Commuter rebuild

[sal_park]

Hi,

my commuter is currently going through a rebuild and I thought I'd record the details in this thread.

Here's what it looked like before:

It's a 250w bafang fun8 front hub that I installed around 18 months ago. Unfortunately this noise turned out to be the motor having eaten the grub screw that you need to take the motor case apart. I found a youtube video showing how to take the case apart, but apon inspection of my motor I could see the grub screw *hole*, but no grub screw. The 2 parts of the case were loose (causing around 5mm play at the tyre) however I could not get the case to turn. I didn't use the proper tool, but with my home-made one was able to exert enough force to chip the case, but not open it... so onto plan B.

Plan B involved replacing the motor with a rear drive BPM 500W kit from bmsbattery.com. Here are some pictures from the build.

Just before starting:


Here is the existing bastardation of 2 racks - the black one was already on the bike when I install the first ebike kit, and the sliver one is where the battery goes:
View attachment 18

Here I've started to remove the silver rack and test fitted the new controlled (old controller was in silver metal box ahead of the battery:


I had to remove some metal from the black rack to mount the new controller, and drilled some holes to mount it (with ny-lock nuts)

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But I still need to re-fit the silver rack a bit:


I've now removed the silver rack from the bike and the silver metal box where the old controller was:
View attachment 12
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Now I need to make a little hole in the metal box to allow all the new cabling in from the controller:


And super glue some rubber around it so I don't damage the cables:


Here is the box re-installed, looking from the underside of the silver rack:
View attachment 8

Now it's on to fitting the rear wheel:


It pretty much fitted ok first time. I had to re-fit it several times when it became apparent other things were not fitting correctly...

Next thing to fit was the torque arm - I test fitted it, planning to secure it to the caliper mount post. A bit of blue tack made marking where to drill much easier:

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First reason to remove the wheel: best to remove this packing piece before putting on the brake disc


I had a few other hickups - I bent the anti-rattle shim in the caliper and didn't add enough packing washers on the axle first time round, but after all this, here is the money shot:

 

[sal_park]

(hit max picture post limit).

So now I'd proved it all works, it's time to put it together properly.....

I've added some tape to tidy up the cables before the go into the silver box:
View attachment 11

And had to extend the bolts that connect the rear of the silver rack to the back one:


This is the silver rack in it's new position attached to the black one with the controller sandwiched between:


...and now with the silver metal box installed too:



Something that always annoyed me with my previous build was the mess of wires on the top tube. I'm trying to neaten them up here by using some cable trunking from a DIY store that I had lying around. I'll probably spray it black to make it look a little neater:

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View attachment 2

And now here is the finished article, well finished for the moment anyway I'll probably need to do some fine tuning on it but good enough for the moment.

 

[bilabonic]

What size rear cassette did you fit mate ?

I have been informed it needs to be 7 speed to fit between drops ?

Also are those hydraulic brakes ? Did you fit sensors to them ??

Cheers

 

[sal_park]

What size rear cassette did you fit mate ?

I have been informed it needs to be 7 speed to fit between drops ?

yep, it's a 7 speed, spin on gears (can't remember the correct name - gears and freewheel all in one). I've got a 14teeth - ~34teeth (super crawler or something) which was the easy option, but not the best. You can get an 11teeth - something sensible which is much better suited to an ebike.

Also are those hydraulic brakes ?

yes

Did you fit sensors to them ??

Not yet, although I do plan to do this.