Sharpbike ebike Rear Hub Motor Cassette 36v 250W Speed + Pedal sensor built in
Next generation high performance hub motors with an interesting addition - a pedal/cassette speed sensor built in as well as the normal wheel speed sensor. You can build this into a bike without having a pedal sensor on the crank. The wire exits from the left hand side, ideal for discreet wiring and safely away from the chain.
Can be used with six hole brake disc or rim brake.
This parts includes a lock ring to hold the cassette, which holds magnets for the pedal/cassette rotation sensor. The lock ring is compatible with an 11 teeth cog only; whatever cassette you use, the smallest cog must be 11 teeth. (You can use the lock ring supplied with your cassette but this will mean the pedal rotation sensor will not function.) A 12 tooth lock ring is not available at this time.
Includes a 10 pin wiring extension to attach to your controller.
36v, 250W, wound for 30mph so suitable for UK & US use.
Happy to help with any questions; we can build this into a full wheel for any size of bike for approx £30 plus the cost of the parts (spokes + rim).
This is UK stock and your item will normally be with you 2-4 days after ordering.
Choosing a cassette
If you want to use the pedal sensor, you must use a cassette with smallest cog of 11 teeth - the pedal sensor magnet holder will NOT work with a 12 tooth cassette. Up to Shimano/SRAM/compatible 10 speed seems to be fine; you may need a spacer for lower numbers of cogs.
When adding a cassette, do not over tighten the cassette lock nut and make sure the lock nut (which contains a rotor with magnets) is rotating freely.
Building a wheel onto this motor
We'll be pleased to help you build a wheel. Spokes need to be ordered based on your specific rim.
https://spokelengthcalculator.com/ is the first place to go. Have a read here and measure the ERD of the rim. This is the radius of the circle that the spoke nuts sit onto.
We have built a 3-cross wheel onto this motor but the spokes are a bit bent out of the rim. Because of the motor radius it looks nicer to build a 2-cross onto 700c / 26" size wheels. You could probably get away with a 1-cross, we haven't tried that yet.
Here are the motor measurements to suit the spoke calculator - you should check these when you get your motor and we can't be responsible for incorrect spoke lengths.
Hub width OLD - 137mm
Right Flange Offset - 51mm
Left Flange Offset - 44mm
Right Flange Diameter - 122mm
Left Flange Diameter - 122mm
Spoke hole diameter - 3.3mm
( Flange width - 5mm )
Spoke Count - 36
The motor is fairly central in the frame so the left and right spokes will be pretty close in length if you're building a 700c or similar size wheel (don't take my advice if you're building for a Brompton!). Pick the shorter spoke length as generated by the calc and order those. For example (don't use these lengths), our left spoke came out at 248.43mm & right spoke at 247.84mm. We ordered 36 spokes at 246mm and that worked just fine. Slightly shorter is also important if you're not lacing the spokes (as recommended).
Other advice - on a 2-cross, the spokes don't need to be 'laced' - the flange is wide enough that they can just pass eachother. Try to start with the spokes going into and across the hub all the way round on both sides, then the ones that come out of the hub last. This avoids bending spokes to get them to cross.
We order spokes from this store - https://www.ebay.co.uk/itm/111217126025