Disc rotor not aligning with MPIII mounting holes

[Deswr1]

Hi I've just now registered but have been on this forum for a couple if months now, I'm a cyclone bike user but have just purchased a 20" Magic Pie III for a folding bike I've bought. I'm rear mounting it, but the problem I've got is I didn't bother ordering a disc rotor because I've taken it off my existing wheel, its 140mm  6 screw mount type and it doesn't line up properly with the motor holes.
I compared the disc at a shop just to eliminate the problem but it's the motor holes which are out how could that happen ??

[Bikemad]

Hi andto the forum.

There are different standards for disc brake mounting holes which is why GM had two sets of holes on the earlier Magic Pies spaced at different PCDs:



Unfortunately the cooling fan/brake disc mounting assembly on the MPIII was not designed to accommodate both options, so I guess GM simply opted for the most popular spacing to suit their largest market.

If you cannot find a disc locally with the required mounting hole spacing, you may have to order a disc from either GM or one of their dealers.

If your frame also has mounting points to accept a "V" brake mechanism, it would also be possible to simply convert your rear brake using parts from and older bike which can usually be acquired very cheaply from your local scrap yard or recycling centre.

As the MPIII's motor braking is so effective, a "V" brake will be more than adequate for the rear.

Alan
 

[Deswr1]

Thanks for the quick reply I do have v brake mounts but still prefer the disc,I'll properly just order 1 then , I couldn't find anyone talking about this problem in the forum As a lot of people would just use their old disc??

[Bikemad]

I've just checked some measurements, and both the MPIII and the Smart Pie have the six point mount IS2000 standard design with a PCD of 44mm on the disc mounting holes.

The additional option on the earlier MPI and MPII was for a PCD of 48mm.

Alan
 

[MAGICPIE3FOCUSPOWER]

Yes the mounting holes are standard.
I have just re-use my old Avid disc, the alignment is 100%.

[GM Canada]

I have found that all of our motors fit any standard hole configuration on any of our discs or any I have picked up at local stores. One thing I did find odd was I ordered some brake adapters for the 901 and mw16b motors. Please note to use this on a 901 motor you would need a very wide dropout on the rear of your bike. Anyway I was shocked this adapter has non standard holes. None of my discs or anything I could pick up locally fits. GM tells me they have disks to fit these but I did not order them. Now I will wait until mid December to find out if the new disks they are sending me will fit. Here is a picture of the brake adapter. I'll add one of the disk laying on top later to show how they don't line up.

Gary

[Deswr1]

The bike I took the  disc rotor Of is an import from china maybe that's why it wasn't lining up,but the other thing is I took the rotor to the bike shop so they could compare they said it lined up fine ,anyway I've ordered a GM DISC I'll update you when I get it 

[Bikemad]

Gary,

Does that adapter have the holes spaced at 48mm PCD?

Alan
 

[Deswr1]

  Finally got brake disc, the old one is underneath