E-Bike Conversion Kit Installation Guide (2026 Edition)

Step-by-step installation instructions for both hub motor and mid-drive e-bike kits. Tools, torque specs, and pro tips from hundreds of installs.

This is the installation guide we wish existed when we did our first e-bike conversion. It covers both hub motor and mid-drive installations in detail, with the torque specs, connector pinouts, and gotchas that manufacturer instructions gloss over. Bookmark this page — you'll reference it during install and again during future maintenance.

Before starting, gather all your tools and lay out your kit components. Take photos of your bike's original configuration — you'll need them as a reference when routing cables and reinstalling components. Set aside 1-3 hours depending on kit type, and plan to do a careful test ride before trusting the bike for a real commute.

Tools Required

Common tools (most home mechanics own these):
- Allen key set (2-10mm)
- Adjustable wrench (10" or larger)
- Cable ties (100+ in black and white)
- Wire cutters / strippers
- Electrical tape
- Dielectric grease ($5, prevents connector corrosion)
- Bike grease (Phil Wood or similar)
- Torque wrench (3-15 N·m range)

Specialty tools (buy if you don't own):
- Bottom bracket wrench (for mid-drive installs, $15)
- Crank puller (for mid-drive installs, $15)
- 15mm cone wrench (for hub motor axle nuts, $10)
- Cassette lockring tool + chain whip (for rear hub installs, $30)
- Chain tool (for mid-drive chain shortening, $20)
- Multimeter (for electrical testing, $25)

Total tool investment if starting from scratch: ~$130. These are one-time purchases that will serve you for every future e-bike project.

Front Hub Motor Installation (30-60 minutes)

Front hub kits are the easiest e-bike conversion. Here's the step-by-step process:

1. Remove your front wheel. Loosen the axle nuts or quick release, drop the wheel out, and set it aside.

1. Install the motor wheel. Slide the motor axle into the fork dropouts. The motor cable should exit on the left (non-drive) side. Tighten the axle nuts hand-tight for now.

1. CRITICAL: Install the torque arm. The torque arm wraps around the motor axle and bolts to the fork blade. Without it, the motor's acceleration torque will spin the axle inside the dropout, destroying your fork. Use the included torque arm or buy one separately if not included.

1. Tighten axle nuts to 30-40 N·m. Alternate between sides in a star pattern to seat the wheel evenly. Re-check after 50 miles of riding.

1. Mount the controller. Use the included bracket to mount the controller under the down tube, behind the seat tube, or in a triangle bag. Secure with cable ties.

1. Mount the display. Clamp the display to the handlebar within easy thumb reach. Route the cable along the frame using cable ties, away from brake and shift cables.

1. Mount the throttle. Slide the thumb throttle onto the right side of the handlebar, near your grip.

1. Install the PAS sensor. The pedal assist sensor magnet ring goes on the crank arm; the sensor pickup mounts to the frame just behind it. Align them per the kit's instructions (usually 2-5mm gap).

1. Connect everything per the wiring diagram. Most kits use keyed connectors that only fit one way — if it doesn't slide in easily, don't force it.

1. Connect the battery. Verify polarity twice before plugging in. The first connection should be done on a non-flammable surface outdoors.

1. Test before riding. Turn on the battery and display. Lift the front wheel and apply throttle gently — the wheel should spin smoothly without unusual noise. Squeeze the brake levers and verify the motor cuts off (most kits have brake cutoff sensors).

1. Torque-check every bolt after 50 miles. Vibration will loosen axle nuts, display clamps, and cable ties.

Rear Hub Motor Installation (60-90 minutes)

Rear hub installs are similar to front hub, with the added complexity of dealing with the drivetrain:

1. Shift to the smallest cog and remove the rear wheel.

1. Remove the cassette from your old wheel using the lockring tool and chain whip.

1. Install the cassette on the motor wheel. Grease the freewheel threads lightly, thread the cassette on, and tighten the lockring to 40 N·m.

1. Install the motor wheel in the frame. The motor cable should exit on the left side. Tighten axle nuts to 30-40 N·m with torque arm installed (mandatory for rear hubs too).

1. Reinstall the chain. It should be the correct length — if it's too tight or too loose, adjust at the rear derailleur.

1. Mount the controller, display, throttle, and PAS sensor — same as front hub install.

1. Test before riding. Lift the rear wheel and apply throttle gently. Verify the wheel spins the correct direction (forward). If it spins backward, swap any two of the three motor phase wires (usually white, blue, green).

1. Note: rear hub motors make flat tire repairs more complicated. You'll need to disconnect the motor cable to remove the rear wheel. Consider installing a tire liner or slime tubes to reduce flat frequency.

Mid-Drive Installation (2-3 hours)

Mid-drive installs require more mechanical skill but yield the best performance. Here's the BAFANG BBS02/BBSHD process:

1. Remove the right crank arm using the crank puller. Thread the puller into the crank, tighten the center bolt, and the crank will pop off.

1. Remove the existing bottom bracket. Use the bottom bracket wrench to unscrew the drive-side cup (counter-clockwise). Then remove the non-drive side cup (clockwise). Clean the BB shell threads and apply grease.

1. Thread the motor into the BB shell. The BAFANG motor has a threaded boss that screws directly into the BB shell. Hand-tighten first, then use the BAFANG wrench to tighten to 40 N·m. DO NOT overtighten — the motor housing is aluminum and can crack.

1. Install the fixing plate and locknut on the non-drive side. This locks the motor in place against the frame. Tighten the locknut to 30-40 N·m.

1. Install the chainring. The BAFANG kit includes a chainring that bolts to the motor's drive spline. Use threadlocker (blue Loctite) on the chainring bolts.

1. Reinstall the cranks. Use the crank puller in reverse to press the cranks back onto the BAFANG spindle. Tighten the crank bolts to 40 N·m.

1. Size the chain. The BAFANG chainring is typically larger than your original, so you'll likely need a longer chain. Use the big-big method: wrap the chain around the largest cog and the chainring, add two links, and cut. Use the chain tool to break the chain, then connect with the included master link.

1. Mount the controller. The BAFANG controller is usually mounted in a bag under the down tube or behind the seat tube. Some installs integrate the controller inside the battery mount.

1. Mount the display, throttle, and brake cutoff sensors. The brake cutoffs replace or supplement your existing brake levers — they cut motor power when you brake, which is a safety feature.

1. Connect everything per the wiring diagram. The BAFANG harness uses keyed connectors that only fit one way. Route cables carefully along the frame, away from the crank.

1. Connect the battery and test. Follow the same test procedure as hub installs: lift the rear wheel, apply throttle gently, verify the wheel spins forward and the brakes cut the motor.

1. CRITICAL: check the chainline. The BAFANG chainring may sit slightly outboard of your cassette, causing chain rub in the smallest cogs. If you have significant chainline error, you may need a chainring spacer or a different chainring offset.

Post-Install Checklist

Before your first real ride, verify every item on this checklist:

[ ] All axle nuts torqued to spec (30-40 N·m)
[ ] Torque arm installed and tight (hub motors only)
[ ] Bottom bracket locknut torqued to 30-40 N·m (mid-drives only)
[ ] Crank bolts torqued to 40 N·m (mid-drives only)
[ ] Chainring bolts secured with threadlocker (mid-drives only)
[ ] Chain properly sized and shifting smoothly
[ ] Controller mounted securely with no vibration
[ ] Display mounted within easy thumb reach
[ ] Throttle responsive and returns to zero when released
[ ] PAS sensor aligned with crank magnet ring (2-5mm gap)
[ ] Brake cutoff sensors functional (motor cuts when braking)
[ ] All connectors greased with dielectric grease
[ ] All cables zip-tied every 6 inches, no chafing points
[ ] Battery securely mounted, key lock functional
[ ] Tire pressure checked (run max pressure for e-bike loads)
[ ] Brakes adjusted and stopping firmly
[ ] First test ride completed in safe area

Re-torque every bolt after 50 miles, 200 miles, and 500 miles. Vibration will loosen things you wouldn't expect. Mark each bolt with a paint pen so you can spot any that have backed off.