Rear motor problem

[BLADERUNNER]

Hi all,
i hope that someone can give me some advice.I am trying to convert a Carrera Subway with a 350 Watt Alien off road kit.

With a little bit of tinkering i think it should fit ok.However,when i put the wheel in the rear dropouts it looks to me that the axle is not seated far enough in.I was wondering if it would be ok to file both the dropouts and some of the threads on the axle where it sits in the dropouts just to get a few extra mm.

It is a brand new bike, so as you can imagine i am a liitle nervous about wrecking it, so any advice would be greatly appreciated.

Cheers
Russ

 

[neptune]

First of all, do not file the threads. Or indeed anything. If you post some pictures of the problem, you are far more likely to get helpful advice.

 

[BLADERUNNER]

First of all, do not file the threads. Or indeed anything. If you post some pictures of the problem, you are far more likely to get helpful advice.

Thanks, here is a picture, which i hope illustrates my problem.

 

[jerrysimon]

It looks like it needs to go down a little deeper into the dropouts but that will require filing them out.

An alternative (and you will need to fit one or probably one each side anyway) is to make a steel anti torque arm that bolts to the frame to stop the motor shaft spinning out of the dropouts. If you make it larger then it can have a deeper drop out and make up for the one on the frame which you then won't have to file out.

Looking at the frame there is a hole you can used to attach the new plate plus probably that other cut out in the frame so you can bolt it all securely so it cannot twist.

Regards

Jerry

 

[jerrysimon]

I found a couple of pics which explain it better

PS as stated DO NOT files the threads you will ruin the shaft for the nut to go on!


Jerry

 

[Cyclezee]

Hi Russ,

Cyclezee has torque plates that will do the job for £10 including delivery.



You can find them in our shop here Shop - Cyclezee Ltd

 

[BLADERUNNER]

Thanks Jerry.
That looks like an excellent idea.This solution would solve another potential problem, because if i file the dropouts the disc brake caliper would foul the motor.
I'll have to have a rumage in the shed.
Thanks again.
Russ

 

[Scimitar]

Thanks Jerry.
That looks like an excellent idea.This solution would solve another potential problem, because if i file the dropouts the disc brake caliper would foul the motor.
I'll have to have a rumage in the shed.
Thanks again.
Russ

You don't want to go filing alloy drop-outs for a motor, anyway, if you can avoid it. The steel torque arm is the only way I'd trust a motor on an alloy frame, to be honest.

 

[flecc]

This isn't just a torque plate problem, they are always advisable anyway. It is normally necessary to file the dropouts and I've done this a number of times. The reason is quite simple, normal bike spindles are 10 mm, most hub motor spindles are 12 mm and that is why they don't enter the frame far enough. The difference is very small of course, and generally taking out only a half mm from the front and rear faces of the dropout is enough. That doesn't materially affect the frame strength.

Of course in your case you have that other problem of the disc brake fouling if the motor spindle is properly seated into the frame, but the solution isn't one that would leave me happy.

 

[neptune]

I would seriously consider the torque plates shown by Cyclezee. The advantage of these is that they have spindle hole rather than a dropout slot. Thus the splindle is totally surrounded by metal on all sides. The only downside is that wheel removal will necessitate unbolting the torque plates, a five minute job.

 

[flecc]

I would seriously consider the torque plates shown by Cyclezee. The advantage of these is that they have spindle hole rather than a dropout slot. Thus the splindle is totally surrounded by metal on all sides. The only downside is that wheel removal will necessitate unbolting the torque plates, a five minute job.

It's also possible to use just one part of the eZee torque plate on the rear as this photo of one of my bikes shows:

 

[Fordulike]

I had exactly the same problem as you, but I would not advise filing the drop-outs.
I used 2 of Cyclezee's torque arms, one on each side.
I'm running a peak torque of 68N-m, and have had absolutely no problem.
The torque arms are the dog's danglies

 

[BLADERUNNER]

Thanks to all for advice and suggestions.Wishing now that my bike had V brakes!

 

[aseb]

Have you got it sorted?

I think I have something that might help. I bought 2 of these when I was looking into various ways of fitting torque arms/plates but they aren't really suitable for my front wheel drive but will suit a rear wheel drive. They're laser cut stainless steel and are 3/16" (4.7mm) thick and pretty good.
(I'm intending to post a bit about the torque arms I've tried at some time).

 

[BLADERUNNER]

Have you got it sorted?

I think I have something that might help. I bought 2 of these when I was looking into various ways of fitting torque arms/plates but they aren't really suitable for my front wheel drive but will suit a rear wheel drive. They're laser cut stainless steel and are 3/16" (4.7mm) thick and pretty good.
(I'm intending to post a bit about the torque arms I've tried at some time).
View attachment 3694

Hi i'm all sorted thanks.Ive managed to make a couple of brackets at work.I think ive over engineered them a little, but better to be safe than sorry.I will post a pic when i get the chance.
Cheers
Russ