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simon.r
Person
- Location
- Nottingham
Bafang Mid-Drive Installation
- Thread starter simon.r
- Start date
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OP
OP
simon.r
Person
- Location
- Nottingham
11 - Remove chainring and refit the right way round
This improves the chainline and means the screws supplied are now long enough to fit the chainguard.
This improves the chainline and means the screws supplied are now long enough to fit the chainguard.
OP
OP
simon.r
Person
- Location
- Nottingham
12 - Tidy up the cables, refit battery and test ride.
OP
OP
simon.r
Person
- Location
- Nottingham
13 - Set the wheel size / max speed through the display.
OP
OP
simon.r
Person
- Location
- Nottingham
Thoughts, in no order of priority after a brief test ride round the block:
The kit isn’t difficult to fit - I’d say that if you can remove a bottom bracket you’ll be OK fitting this kit.
A longer, hillier test ride is needed to check whether the gearing is low enough.
Given that this bike is almost exclusively used for fairly local shopping trips (< 15 miles) I think I’d look at a lower capacity, physically smaller and lighter battery if I was starting again.
I haven’t fitted the throttle, brake sensors or gear sensor. I didn’t plan to fit the throttle, I can’t foresee a situation on this bike when I’ll be braking and pedalling at the same time and it seems to work well enough without the gear sensor.
I don’t think the brake sensors (where power is cut when the brakes are applied) are a legal requirement - https://www.gov.uk/electric-bike-rules
I need to finish off the battery / motor connection, but can’t do this until the postman brings me the right bits. Apart from that and probably a bit of further cable tidying, the job’s done.
The kit isn’t difficult to fit - I’d say that if you can remove a bottom bracket you’ll be OK fitting this kit.
A longer, hillier test ride is needed to check whether the gearing is low enough.
Given that this bike is almost exclusively used for fairly local shopping trips (< 15 miles) I think I’d look at a lower capacity, physically smaller and lighter battery if I was starting again.
I haven’t fitted the throttle, brake sensors or gear sensor. I didn’t plan to fit the throttle, I can’t foresee a situation on this bike when I’ll be braking and pedalling at the same time and it seems to work well enough without the gear sensor.
I don’t think the brake sensors (where power is cut when the brakes are applied) are a legal requirement - https://www.gov.uk/electric-bike-rules
I need to finish off the battery / motor connection, but can’t do this until the postman brings me the right bits. Apart from that and probably a bit of further cable tidying, the job’s done.
OP
OP
simon.r
Person
- Location
- Nottingham
I need to do something to secure the battery better, but I don’t like the idea of drilling holes in the frame. I may resort to that, but I’ll see if I can think of another way first (which may involve cable ties
). The battery holder came supplied with some spacers shaped to fit the downtube. Thanks for the comment about the fuse, I’ll look into that My electrical skills are minimal, so will be good to do a bit of research and up my knowledge.
I didn't want to drill my bike either, but cable ties did not stop the battery slipping around, and I was worried about theft, batteries are expensive. In the end there was no drama, it was easy, and I bought some stainless steel rivnuts from eBay.
If it is a (legal) 36V 250W motor a 10A fuse should do it. Try "inline fuse holder" on eBay, many are water resistant and even come with a suitable fuse.
If it is a (legal) 36V 250W motor a 10A fuse should do it. Try "inline fuse holder" on eBay, many are water resistant and even come with a suitable fuse.
Ananda
Active Member
- Location
- Athens, Greece
I need to do something to secure the battery better, but I don’t like the idea of drilling holes in the frame. I may resort to that, but I’ll see if I can think of another way first (which may involve cable ties
Thanks for the comment about the fuse, I’ll look into that My electrical skills are minimal, so will be good to do a bit of research and up my knowledge.
If you remove the cover of the battery base plate (where the connectors are) you will see an aluminum plate. Drill this to secure the battery on the frame. You may also want to put some form of rubber between the frame and plate.
Also, on my bafang installation on a bike with hydraulic brakes, I used one of the supplied vbrakes (the left one) as an 'electric clutch' for when I change gears. It works very well. It also gives the ability to cut power during certain maneuvers.
The one and only fly in the ointment with bafang drives is the way they are programmed. You get too much current even at the min assistance level. It can be changed though. But mine is a 750w so yours may be different. As far as the electric throttle goes, I do use mine, especially when starting from traffic lights until I clip to my pedals and also when offroading technical sections.
Your chainring is too large. The motor can turn it, but not without unecessary stress. Lekkie has produced a 40t model that goes with a bling motor cover that helps it fit with correct chainline. What range cassette do you have?
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OP
OP
simon.r
Person
- Location
- Nottingham
Still waiting on the electrical connectors to arrive, then I’ll sort the battery position out. Thanks for the point about drilling the base plate, will look into it.
Interesting idea about the ‘clutch’. Again, I’ll look into that. How have you positioned the lever? Any photos?
After a couple of rides I have come to the same conclusion as you about the chainring. I have a 38t ring on order. Cassette is 11/36. Prior to the conversion I had a 36t chainring. This bike’s obviously not designed for speed, so I think the 38t will be OK.
The Bafang is a pedal assist system. It gives you set amount of extra power per level.
The Tongscheng TSDZ2 is a torque sensing system. It has multipliers of power at each level of effort put in by the rider.
That means setting off is smoother and not a sudden acceleration
The gear selector switch, cuts power momentarily to the Bafang motor allowing a smoother shift. They have two types of switches one for derailleur the other internal geared hubs
The Tongscheng TSDZ2 is a torque sensing system. It has multipliers of power at each level of effort put in by the rider.
That means setting off is smoother and not a sudden acceleration
The gear selector switch, cuts power momentarily to the Bafang motor allowing a smoother shift. They have two types of switches one for derailleur the other internal geared hubs
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Ananda
Active Member
- Location
- Athens, Greece
I hope this helps. Its a convenient place to be despite what it looks in the pic.
The 38t chainring will mess your chainline. The smallest chainring that has a decent offset is 42t. However, it is possible to fit a suitable spacer on the inner side of the freehub and take out one of the smallest sprockets of the cassette. In this way you will bring the biggest sprocket one position out and loose one gear.
Attachments
Bonefish Blues
Banging donk
- Location
- 52 Festive Road
Just by way of an enquiry on a relevant thread, are there any suppliers who will do this type of conversion on your existing bike for you?
Any decent bike shop could do it.
It really isnt difficult though, with a few tools for bottom bracket. I used heat shrink to keep the excess cables tidy, a bit of insulation tape and cable ties.
I took about an hour to swap over to a motor kit. It took a couple more hours to tidy all the cables up and make it a cleaner install.
