in Simi Valley, California. Every spoke tensioned, every lateral and radial true checked, every wheel ridden in before it ships.

This is the difference between an off-the-shelf drivetrain swap and a real engineered upgrade. When you spend money on a 5-speed kit, the gearbox should not be bolted to a weak wheel. Ours isn't.

The HPC Build Quality Standard

Hi Power Cycles has been building high-power electric bikes in Simi Valley, California since 2008. Over 20,000 builds. 18+ years. A 3-year warranty on electronics. Every wheel that leaves our facility is laced, tensioned, and trued by hand — not by a machine, not on a factory line, not overseas.

We hold a GSA Schedule contract (47QSMS24D005F) and have delivered bikes to U.S. Special Forces, the Army Corps of Engineers, and the U.S. Air Force. When government customers vet our build quality, it's not because we cut corners on hubs.

That same quality standard ships in every 775 MX upgrade kit — because there's no point in upgrading your drivetrain if the rear wheel can't survive the torque you just added.

What This Upgrade Replaces

Who This Upgrade Is For

• Riders who actually want to pedal their 775 MX, not just twist a throttle on a heavy moto.
• Riders tackling steep, technical terrain who need low gearing and torque multiplication.
• Long-distance trail riders who want measurably more range per charge.
• Owners who've already broken stock components chasing different gearing and want a real solution.
• Builders who don't want to compromise on wheel quality after upgrading the drivetrain.

Frequently Asked Questions

The Bottom Line

You bought the Bonnell knowing it wasn't the Revolution MX. The single-speed drivetrain is the biggest reminder of that compromise every time you ride. The 5-speed electronic transmission upgrade closes most of that gap: it fixes the gearing limitation, it lets you actually pedal the bike, it dramatically improves climbing control, it extends your range, and it does all of this on a hand-built rear wheel engineered to handle the torque you just unlocked.

This isn't a cosmetic upgrade — it's the modification that transforms how the 775 MX rides. And if you're going to keep the bike, this is the upgrade that justifies keeping it.