E-Bike Conversion Kits: Turning the Bike You Already Own
If your bike is decent and your legs aren’t what they were, a conversion kit is the cheapest way into an e-bike. The Bafang BBS02B mid-drive is the one to buy for most people. It drives through your existing gears, which is why it climbs where hub motors give up.
Before the kits, the thing nobody tells you: most of these prices don’t include a battery, and a decent 48V pack often costs as much again as the kit. Budget for both or you’ll end up pairing a good motor with a cheap pack, which is the single worst decision available here.
abouteBikes is reader-supported. We research products from their published specifications and owner feedback rather than testing them ourselves, and the links on this page are affiliate links. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. How we choose what to feature.
Best for what
| Best overall | Bafang BBS02B / BBSHD Mid-Drive | See on Amazon |
| Best hub motor | Bafang 48V 500W/750W Rear Hub | See on Amazon |
| Best complete package | Bafang 48V 500W Front Hub with Battery | See on Amazon |
| Easiest to fit | LIVALL PikaBoost 2 | See on Amazon |
| Best for fat tires | Bafang 48V 1000W Fat Tire Rear Hub | See on Amazon |
| Cheapest wheel kit | Generic 26in 1000W Gearless Rear Hub | See on Amazon |
| What the bottom of the market buys | FONSOLUM 24V 250W Chain Drive | See on Amazon |
Hub or mid-drive: the only choice that really matters
Everything else is detail. There are three types, and they behave completely differently.
| Geared hub motor | Motor in the wheel with internal reduction gearing. Good torque for its wattage, reasonably light, simple to fit. Doesn’t touch your drivetrain. The sensible default. |
| Gearless (direct drive) hub | No internal gears. High top speed, poor low-speed torque, heavy, and it drags slightly when unpowered. A 1000W gearless motor can make less torque than a 500W geared one. |
| Mid-drive | Replaces the bottom bracket and drives the chain, so it uses your gears exactly as your legs do. Far better on hills, better weight distribution, and it wears chains, sprockets and cassettes noticeably faster. |
That torque point is worth sitting with, because it inverts what the listings imply. The generic 1000W gearless kit below makes 45Nm. The Bafang geared 500W makes 65Nm. Half the wattage, half again more pulling power at the speeds you actually climb at.
Will your bike survive it?
Four checks, before you buy anything. Get these wrong and the kit either won’t fit or will damage the bike.
- Dropout spacing. Measure between the inside faces of the rear dropouts. Most bikes are 135mm or 142mm; fat bikes are 170–177mm. The kits below state what they need and they are not flexible about it.
- Brakes. Rim brakes on a bike now doing 25mph with an extra 8kg is asking a lot. Disc brakes aren’t always mandatory but they’re the difference between a conversion and a liability, and some kits, like the fat tire one, refuse V-brakes outright.
- Never a carbon fork. Front hub motors apply twisting force to the dropouts. Carbon does not take that, and the failure mode is the wheel leaving the bike. Steel forks are ideal, aluminum is acceptable with a torque arm.
- Fit torque arms to any hub motor. They’re a few pounds and they stop the axle spinning out of the dropouts under load. This is the most commonly skipped part of a conversion and the most commonly regretted.
The legal bit, which most kits ignore
In the US, an e-bike generally means a motor of 750W or less, with Class 1 and 2 capped at 20mph and Class 3 at 28mph on pedal assist. Fit a 1000W motor that does 33mph and what you have built is not legally an e-bike in most states. It’s an unregistered motor vehicle, which affects where you can ride it, whether your insurance responds, and what happens if you hit someone.
Several kits below are sold at 1000W and quote speeds well past 28mph. They’re included because they’re the right answer for private land, trails where it’s permitted, and fat bikes in snow. Just buy them knowing what you’re building. Our e-bike roundup covers the class system in more detail.
The seven kits
01
Best overall
Bafang BBS02B / BBSHD Mid-Drive
The kit the conversion world is built on. Because it drives the chain rather than the wheel, it uses your gears. Drop into a low one and it climbs anything, which no hub motor at any wattage will match. The BBS02B at 500W or 750W is the sensible version; the BBSHD at 1000W and 160Nm is for people who have stopped pretending it’s a bicycle.
Type
Mid-drive
Power
500–1000W
Torque
120–160Nm
Needs
68–73mm BB
Key features
- 120Nm from the BBS02, 160Nm from the BBSHD
- Throttle, pedal assist and normal riding modes
- Includes brake cut-off sensors, sprocket, throttle, speed sensor and headlight
- Fits 68–73mm, 100mm and 120mm bottom bracket shells
- Color display options including Bluetooth models
What stands out
- Climbs in a way no hub motor does, because it uses your gears
- Weight sits low and central rather than out at a wheel
- Both wheels stay standard, so punctures are normal punctures
What to watch
- Eats chains and cassettes, so budget for a drivetrain roughly annually
- Hardest install here: the bottom bracket has to come out
- Battery and display are both optional extras
02
Best hub motor
Bafang 48V 500W / 750W Rear Hub Kit
If you’d rather not dismantle your bottom bracket, this is the conversion to do. A geared rear hub puts the weight where the bike already carries it, leaves your drivetrain alone, and the install is essentially a wheel swap plus wiring.
Type
Geared rear hub
Torque
65 / 80Nm
Dropouts
135–142mm
Sealing
IPX5
Key features
- Fits 20in, 26in, 27.5in and 700C wheels, 29er compatible
- Takes a 10-speed cassette, works with V-brakes or discs
- Quoted 55dB running noise
- Four pedal-assist modes, several display options
- XT60 battery connector, so check yours matches
What stands out
- 65–80Nm is real usable torque, not a wattage headline
- Leaves the drivetrain entirely alone
- Works with rim brakes if that’s what you have
What to watch
- 750W version tops 28mph, which puts it outside Class 3
- Rear punctures now mean handling a motorised wheel
- Battery sold separately, and the connector must match
03
Best complete package
Bafang 48V 500W Front Hub Kit with Battery
The one that solves the hidden-cost problem, because the battery is a purchase option rather than a separate expedition. A front hub is also the simplest conversion there is. The front wheel has no gears, no chain and no cassette to worry about.
Type
Geared front hub
Torque
65Nm
Fork
100mm QR
Battery
Optional
Key features
- Downtube or rear-rack battery options with locks and USB ports
- 90 percent pre-assembled, with video guides
- Rated to work from −20°C to 45°C, IPX5
- Throttle, pedal assist, walk assist and normal riding
- Fits 20in, 26in and 700C wheels, V-brake or disc
What stands out
- Motor and battery from one seller, designed to work together
- Easiest wheel-swap conversion of the lot
- Keeps the rear wheel and drivetrain completely standard
What to watch
- Front hub on an aluminum fork needs a torque arm. On carbon, don’t
- Front-wheel drive spins up on wet or loose surfaces
- Quick-release forks only, no thru-axles
04
Easiest to fit
LIVALL PikaBoost 2
Not a wheel swap at all. It clamps to the seatpost and drives the rear tire directly, battery built in, no wiring. Fit it in minutes, take it off in minutes, and your bike is a bicycle again, which makes it the only genuinely reversible option here.
Type
Roller drive
Battery
158Wh built in
Range
Up to 31 mi
Fits
25–35mm post
Key features
- No wiring, no wheel building, no tools beyond a clamp
- USB-C PD charging, and it will charge your phone back out at up to 100W
- IPX5, three hours to a full charge
- Built-in warning light, mender included
What stands out
- Completely reversible, with no permanent change to the bike
- Battery included, so the real price is the price
- Moves between bikes in a couple of minutes
What to watch
- 158Wh is a fraction of a real e-bike battery. This assists, it doesn’t haul
- Round 25–35mm seatposts only. Aero or oversized posts are out
- The 65W USB-C charger isn’t included, and this Lite version drops the remote and cruise mode
05
Best for fat tires
Bafang 48V 1000W Fat Tire Rear Hub Kit
Fat bikes need their own kit because the rear dropouts are far wider, and this is the one built for it. Eighty-five newton-meters through a 4in tire is what gets you through snow and sand, which is the whole reason for owning a fat bike in the first place.
Type
Fat rear hub
Torque
85Nm
Dropouts
175mm
Sealing
IPX6
Key features
- Comes as a pre-laced wheel with the motor already built in
- Best sealing on this page at IPX6
- Includes controller, PAS sensor, throttle, brake levers and cables
- Fits 20in and 26in fat bikes
What stands out
- Properly sealed for snow, sand and salt
- Wheel arrives laced, so no wheel-building
- Genuinely fills a gap, since most kits ignore fat bikes entirely
What to watch
- Disc brakes only. V-brakes are explicitly not supported
- 1000W and 45km/h puts the result outside the e-bike classes
- No battery, and the display is a separate purchase again
06
Cheapest wheel kit
Generic 26in 1000W Gearless Rear Hub Kit
An unbranded complete wheel kit at well under Bafang money, and a useful lesson in what wattage does and doesn’t tell you. It’s rated 1000W and claims 33mph, but it’s gearless, so it makes just 45Nm, less than the 500W geared Bafang above. Fast on the flat, lazy on a hill.
Type
Gearless rear
Torque
45Nm
Dropouts
135mm
Load
265 lbs
Key features
- Complete kit: wheel, controller, PAS sensor, throttle, brake cut-off levers
- Reinforced 36-spoke wheel
- Brushless, so no brushes to replace
- 26in wheels with 135mm dropouts only
What stands out
- Cheapest way to a complete motorised wheel
- Brake cut-off levers included, which budget kits often skip
- Fine for flat commuting where torque matters less
What to watch
- 45Nm from 1000W: the weakest torque here despite the biggest number
- 33mph is nowhere near any e-bike class
- Gearless motors are heavy and drag slightly when unpowered
- No brand behind it, so no support and no spares
07
What the bottom of the market buys
FONSOLUM 24V 250W Chain Drive Kit
Included so you can see where the floor is. This is a brushed motor on a mounting plate, driving a freewheel by chain, with a twist throttle and no pedal-assist sensor. It is a DIY part rather than a bicycle conversion, and we would not fit one to a bike we intended to ride on a road.
Type
Chain drive
Motor
24V 250W brushed
Assist
Throttle only
Wheels
16–28in
Key features
- Motor, chain, freewheel, controller, mounting plate and throttle included
- Under-voltage protection at 20V
- Fits a wide range of wheel sizes and DIY projects
What stands out
- Cheapest motorised anything on this page
- Genuinely useful for go-karts, trailers and workshop projects
What to watch
- Brushed motor, so brushes wear out and it is less efficient
- Throttle only, no pedal assist, so it is not a pedelec at all
- No brake cut-off levers, which every other kit here includes
- Mounting is up to you, on a frame never designed for it
All seven, side by side
| Kit | Best for | Type | Torque | Battery |
|---|---|---|---|---|
| Bafang BBS02B / BBSHD | Best overall | Mid-drive | 120–160Nm | Optional |
| Bafang 500W/750W Rear | Best hub motor | Geared hub | 65–80Nm | Optional |
| Bafang 500W Front | Best complete package | Geared hub | 65Nm | Optional |
| LIVALL PikaBoost 2 | Easiest to fit | Roller drive | Not stated | Included |
| Bafang 1000W Fat Tire | Best for fat tires | Geared hub | 85Nm | Not included |
| Generic 1000W Gearless | Cheapest wheel kit | Gearless hub | 45Nm | Not included |
| FONSOLUM 250W | The floor | Chain drive | Not stated | Not included |
Buy the battery properly
Five of these seven arrive without one, and this is where conversions go wrong. A 48V pack with decent cells is a significant part of the total cost, and the temptation after spending on a motor is to economise on the thing that stores the energy.
Don’t. Buy a pack with a proper BMS and a recognized safety certification, check the connector matches your controller (Bafang kits use XT60) and match the voltage exactly. A 52V battery on a 48V controller is not a performance upgrade, it’s a warranty claim. If you want to understand what capacity you actually need, our battery and range guide covers watt-hours properly.
The bottom line
For a bike you like, on roads with hills: the Bafang mid-drive, and accept that you’ll replace chains more often. For a straightforward job on a flat commute: the geared rear hub. If you want to try the idea without committing, or you want to move it between bikes, the PikaBoost is the only one you can undo in five minutes.
And be honest with yourself about the sum. A good kit plus a good battery plus torque arms plus possibly new brakes starts to approach the price of a complete e-bike that arrives working and under warranty. Conversion wins when the bike you own is genuinely worth keeping. When it isn’t, it rarely does.
How we choose
We don’t fit every kit on this site. What we do is read the specification properly (motor type, torque, dropout and bottom bracket requirements, what’s actually in the box) and set it against what owners consistently report. Where a claim looks optimistic, or a wattage figure flatters a weak motor, we say so.
Conversions are also the one area on this site where we’d genuinely suggest professional help. If you aren’t confident removing a bottom bracket or checking a torque setting, the cost of a bike shop fitting the kit is money well spent.
