Making my own Boardman Ebike?

[Dog George]

I'm thinking of making up my own Ebike, Using the Boardman Hybrid Pro. What i'm wondering is can i use the original rear gearing & brakes on a Hub motor wheel replacement? As far as i know i'll have to change the front wheel to match the width/tyre size of rear. The bike weight is 9.6kg, I was wondering if i could buy a Hub motor/wheels & Battery pack that would keep the overall weight down? Do you think this idea could work on this model of bike?

 

[D8ve]

Why change the front? Mine is over 6 inch difference in diameter front rear.
Gear can stay the same it depends on the wheel you get.
Disk brakes are recommended as your always going over 10 mph and better brakes can't hurt.
Don't worry too much about weight that's what the motor is for.

 

[Nealh]

I built my own BM mx/cx frim scratch with oxydrive kit so conversion no problem.
For rear hub you will need a cassette hub not a freewheel type, Q100c or 128c hub comes in circa 3kg or a Bafang SWX02c only seen one for sale except 48v on elife bike though there are lighter hubs out there but durability may be an issue depending on the terrain. The battery will also add weight circa 2kg - 3kg depending on how far and how fit you are and the ah needed. Wheel wise rebuild the rear rim with new spokes to keep same as front, A decent independant LBS will lace a electric hub for you if they want business.

 

[Dog George]

Why change the front? Mine is over 6 inch difference in diameter front rear.
Gear can stay the same it depends on the wheel you get.
Disk brakes are recommended as your always going over 10 mph and better brakes can't hurt.
Don't worry too much about weight that's what the motor is for.

I thought about changing the front because the tyres fitted are 700x32 & i might need a wider wheel for a larger tyre say 38/40. It has very good disc brakes fitted as standard that's why i was wondering if i could fit them on to the new rear wheel.

 

[Dog George]

I built my own BM mx/cx frim scratch with oxydrive kit so conversion no problem.
For rear hub you will need a cassette hub not a freewheel type, Q100c or 128c hub comes in circa 3kg or a Bafang SWX02c only seen one for sale except 48v on elife bike though there are lighter hubs out there but durability may be an issue depending on the terrain. The battery will also add weight circa 2kg - 3kg depending on how far and how fit you are and the ah needed. Wheel wise rebuild the rear rim with new spokes to keep same as front, A decent independant LBS will lace a electric hub for you if they want business.

The rear cassette is Sram 10-42T 11 speed, That's why i was wondering if it would fit onto a new motor hub wheel. Thanks for the advice on rebuilding rear wheel i'll talk to my LBS.

 

[anotherkiwi]

Usually you don't need so many gears with a motor. An 11-34 8 speed should be enough and will fit.

32 width tyre would be my absolute bottom limit with a 3 kg hub motor. A fat rear and a skinny front works OK and I have never had anyone come up to me and say "yuck your rims aren't identical" they are both black with silver spokes.

 

[Dog George]

Usually you don't need so many gears with a motor. An 11-34 8 speed should be enough and will fit.

32 width tyre would be my absolute bottom limit with a 3 kg hub motor. A fat rear and a skinny front works OK and I have never had anyone come up to me and say "yuck your rims aren't identical" they are both black with silver spokes.

Thanks for the advice. I thought the 10-42 may help if i was a few miles from home with a flat battery? Plus being Sram quality i didn't want to spend on a replacement that may not be needed.

 

[anotherkiwi]

It depends on your frame whether the 11 speed will fit or not. When I mounted mine it said "maximum 8 speed" and the 7 speed slipped in without having to spread the dropouts. Steel frame yes, aluminium no for spreading wider.

Best bet with an 11 speed would be to mount a mid-drive kit.

 

[Dog George]

It depends on your frame whether the 11 speed will fit or not. When I mounted mine it said "maximum 8 speed" and the 7 speed slipped in without having to spread the dropouts. Steel frame yes, aluminium no for spreading wider.

Best bet with an 11 speed would be to mount a mid-drive kit.

Sorry i've been a bit confused, The 11 speed are fitted to the Boardman already but i've just realized with your last post that the new hub with motor will be consideralby wider?

 

[anotherkiwi]

Yes, a 7-8 speed cassette hub motor is as wide as a stock hub with a 9-11 speed cassette. 135 to 138 mm dropout width. Table here:

http://www.sheldonbrown.com/frame-spacing.html

 

[Deleted member 4366]

You can fit any hub-motor that has a cassette spline. They take up to 10 speeds, but I think I heard that 11 speed cassettes are about 1.8mm longer than 10 speeds. I think that you'd need to change your gearset to a 9-speed to be safe.

You might be safer with a crank-drive, except that you have the PF30 bottom bracket, which makes things tricky. I've seen this adaptor system, but I don't know how well it works or how easy it is to install.

Basically, you have the wrong bike for conversion. Any bike can be converted if you have the skill, knowledge and wherewithal, but I reckon that you'd be better off getting a more standard bike to convert. You don't need anything special when you electrify a bike because the motor compensates for any shortcomings. Buy a used one and save some money.