Bafang Mid-Drive Installation

[simon.r]

I’ve already got the bike and the postman’s delivered everything else I need (I think). Let’s see how it goes.

I’m not planning to post a blow by blow account, but I’ll update this thread with the major points (don’t hold your breath, I’m in no rush to get it finished).

 

[simon.r]

Step 1 - remove BB, cranks etc.

 

[simon.r]

2 - fit the motor.

 

[Nibor]

Where did you get your kit from it looks a very neat solution?

 

[simon.r]

Where did you get your kit from it looks a very neat solution?

The kits are widely available, this particular one came from https://eclipsebikes.com/index.php?cPath=26_27&osCsid=b8d94d67d1b31f90864c2655c6cab2ef , the battery from eBay.

 

[simon.r]

3 - Fit the speed sensor. I’m going to have to move this somehow, as the cable is too close to the tyre.

I want to get it up and running to prove the concept, then I’ll spend some time tidying everything up and tweaking the fitting.

Also worth mentioning that I’m going for a fully UK road legal system - 250W, motor cutting out at 15.5 mph, pedal assist only (no throttle) and motor cutting out when the brakes are applied.

 

[simon.r]

4 - Fit the display and and control pad.

Bafang make numerous different display units. My preference would have been for a more discrete unit (the SW102), but for various reasons I’ve ended up with this one (C965).

 

[simon.r]

5 - Install chainring. The motor means the chainring is much further out, so the chain line is horrible. May try reversing the chainring at some point, but as mentioned before, I want to get up and running, then I’ll start tweaking.

Edit - the chainring is fitted incorrectly. See later post.

 

[simon.r]

6 - Cranks fitted and new chain. The supplied chainring is 46t - with a 36t largest sprocket I needed the full length of the new chain. This bike was fitted with a 36t chainring, so this is going to be a large jump in gearing. Time will tell if the motor makes up for the higher gearing...

There is a plastic chainguard supplied with the kit, which I’ve not fitted at this stage, pending tweaking the chainline (and possible gearing changes).

(Yes, I will make sure that cable’s moved before riding it!)

 

[jowwy]

6 - Cranks fitted and new chain. The supplied chainring is 46t - with a 36t largest sprocket I needed the full length of the new chain. This bike was fitted with a 36t chainring, so this is going to be a large jump in gearing. Time will tell if the motor makes up for the higher gearing...There is a plastic chainguard supplied with the kit, which I’ve not fitted at this stage, pending tweaking the chainline (and possible gearing changes).

View attachment 513026

(Yes, I will make sure that cable’s moved before riding it!)

Why not put the sensor on the non drive side, which will remove some cable slack and move it from the chain and chainring

 

[simon.r]

Why not put the sensor on the non drive side, which will remove some cable slack and move it from the chain and chainring

That sounds like a plan. Thanks.

 

[simon.r]

7 - Fit the battery. The base plate doesn’t line up with the bottle cage bosses, due, I guess, to the non-standard bike I’m fitting it to. One bolt will hold it securely enough for a test run up and down the road, then another problem to sit and think about!

 

[simon.r]

8 - Connect the battery. I don’t have anything to hand to fit what the motor is supplied with. I have some ‘quick release’ connectors on order, so, with apologies to any electricians reading I’ve done a temporary job.

 

[simon.r]

9 - A very short test ride😄. There’s obviously quite a lot of work left to do, but I’m pleased to report that, basically, it works.

To be continued...

 

[shingwell]

with apologies to any electricians reading I’ve done a temporary job.

When you tidy up I would suggest a fuse inline with the battery unless you know the battery has one built in, you really do not want to accidentally short one of those babies. A modern car "blade" type works well.

I had the same bottle holder/battery problem, an M5 Rivnut did the job very nicely https://www.cyclechat.net/threads/variation-on-a-nano-conversion.251868/