Hub motors using disk brakes. Plastic spacer on or off?

[PC2017]

So I noticed the LBS left the plastic spacer on my front hub, when they added a 6 bolt Clarks rotor. I personally installed the motor wheel into the forks & installed as is.

I left the plastic spacer on, as the 26" wheel was rim brakes & the (6) bolt holes go through to the motor insides.

Does anyone omit the plastic spacer front hub or rear motor & have the rotor directly on the hub motor? I was thinking about it because, when aligning the motor in the drop outs I had to slightly washer one side over by 2mm to clear the rotor from the disk brake calliper mounting/forks. Removing the plastic spacer would give me the clearance I need to remove the aforementioned washer & centre the wheel. I am concerned about the 6 bolts going too far into the motor housing if the rotor thickness doesn't stop them.

Any guidance? As normal if that makes any sense...

 

[thelarkbox]

Fwiw the one rotor i have removed from a rear hub drive had no spacer and was attached directly.

 

[Nealh]

Remove it.

 

[saneagle]

So I noticed the LBS left the plastic spacer on my front hub, when they added a 6 bolt Clarks rotor. I personally installed the motor wheel into the forks & installed as is.

I left the plastic spacer on, as the 26" wheel was rim brakes & the (6) bolt holes go through to the motor insides.

Does anyone omit the plastic spacer front hub or rear motor & have the rotor directly on the hub motor? I was thinking about it because, when aligning the motor in the drop outs I had to slightly washer one side over by 2mm to clear the rotor from the disk brake calliper mounting/forks. Removing the plastic spacer would give me the clearance I need to remove the aforementioned washer & centre the wheel. I am concerned about the 6 bolts going too far into the motor housing if the rotor thickness doesn't stop them.

Any guidance? As normal if that makes any sense...

The spacer is for the screws when you don't have the rotor fitted. If you put the screws in without the spacer and rotor, they're too long, so they can jam the motor or even damage the windings.

 

[PC2017]

attached directly

Consensus, it's nice just to cross reference my logic with my peers, once in while.

Remove

On it.

screws when you don't have the rotor fitted

I was thinking they might too short with, rotor and spacer.

 

[saneagle]

I was thinking they might too short with, rotor and spacer.

They would be too short.

In case you still haven't got it:
Disc + spacer = screws too short
No disc, no spacer = screws too long
Disc only = screws correct
Spacer only = Screws correct

You can.of course, use screws with a different length, then you need to make your own arrangements to make sure they go in far enough without damaging the motor. Some motors have blind screw holes, in which case the screws will not tighten if they're too long.