Adding rear disc brake.

[Michael Love]

If I am putting a disc brake on the rear wheel with the motor (bearings replaced, all greased up, waiting to try it out), does the disc sit on the hub with the plastic cover over it or does the plastic cover sit between hub and disc, or, does the plastic (which was there when I unscrewed the screws to put the disc on) not feature at all?
And, if the wheel as you see it will spin counter clockwise, is the disc sitting on the correct side.
Thanks.

 

[flecc]

If I am putting a disc brake on the rear wheel with the motor (bearings replaced, all greased up, waiting to try it out), does the disc sit on the hub with the plastic cover over it or does the plastic cover sit between hub and disc, or, does the plastic (which was there when I unscrewed the screws to put the disc on) not feature at all?
And, if the wheel as you see it will spin counter clockwise, is the disc sitting on the correct side.
Thanks.

The plastic part sits over the disc on the outside, visible when fully assembled. The disc always mounts on the left hand side of the bike, the other side from the chain, so yes, the wheel rotates counter clockwise in forward travel when viewed from the disc side.
.

 

[vfr400]

The writing on the disc should be on the outside. You throw away the plastic part. That's only a spacer to keep the screws in case you don't have a disc.

It's important that you use the correct screws. Don't be tempted to use the nice star screws that normal bikes use because they're too long. Before doing up the screws tight, it's always worth checking that the motor can turn properly, and check again afterwards.

When you install the wheel, you have to check that the caliper is sitting in the middle of the adapter. Normally, that requires an extra 12mm washer on the axle inside the drop-out.

 

[Nealh]

The plastic washer/spacer can be dispensed with if not needed.
You can use it as spacer if you need to bring the disc outboard .
Use it if the screws are long and fouls the motor (for through hole fixings on hub), though better to buy and use correct length screws.

 

[KirstinS]

It's important that you use the correct screws. Don't be tempted to use the nice star screws that normal bikes use because they're too long. Before doing up the screws tight, it's always worth checking that the motor can turn properly, and check again afterwards.

Good advice and something I wasnt aware of a couple of years back. Trashed a motor simply because I changed the bolts to some pretty red anodised ones. My inner bike tart costs me the motor in that case. Lesson learned the hard way!

 

[vfr400]

Good advice and something I wasnt aware of a couple of years back. Trashed a motor simply because I changed the bolts to some pretty red anodised ones. My inner bike tart costs me the motor in that case. Lesson learned the hard way!

I've had to repair two bikes that had those faults. One was done by Halfords when the guy took his electric bike in to have a puncture repaired. They noticed his loose disc and the crappy Chinese screws holding it, so they decided to fix it and replace the screws with their nice star ones. If that wasn't bad enough, they sent the motor wheel to me to find out what was wrong and shipped it in an ordinary cardboard carton. When it arrived, what was left of the motor wire was hanging from the end of the axle, which was sticking through about an inch. The end of the axle was ground down and bashed beyond repair too.

 

[Michael Love]

So, fitted disc, and adjusted inner pad so that it is sitting off disc, but I am getting a bit of squealing, do i have to mive the inner pad a bit further away from the disc?

 

[Andy-Mat]

So, fitted disc, and adjusted inner pad so that it is sitting off disc, but I am getting a bit of squealing, do i have to mive the inner pad a bit further away from the disc?

Neither pad may touch the disk when NOT braking. Sometimes you need to shim the position with thin washers, I had to on my bike, as I was only able to use brand new pads on the "outside". Till I got the caliper correctly positioned, as it was set about a good millimeter towards the LH side....Badly welded position wise...Two small washers, one on each screw between mounting block and the caliper and it was perfect.
It took me a bit of time to get used to adjusting the disks, as I had never had a bike with disk brakes before. Confusing at first, till you see ho it is done
There are some good helpful videos on YouTube and from bike shops if needed.... One of them had to shim as well...
regards
Andy

 

[Michael Love]

It was my stupidity.
I thought the vertical screws had to stay loose to allow the caliper to move, a YouTube video told me how wrong I was.
I apologise for wasting your time.