I have a rear drive motor e bike but it can't get me up some hills. I'm 100kg without much stamina. I have seen on youtube some of the electric mountain bikes in high gears going up pretty steep muddy hills. I'm not planning on going off road but I'd like to be able to get up steep ish hills without much effort, even if it is slowly. I've been thinking to get one of those ebikes with a bosch motor because the bosch motors and their torque are stated on that website, and these bikes say which motor is on them. So I'm wondering with my weight how many NM of torque I will need on one of these motors to get up hills easily? Or even on other motors.
Which motor will get me up hills easily?
- Thread starter lieinking1
- Start date
Post details of what exactly you already have, motor, controller and battery, so that we can propose options.
You need more power, which doesn't necessarily mean you need a new motor. It's not the motor that determines the power you get, it's the controller, and the battery needs to be able to provide the power.
In some cases, you can get what you need with what you have for no additional cost.
Just so we get an idea of the gradient , could you say which hill you are struggling with at the minute ? We can check how steep it is and how much power you would need to get up
Oh it's single gear ! Won't help with steep hills !
Some info here https://www.reddit.com/r/ebikes/s/ap9VdXiT70
It doesn't look an ideal choice for a 100kg rider with limited stamina in hilly areas tbh
Maybe try a shunt mod to the controller ?
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I suspect the fact that it has a torque sensor and you say you have little stamina that is the problem. A Bosch motor won't solve that problem. Also as @Peter.Bridge said, single gear doesn't help either .
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I thought a mid drive motor with gears would solve the problem if it has high enough torque like 70+ NM. Or would that still be a struggle to get up hills?
I get to around this point on this hill before I stop usually. https://www.google.com/maps/@51.4806075,0.0035728,3a,75y,146.35h,69.53t/data=!3m7!1e1!3m5!1sgLr-aeVj_NHyyEp4QTzNYw!2e0!6shttps://streetviewpixels-pa.googleapis.com/v1/thumbnail?panoid=gLr-aeVj_NHyyEp4QTzNYw&cb_client=maps_sv.tactile.gps&w=203&h=100&yaw=321.1282&pitch=0&thumbfov=100!7i13312!8i6656?coh=205409&entry=ttu&g_ep=EgoyMDI0MTAxNi4wIKXMDSoASAFQAw==
OK just over 10% gradient for a quarter of a mile. There's lots of ebikes that will get a 100kg rider with limited stamina up that.
The problem with a torque sensor is that the power that a motor produces is proportional to your pedalling effort - so the less pedalling effort you put in, the less power the motor supplies. I think you would be better off with a cadence sensor, that supplies the power if you are pedalling, irrespective of how much effort you a re putting in.
Also single speed will limit the pedalling effort that you are putting in.
You could get a Bosch motored mountain bike, but they usually have torque sensors, and are quite expensive to buy and maintain- seems a bit over the top for your requirements and you still have the torque sensor to "overcome".
Woosh and Wisper do a range of ebikes that I think would cope with that sort of hill e.g https://wooshbikes.co.uk/?santana3 or if you wanted something cheap and cheerful https://www.electricscooterslondon.com/collections/electric-bikes/products/eleglide-m2-electric-mountain-bike?variant=44804086038752
Or if you wanted a cheap, nearly new , second hand bargain with the super powerful, high torque Aikema motor
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To get full power you need to be pushing fairly hard on the pedals. Having said that it would get you up that hill relatively easily because of the gears. It depends really why you want a bike, if you want to improve your stamina then a torque sensor could be the way to go. If when you first get the bike you need full power in say 3rd gear as your fitness improves maybe you go up in 4th or 5th, then you find you can get up in a lower power level etc.
A mid-drive torque sensor bike still requires some input from the rider, but with the highest torque ones on their highest assistance level in the lowest gear you will not struggle. The rider input demanded is very low. 70Nm will be fine, even more gives you margin.
The worst that can happen is that you buy a bike with say 9 gears, and you feel the need for an even lower gear. That is easily solved by swapping to 10 or 11 speed. I swapped my 11-36 9 speed for 11-51 11 speed and there is nothing I cannot climb.
For reassurance, hire a bike and go ride a big hill. It might cost £50 or £70 , but you will know the answer!
It is not surprising that a single speed, torque sensor hub motor bike does not do what you need. A chunky rear hub, cadence sensor and gears might be enough, but many off the shelf bikes might not be enough.
The way "power" impacts on hill climbing is the speed you get up them, the work in climbing is achieved by the "torque" developed at the rear wheel.
It does typically follow that the more power available tends to also come with higher torque, but as said in respect to climbing it is torque that climbs, power that impacts how quickly you climb.
Hub motors don't share the selectable gearing that bikes can have, here the use of a crank motor can. The crank drive motor's torque can be multiplied by the gearing the bike can feature, just as with a pedal cycle.
In that respect the crank drive motor can have an advantage over the same powered hub drive.
It does typically follow that the more power available tends to also come with higher torque, but as said in respect to climbing it is torque that climbs, power that impacts how quickly you climb.
Hub motors don't share the selectable gearing that bikes can have, here the use of a crank motor can. The crank drive motor's torque can be multiplied by the gearing the bike can feature, just as with a pedal cycle.
In that respect the crank drive motor can have an advantage over the same powered hub drive.
So - for the AKM128 (which I think the Wisper 705 and 905 use) with a max 17 amp controller (which I think the Wispers are set to) would get up a 100kg rider up a 10% hill easily with only 50 watts of pedalling power
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