I'm looking for an electric bike. I see motors available on rear, center, and more cheaper, a wheel with a motor to adapt to front. Any experience to help me to make a decision?
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1If this really hasn't been asked before, I think it would be a good question if you fixed spelling, formulated a proper title etc.– NobodyOct 15, 2018 at 18:26
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1This is very close to a duplicate of Center motor ebike costs more, is it worth it? but that question doesn't discuss front hub motors– Chris HOct 15, 2018 at 19:11
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2The beauty of hub motors is their simplicity.– Daniel R HicksOct 15, 2018 at 19:42
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Understand that the different configurations are associated with different modes of operation. Some setups are better suited for just "helping" the rider pedal, others for carrying the entire load.– Daniel R HicksOct 16, 2018 at 1:52
1 Answer
I had a front hub motor in a retrofit kit.
PRO: Its really easy to fit, just leaves a lot of wires hanging on the frame.
CON: Any motor adds weight, and if your bike has suspension it could be unsuspended weight which is not ideal.
CON: The front wheel carries less weight than the rear, so it can slip easier. Powering through a corner is a bad idea, and I even got wheel slip by taking off from the lights with power on and pedalling hard.
My motor was a hard on/off switch, with no sensors or throttle, and was rated at 250W. So you could press the button and just glide with no pedalling.
My general knowledge of pedal assist bikes is that you have to be pedalling to get assistance. This can produce some interesting effects at low speed, when turning under power, and when pushing hard to take off.
A rear hub motor will have the most oomph for the same wattage, but it will add even more weight to the rear of the bike. This can contribute to rear punctures and rear wheel slips when cornering.
A center motor/BB motor distributes the weight evenly between wheels, and keeps the weight low down. However they generally need a special and custom frame.
Don't ignore batteries either - they're always too small in capacity and too big in weight. I had Sealed Lead Acid batteries, and lithium would have been much nicer.
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2I suspect that the weight of the batteries swamps the weight of the motor in most cases. Oct 16, 2018 at 1:52
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@DanielRHicks in my setup absolutely - motor was ~5 kilos, and 7AH SLA batteries were ~3 kilos each, for a total of 9. Add another couple kilos for wiring and controller and battery framing. By comparison a modern Bosch lithium battery is quoted at 2.5 kilos, and 2-3 kilos for the motor (although its not clear how much else is not included in those weights)– Criggie ♦Oct 16, 2018 at 2:44
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@DanielRHicks another related thought - some kits put the batteries on or in a rear carrier rack which is high as well as being quite a long way aft.– Criggie ♦Oct 16, 2018 at 2:46
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1Of course, putting the weight aft is good for traction and control. And high weight is not that much of a problem if it doesn't jiggle around. (After all, the biggest weigh on the bike by far is higher still.) Oct 16, 2018 at 11:34