Hi, considering a Gas Gas Trials bike conversion with Hub Motor

[bigpie]

Hi from the UK,

I've recently got a Gas Gas TXT 250, it's a noisy 2 stroke, I'm considering converting to electric. My son has an Oset at its great. I think a trials bike might be great for converting, no need to worry about long range, insurance and road legal stuff, DC-DC converters etc and is a fairly light weight machine.

Now the top speed should be fairly modest, but it needs to have quite punchy acceleration. Although I'm not that good at trials riding so it doesn't need to be that competitive.

I'm thinking hub motor for easy of converting.

I'm wondering if something like https://www.aliexpress.com/item/Free...6-72a0984efc58 would be any good for the motor? I was thinking maybe 10-15ah at 48v nominal Hobby LIPO

Or maybe a hobby motor https://hobbyking.com/en_us/turnigy-...___store=en_us

Thoughts/recommendations? My only experience is building a 250W ebike with a brushed motor and my welding was rubbish

[Hugues]

Hi,

i see from the specs of the first one 180 N-m torque, which is not bad for a motor, but for a hub you don't have any demultiplication of that torque. YOu can find electric motors in the 100 N-m range , coupled to a nice belt drive with easily a 4:1 ratio and there you go, you've got 400 N-m on the rear wheel. Or just a chain drive if you don't care about the noise.

[bigpie]

I'm not sure what motors to start looking at if not going for a hub, most that people use in road going bikes seem overkill, I don't need big sustainable power but large peaks will be good. ME1003 I've read a little about might be overkill?

[nedfunnell]

I'm not sure what motors to start looking at if not going for a hub, most that people use in road going bikes seem overkill, I don't need big sustainable power but large peaks will be good. ME1003 I've read a little about might be overkill?

The ME1003 would probably work well. You might also consider the ME0709- I have heard it is the same motor windings with half the commutation area. Lighter and powerful enough for my road motorcycle that goes 70MPH.

[Matej]

If range is not an issue and you want simplicity, low end torque, and acceleration, then it may be better to just go with a small industrial-style brushed DC motor (AMD, D&D, forklift, etc.). The only downside is that it will be a bit heavier than the typical motorcycle conversion motors.

[marcexec]

If range is not an issue and you want simplicity, low end torque, and acceleration, then it may be better to just go with a small industrial-style brushed DC motor (AMD, D&D, forklift, etc.). The only downside is that it will be a bit heavier than the typical motorcycle conversion motors.

or maybe see if you can get a used Agni or Lynch motor? They're designed for EV's at least and torque shouldn't be a problem either.

[bigpie]

Well, I think an update is due.

I went with a D7500 motor from Eastgem and a Kelly KBS controller, 20s lipo pack. 1 to 10 gear reduction (10T front 70T rear)

I've blown the 5v output from the controller so currently using an iphone charger to get 5v for the hall sensors.

It pulls really strongly, I've not tested the top speed or range, it's not built for either.











I will next be using an arduino to measure shaft speed, vehicle speed, pack voltage and battery current draw.