Some help/pointers with my first conversion

[kettlechip]

Hi guys

I'm an ex- MTB rider who has been out of the scene for a few years after some health difficulties, and seeking to get back into riding, but feel an e-bike would help me build my confidence and fitness to go a bit further.

I'm also on a limited budget, signed off long term and on disability benefits, so on a bit of a budget. I also have a large collection of top quality MTB kit from when I was riding over the years, so am loathe to buy a new bike or convert over to a new wheel size when I have so much legacy kit in 26", which is one of the reasons I think a conversion is the way ahead.

I have two MTB's in the Garage, a Nicolai full suss and a Cotic Bfe hardtail - both running nine speed setups with HG spaced Shimano XT cassettes (also have spare cassettes) one bike running SRAM X.O gears, the other XT, both with triple chain sets and Hope 4pot Discs, plus Fox 36 forks with 20mm bolt through axle.

So, they're my parameters, pretty exacting but I certainly knew what kit suited and worked for me in the past. As you can see, with all that I am seeking the least painless/best value for money way to convert without throwing stuff in the bin.

I'll asso highlight that in large part connected to my health problems I now weigh a bit over 150kg, so recognise that power/torque may be an issue with motors.


So, with 20mm front axles seemingly being out of the question, it appears my obvious solution is a rear wheel motor conversion kit - which needs to be powerful enough to help wind a BUFF up a hill, fit in a 135mm rear spaced frame and run an HG cassette and disc brake hub.

(edit, add a question mark there, as from reading some posts I might be able to fit a bolt on mid motor, is that correct?)

Can anyone point me in the right direction please?

Thanks in advance

Kettlechip

 

[D8ve]

Mid motor is often recommended as it uses the gears to extend the power band. But usually a bit pricier.
Hub motors can cause issues with spokes and unsprung weight. But cheaper.
Torque sensing is what I would suggest suits you it's a power boost in relation to your effort. My old bike power settings were 20 years younger, 20 years old and liar.
rear wheel drive is definitely recommended however you do it.

 

[Nealh]

150kg + the bike weight of about 20 kg is quite a bit of weight for kit to propel. Hub kit wise you may have to look at a 48v/500w set up cobbled together from BMS Battery(China), the battery can be got over here to save import duties or you could look at the Bafang BBS 48V crank drive kits available from Eclipse or Em3ev (HK). BBS will cost 700 - 900 quid though.
Oydrive sell the excellent 36v cassette hub kit, currently on offer for £525 but not sure it will mange the weight load though.
A bit more usage info might help, I assume as in Surrey off road will be the requirement.

 

[kettlechip]

Thanks, yes, Surrey off-road usage but more byways and bridleways (legality understood) than peaslake, if you see what I mean.

The more I read on here the more BBS02 seem to be the answer in order to avoid throwing away/wasting the kit I already have.

Biting the bullet and making £1k tops is just about affordable if I am going do this properly I think, certainly a lot less than spending 3k plus on a new bike.

 

[Nealh]

Go to EM3EV get the 500w 25a BBS02 which is marked 36v/250w should have enough grunt with 25a to tug you along, for the battery source it from the UK so not to have to worry about customs etc or for £700 you could get a 48v/25A BBS02 + battery from Eclipse.

 

[Deleted member 4366]

Em3ev stuff is very good, but not cheap. Cheapest and most suitable hub-motor would be a 48v 201 rpm (code 15 or 16) BPM motor. You'll lose your 9 speed and have to go down to a 7 speed freewheel gear-set. You'd need at least a 20 amp controller to power that

Crank drive might work, but that;s a lot of load going through the gears and chain to haul 170kg or more. BBS02 of some sort would be my choice, but that's not particularly cheap either.

A 48v battery will cost about £300 to £350. How much do you mean by cheap?



To be honest, you'd be better off buying a cheap steel framed MTB already with 6 or 7 speed gears.