5-Speed Transmission Upgrade Kit
Step-by-step installation for the HPC single-speed to 5-speed conversion with wireless electronic shifting.
From single-speed to 5‑speed
This guide walks you through converting a single-speed Bonnell 775 MX to the HPC 5-speed transmission with wireless electronic shifting. It's the same sequence we use when we install the kit at our Simi Valley shop: strip the single-speed rear end, fit the new UDH hanger, move your rotor and tire to the hand-built wheel, then set up the derailleur, shifter and chain.
Work in order, use a torque wrench on every spec'd fastener, and finish with the checklist at the end before you ride.
Before you begin
- Power the bike off and remove the battery. A bumped throttle with your hands in the drivetrain can cause serious injury.
- Charge the wireless derailleur and shifter before you start.
- Read every step first. Steps 03 and 11 have an order that matters.
- Not comfortable with torque specs and brake alignment? Have an experienced e-bike mechanic or HPC do the install.
What's in the kit
Hand-built rear wheel
WTB i35 rim, HPC custom 148×12 Boost hub with steel driver, Sapim 12-gauge spokes — built in Simi Valley.
CYC 5-speed CNC cassette
High-strength cassette made for the torque of the CYC mid-drive.
OX wireless derailleur
Custom-programmed for 5-speed, with a strong clutch for chain retention.
Wireless shifter
Push-button handlebar shifter. No cables to route or adjust.
UDH derailleur hanger
Replaces the stock single-speed UDH bracket.
KMC e9 e-bike chain
Heavy-duty e-bike chain, sized to 118 links for this bike.
Tools you'll need
- Bike work stand
- Torque wrench covering 5–25 Nm
- Metric hex keys (4, 5, 6, 8 mm)
- Torx T25 (rotor bolts)
- Quick-link pliers or chain tool
- Tire levers and floor pump
- Brake pad spacer
- Clean rags and isopropyl alcohol
Torque specs
-
UDH hangerStep 0725Nm
-
Rear thru-axleStep 1110–12Nm
-
Axle pinch boltStep 11 — after axle5–6Nm
-
Derailleur mountStep 1410Nm
The finished install
- 1CYC 5-speed CNC cassette
- 2OX wireless electronic derailleur
- 3New UDH hanger + 12 mm thru-axle
- 4Rear brake caliper
- 5Brake rotor (moved from stock wheel)
- 6KMC e9 e-bike chain
Step by step
Teardown
Strip the single-speed rear end
Remove the chain
Find the quick link and open it with quick-link pliers (or break the chain with a chain tool). Lift the chain off the chainring and rear cog. The kit includes a new chain, so the old one is retired.
Remove the chain tensioner
Unbolt the single-speed chain tensioner and set it aside with its hardware. The new derailleur's clutch handles chain tension from here on.
Loosen the brake caliper bolts
Back the two caliper mounting bolts off just enough that the caliper floats. Don't remove them. This makes wheel removal easier and lets you center the caliper on the rotor later.
Remove the rear axle
Loosen the pinch bolt on the drive-side dropout first, then unthread and pull the thru-axle while supporting the wheel.
Remove the wheel
Drop the wheel out of the dropouts, guiding the rotor out of the caliper. Put a pad spacer in the caliper right away.
Remove the stock UDH bracket
Unbolt the stock UDH bracket from the drive-side dropout. Wipe the dropout's hanger interface clean so the new hanger seats flush.
Hanger & Wheel Prep
Set up the frame and the new wheel
Install the new UDH hanger
Seat the new UDH hanger fully against the dropout, with its rotation stop sitting flat against the frame. Tighten the hanger bolt to spec.
Swap the brake rotor to the new wheel
Remove the rotor from the stock hub and mount it on the new HPC hub with the rotation arrow facing the same way. Tighten the rotor bolts to the rotor manufacturer's spec. Keep your fingers and any grease off the braking surface; wipe it with isopropyl if needed.
Swap the tire and tube to the new wheel
Move the tire and tube onto the WTB i35 rim. Check the tire's rotation arrow, look the tube over for damage, and make sure the bead seats evenly all the way around before inflating to your usual pressure.
Wheel Install
Mount, torque and align
Install the new wheel
Remove the pad spacer. Lift the wheel into the dropouts, guiding the rotor between the brake pads and the cassette under the chain line. Slide the thru-axle through and thread it in by hand.
Torque the axle, then the pinch bolt
Order matters. Tighten the rear thru-axle first, then the pinch bolt. Doing the pinch bolt first can keep the axle from seating.
Align the brake caliper to the rotor
Squeeze and hold the rear brake lever so the caliper centers itself on the rotor, then snug the two caliper bolts alternately. Release, spin the wheel, and listen for rub. Fine-tune by eye if needed.
Install the speed sensor magnet
Clamp the speed sensor magnet on a spoke about 4 inches in from the nipple / rim, lined up so it passes directly over the sensor on the frame. Spin the wheel to make sure it clears.
Drivetrain & Setup
Derailleur, shifter, chain, calibration
Install the derailleur
Thread the OX derailleur onto the new UDH hanger, check that it hangs straight and parallel to the cassette, and tighten to spec.
Install the shifter
Mount the wireless shifter on the handlebar where your thumb reaches it without leaving the grip. It ships custom-programmed for 5-speed operation.
Install the chain
Route the KMC e9 chain over the chainring and cassette, then through the derailleur's upper and lower pulleys. Make sure it sits inside the cage tabs. The correct length for this bike is 118 links. Join it with the quick link and load the pedal to snap it fully closed.
Calibrate
Wake the derailleur and shifter and open the rear derailleur gear parameters in the derailleur's app. Enter the baseline values shown here for gears 1 through 5 and tap Save parameters. Then turn the cranks in the stand and run up and down through all five gears. If the chain hesitates, chatters or won't settle on a cog, nudge that gear's value up or down in small steps and save again until every gear runs quiet. Confirm it can't overshift past the largest or smallest cog.
- Gear 10
- Gear 2150
- Gear 3302
- Gear 4473
- Gear 5607
Final checklist
- Every torque value re-checked: 25 · 10–12 · 5–6 · 10 Nm
- Wheel spins freely with no rotor rub
- Rear brake lever is firm and doesn't pull to the bar
- Tire bead seated evenly and inflated
- Chain quick link fully closed
- All 5 gears shift cleanly up and down under load
- Speed shows on the display when the wheel spins
- Battery reinstalled and locked in
Download the PDF guide
All 17 steps, torque specs, diagrams and the final checklist in a printable 7-page PDF.
Stuck on a step? Call us.
We've installed this kit on the 775 MX in our Simi Valley shop, and we're happy to walk you through it.
- Emailsales@hpcbikes.com
- Webhpcbikes.com
- Shop4180 Guardian St #106, Simi Valley, CA
Always follow the component manufacturers' instructions and torque specs where they differ from this guide. Hi Power Cycles is not affiliated with Bonnell; product names are used for fitment reference only. Ride off-road and within local laws.