Converting front hub to rear hub.

[Modbikemax]

I have been wanting a narrow hub motor for the rear wheel but many are too wide for the frames of many bikes.
Many old steel frame road bikes and beach cruisers are made to take a wheel around 120mm axle width and many rear hub motors are 135mm and up. I believe the Q100 motor is the exception for this. I don't like bending the frames too much and it makes fitting the wheel a hassle.
I have a few front geared hubs which are nice and narrow but no way of fitting a freewheel sprocket.
I also have a cheap Quando alloy flip flop hub which has the freewheel threads and plenty of meat for machining.
I started last night and it looks like it could be a goer.
Progress so far

 

[motomech]

And run it backwards, huh?
Sorry, but I see a problem, the axle is too short for any kind of cluster except for maybe a fixie.
There are 2 longer stub axles on the Cute, but they are for the Freewheel/cassette side, hence, no passage for the wires.
I think the CST version could be narrowed easily, just remove the 2 spacer/nuts and trim the spline tube. Add a flat washer to press against the drop-out and one is at 123 mm.
But one would have to custom build a 12 mm narrower cassette.
And, I don't know anything about that.

 

[amberwolf]

Generally this kind of conversion only works with single speed freewheels becuase of axle length. This is my 9C 2807 front as a rear on SB Cruiser:

http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=67833&p=1045514&hilit=+front+rear#p1045514

Which I originally did for Crazybike2 some time ago.

I don't pedal much (at all, really, anymore) but I have verified that it works and has not had any failures of the cover/etc in the times I've used it, including the hard testing I've done on it on the SB Cruiser because I wanna know if it's gonna break I want it to happen now not when I really need it.


Just make sure you put that on teh correct side of the motor, if the geared hub has a freewheel/clutch inside it, or you'll do all that work and end up with a motor that wont' drive the bike forwards, only backwards.

 

[Modbikemax]

I am planning on a single speed setup. For most applications I find a single speed is more than adequate.
I have run into a slight problem with the free wheel. It hangs out a bit far. The nut will only have a few threads because of the cut away for the cable. With a bit of finessing I should be able to make it work.

 

[dogman dan]

In many cases, a rear hub can be made quite a bit narrower by using a single speed, and either modifying a spacer, or notching the axle deeper. Then perhaps still a bit of frame spreading, but not more than 4 mm per side.

Seems to me to be a lot of work, when motors like that are so cheap.

Fun to try it though, just for the grins.

 

[docnjoj]

Somewhere in the threads is a way to extend the axle in a very clever manner and that might help you. Search for "threaded axle extenders" or similar on hub motors.
otherDoc

 

[Modbikemax]

In many cases, a rear hub can be made quite a bit narrower by using a single speed, and either modifying a spacer, or notching the axle deeper. Then perhaps still a bit of frame spreading, but not more than 4 mm per side.

Seems to me to be a lot of work, when motors like that are so cheap.

Fun to try it though, just for the grins.

I bought the Q100 which looks a better choice, but I also have a number of front hubs which I picked up at a fraction of the price of the Q100 and would like to have the option to use as a front or rear.