Author Topic: fitting rear motor kit to 135mm spacing  (Read 17150 times)

Offline emzed

  • Confirmed
  • New Member
  • *
  • Posts: 20
Re: fitting rear motor kit to 135mm spacing
« Reply #15 on: August 13, 2007, 12:41:55 PM »
Hi Macbeth, thanks for your input.

The rear wheel I took of my bike is dished by about 8mm and the right spokes aren't quite vertical. I wans't sure how close to vertical you could go. So based on that, given there is about 27mm gap on the motor hub, the max offset from dishing would be half that (~13.5mm) with the right spokes vertical.

I have ordered a 3 gear cluster to see how that goes...

Offline Dave

  • Confirmed
  • Bachelor of Magic
  • ****
  • Posts: 113
    • davintosh
Re: fitting rear motor kit to 135mm spacing
« Reply #16 on: September 18, 2007, 02:05:47 AM »
Hey emzed; any progress on your rear wheel kit?

Offline emzed

  • Confirmed
  • New Member
  • *
  • Posts: 20
Re: fitting rear motor kit to 135mm spacing
« Reply #17 on: September 19, 2007, 10:59:27 AM »
Hey Dave,

Yeah. Heres a summary of what i've done
- I got my 3 gear cluster
- turned down the spacer tubes in the lathe
- ground down axle to extend the flats as required
- replaced the rim with a double wall rim
- replaced the tube with a puncture proof one
- replaced the tyre with a better one
- got the bike shop to respoke/dish the new rim as required ( I think it needed about 4mm)
- made a torque arm for one side

My setup has the plain slotted washers on the inside of the dropouts. I still have to make a torque arm for the other side. I gave it a quick run with only the one torque arm as i'm a bit eager to get it going. I am quite impressed with the power and quietness!

I did have my batteries on a pannier rack on the back but it made the bike soooo back heavy it was ridiculous. So I am currently making a bracket to hold the batteries between the seat post and the front forks.

More pics to come, sorry for the delay

Offline Dave

  • Confirmed
  • Bachelor of Magic
  • ****
  • Posts: 113
    • davintosh
Re: fitting rear motor kit to 135mm spacing
« Reply #18 on: September 19, 2007, 11:36:47 AM »
Thanks for the update and the photos; looks good so far! Nice job on the torque arm. Are the dropouts on your frame aluminum or steel?

I'm following similar steps in getting mine going, but haven't swapped out the rim. I've got the spacing down to 135mm, with the flats extended to match. I also had a bike shop dish the wheel for me -- they moved it about 5mm, but it's still not centered in the frame. The threads on the spokes were a bit too short to go any farther without replacing spokes. I've been thinking of taking the 3 speed gear cluster route (but haven't yet done anything with that thought); where did you find yours?

Offline myelectricbike

  • PhD. Magic
  • ******
  • Posts: 644
    • How to Build an Electric Bike
Re: fitting rear motor kit to 135mm spacing
« Reply #19 on: September 19, 2007, 12:15:24 PM »
That looks and sounds like an awful lot of work so let me remind you to be sure to keep those axle nuts tight and check them before every ride. I didn't and now I'm gonna pay. Also be alert to the possibility of any internal corrosion. I had only ridden mine maybe 20 or 30 times before mine began to seize due to internal corrosion either from rain, puddles or motor cooling off sucking in warm moist to form dew inside the next morning. With the steel yoke, aluminum yoke spokes and steel axle and bearings and aluminum cover and steel stator the aluminum is going to go first like sacrificial zinc. Not much you can do except pop the covers every now and then or possibly drill a few small holes (1/8")for venting and draining around the covers at the level of the head of the cover screws. Anyway hope it holds up for all the work. Looks nice, great job.


Offline emzed

  • Confirmed
  • New Member
  • *
  • Posts: 20
Re: fitting rear motor kit to 135mm spacing
« Reply #20 on: September 19, 2007, 12:29:58 PM »
I'm from Australia so I bought my 3 gear cluster from here http://www.users.bigpond.com/solarbbq/bikesale/bsale.htm He sells Crystalyte hubs but was extremely helpful with some queries of mine.

My entire frame is Aluminium.

Offline emzed

  • Confirmed
  • New Member
  • *
  • Posts: 20
Re: fitting rear motor kit to 135mm spacing
« Reply #21 on: September 19, 2007, 12:33:31 PM »
Oh yeah, and I bought a thumb throttle while I was waiting for my hub kit to arrive, but after my first ride (with the twist throttle) I think the twist throttle will be heaps easier with the reen controller. For some reason I thought the regen controller worked a bit differently. Ideally I would like a thumb throttle on the right hand side and a thumb 'regen brake' on the left and true freewheeling when no assist is being used.

Offline myelectricbike

  • PhD. Magic
  • ******
  • Posts: 644
    • How to Build an Electric Bike
Re: fitting rear motor kit to 135mm spacing
« Reply #22 on: September 19, 2007, 01:00:18 PM »
As I recall both throttles use a linear Hall effect sensor with +5 volts being zero RPM and 0 volts being 300+ RPM. Maybe you could devise a circuit that could detect variable freewheel voltage level and then use that to set the bottom of the throttle and the top of the brake. Say for instance by matching freewheel at 100 RPM you might set top of brake and bottom of throttle to +3.1 volts and then at 200 RPM to +4 volts, etc. That way no matter what speed you are traveling your TOB/BOT voltage will still give you braking for one and throttling for the other.
« Last Edit: September 20, 2007, 02:22:06 AM by myelectricbike »

Offline mustangman

  • Confirmed
  • Bachelor of Magic
  • ****
  • Posts: 221
Re: fitting rear motor kit to 135mm spacing
« Reply #23 on: September 19, 2007, 11:43:13 PM »
Nice bike emezed!!! :)