Bafang BBS01B Crank Drive Kit

Why choose a crank drive?

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The Best Choice for Hills

A hub motor delivers a fixed torque — fine on flat roads, but it struggles on steep inclines. A crank drive motor powers your chain directly, so your gears do the work. You can climb 10% gradients on throttle alone, and steeper hills with gentle pedalling.

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Natural, Flexible Riding

The cadence sensor means you can ride without worrying about gear changes — you can literally ride without a chain or never change gear. If you have any physical difficulty with pedalling, cadence assist is generally the better choice over torque sensing.

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Panasonic Battery Cells

All our BBS01B kits come with batteries made using top-quality Panasonic cells — the same brand used in premium electric vehicles. Two battery shapes available (HL and DP), both fitted to your downtube. The DP gives you about 17% more capacity.

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UK-Supported, Fully Warrantied

We sell complete kits only — motor, battery and charger together — so everything is matched and tested. If we can't fix a kit under warranty, we'll offer a refund. Kit enquiries go to kits@wooshbikes.co.uk.

Which voltage?

BBS01B — 36V

Standard torque · cadence sensor + throttle

Smooth, reliable everyday assistance
Great for moderate hills and flat roads
Cadence sensor for easy, flexible riding
Throttle for direct power on demand
250W OEM, road legal

BBS01ET — 48V

Higher torque · cadence sensor + throttle

Stronger assistance on steep hills
Better performance for heavier riders
Cadence sensor for easy, flexible riding
Throttle for direct power on demand
250W OEM, road legal

Not sure which to choose? As a rule of thumb — if you live somewhere hilly or are a heavier rider, go for the 48V. For general commuting on gentle gradients, the 36V is excellent value.

Battery options

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HL Battery

Standard downtube bottle battery. Slimmer profile, fits most frames.

361 × 90 × 92 mm

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DP Battery

Slightly larger downtube battery — gives you about 17% more capacity for longer range.

368 × 95 × 103 mm

⚠️ Please email us a photo of your downtube before ordering so we can confirm which battery fits your frame.

Installation overview

Remove your existing bottom bracket

You'll need a crank puller and a bottom bracket removal tool. If you can remove your bottom bracket, you have everything you need. A C-spanner to tighten the M33 lockring is also useful.

Fit the motor

The BBS01B replaces your bottom bracket and chainring. The motor exits downwards — allow clearance below the frame. Tighten the first M33 lockring very firmly.

Mount the battery on your downtube

You may need to drill two M5 rivnuts on the downtube to secure the battery cradle — a 6.5mm drill bit is all you need. Both HL and DP batteries fit the downtube.

Connect the wiring

Minimal wiring: connect the battery, LCD display, and throttle. All connectors are push-fit waterproof. If you have hydraulic brakes, you'll need our hydraulic brake sensors (£16 per pair).

Fit the LCD and throttle to your handlebars

You'll need space on your handlebars. If you have combined gear/brake levers or hydraulic brakes, hydraulic brake sensors will be needed.

⚠️ Golden rules for installation

Cable from the motor must exit downwards
Do not pull cable ties too tight
Make sure the motor connector is inserted all the way to the line
Do not use a pressure washer on this kit
Installation time: approximately 2 hours

Technical Specifications

Bafang BBS01B — Specifications
Motor	Bafang BBS01B bottom bracket crank drive
Power	250W OEM (EN15194 certified, road legal)
Voltages	36V (BBS01B) or 48V (BBS01ET)
Sensor type	Cadence sensor + throttle
Battery cells	Panasonic (top quality)
Battery options	HL (361×90×92mm) or DP (368×95×103mm)
Battery fitting	Downtube (both shapes)
Brake sensors	Hydraulic brake sensors available: £16/pair
Bottom bracket	68–73mm shell (standard)
Kit includes	Motor, battery, charger (whole kit only)
Installation time	Approx. 2 hours
Tools required	Crank puller, bottom bracket tool, C-spanner
Gear sensor	Not supported on current stock
Reprogramming	Not supported — voids warranty
Warranty	Full warranty — refund offered if unrepairable

Frequently asked questions

Will it fit my bike?

The BBS01B fits bikes with a standard 68–73mm bottom bracket shell. Before ordering, please email us a couple of photos of your bike (or tell us the model) to kits@wooshbikes.co.uk. We'll check compatibility before you buy — no nasty surprises.

Do I need hydraulic brake sensors?

If you have hydraulic brakes or combined gear/brake levers, yes — you'll need hydraulic brake sensors (£16 per pair). If you have standard cable brakes, the inline brake sensors included in the kit are fine.

Can I fit it myself?

Yes, if you're reasonably mechanically minded. You'll need a crank puller and a bottom bracket tool. The most challenging part is usually removing the old bottom bracket. Installation takes around 2 hours. We also have a network of local technical helpers across the UK who can assist — ask us for details.

How do I change gears with a crank drive motor?

It's straightforward once you know the trick: briefly squeeze one brake lever for a moment to cut the motor, change gear, then throttle up again — just like changing gears in a car. It becomes second nature very quickly.

Can I get a gear sensor?

Our current BBS01B stock does not have a socket for a gear sensor, so we are unable to supply one for this kit.

What is your warranty and returns policy?

Full warranty is included. If we cannot fix a kit under warranty, we will offer a refund — though this will be based on the condition, age, and mileage of the kit. Please see our Sales Conditions for full details. Note: faults caused by incorrect installation or misuse are not covered.

How do I enquire?

For kit enquiries, please email kits@wooshbikes.co.uk with a couple of photos of your bike and any questions. This is because it's not possible to remember everything discussed on the phone after several conversations. All prices include shipping to UK addresses.

Enquire About This Kit

Email your questions and bike photos — we'll check compatibility and advise.

Kit enquiries by email please — include a couple of photos of your bike (or the model name) and we'll advise before you buy. All prices include UK delivery.

✉️ kits@wooshbikes.co.uk

— or call us —

📞 01702 684444

Bafang BBS01B