Assist 20" ebike project / doner bike

zombiemax69

Pedelecer
Aug 31, 2022
42
17
Hey! So i've been offered a Halfords Assist 20" Ebike for £200. My plan is to strip the parts off it and fit to my Son's 20" releigh performance mountain bike. I'm assuming it will be pretty straight forward as its a front motor pedal assist.

Does anyone have a picture of the crank on an assist so I can see if it looks like I will be able to swap over the sensor? or if I'll need to move over the whole crank.

And can anybody think of any potential pitfalls that I'm missing?

Thanks
 

Bonzo Banana

Esteemed Pedelecer
Sep 29, 2019
805
464
Maybe lack of rack mounts possibly on the Raleigh. The Assist will have cut-off brake levers for mechanical disc and V brakes I'm assuming the Raleigh bike would be the same unless its an extra fancy kids model with hydraulic disc brakes. The minimum age to ride a ebike on the road and public parks etc is 14. One thing is the Assist bike has a very small capacity battery so the cells get an extremely hard life so such battery packs may not last the same amount of charge cycles as higher capacity battery packs. So bear this in mind. A few years ago the Assist bikes were sold at sub £300 and with 10% off vouchers and buying discounted gift cards you could reduce that further. The current price is £500 though. It's probably the most basic pre-built ebike you can buy.
 

AndyBike

Esteemed Pedelecer
Nov 8, 2020
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chris667

Pedelecer
Apr 7, 2009
164
108
Spend more money and get a new kit, it will probably be rubbish. If it's old, you will be spending at least what you've paid on a new battery.

Projects like this are fine if you get the bikes free or really cheap, but £200 isn't that cheap.
 

zombiemax69

Pedelecer
Aug 31, 2022
42
17
I bought it in the end... condition is excellent and the battery life is decent. Going to pull it to bits on Monday and try using the parts to convert my Son's bike.

I'm not convinced the pas will fit so may end up fitting an aftermarket one, other than that it looks like it'll work a treat. I think it should be quite nippy too, my son only weighs 25kg and kids bike about 8.5 so the motor will have an easy life.
 

zombiemax69

Pedelecer
Aug 31, 2022
42
17
50899

Well it was fun to put together! It's too fast for him though. Even on the low setting it's really quick... I guess because he's so light. The battery makes it hard to balance too when he stops. Going to try and think of another use for the kit!
 

cyclebuddy

Esteemed Pedelecer
Nov 2, 2016
1,640
770
Beds & Norfolk
It's too fast for him though. Even on the low setting it's really quick...
I'd guess that's because it'll be a cheap speed-capped controller... i.e. even in setting 1 it'll still be full power albeit to a lower than maximum speed. You'd need to change the controller to a torque simulation one to get a lower level of assist power.
 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
20,917
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West Sx RH
For a kit buy light weight 100mm front motor , a small battery either in a saddle bag or in the triangle and a KT 15a controller kit . With the KT one can limit the speed to under 15.5mph, reduce the current so less power but above all they use current control so the start off is gentle and not the harsh /erratic effect of the crappier speed control controllers.

Problem is a bespoke kit might be a bit more expensive then a cheap motor/battery kit but one can tailor it so the parts are right for the job.