Author Topic: rear wheel motor: a good idea for me?  (Read 5870 times)

Offline cerewa

  • New Member
  • *
  • Posts: 6
rear wheel motor: a good idea for me?
« on: September 30, 2007, 02:53:25 AM »
I was about to post about how I wanted to get a rear-wheel kit but I wasn't sure it would work out, since I have a bike made for a standard-sized rear wheel. But I received a reply to my question sent to philip from goldenmotor. He said they have fixed the issue with the rear wheel being too wide for standard bicycles.

Quote
Hi Julian,
 
We have already resolved this issue in our factory. The new rear wheel hub motor spacing become 128mm which suitable for most rear wheel bike dropout.
 
Thanks,
 
Philip Yao

I'm excited about getting my rear-wheel-drive electric bike up and running!


I believe my rear dropout spacing is 135mm, but I know from experience that a narrower hub can fit a steel frame with that dropout spacing. You can use washers to take up the extra space. Or just use the torque from the axle nuts to push the dropouts together (no permanent bending of the frame required) although it would be a pain to have do so every time this if you frequently remove/reinstall the wheel.

Here's why I think a rear-wheel motor would be a good idea for me:

I'm figuring if I ride in conditions of questionable traction (Most winters, I use my bike to get to work even when there's snow on the roads) I will want the powered wheel to be the one with more weight on it. Especially when going up a steep hill. Since I expect the motor to be stronger than pedal power I suspect that if it is on the front wheel, it will tend to lose traction going uphill. (and I'd rather lose traction on the rear wheel, since I have had good success recovering from a slipping rear wheel but not from a slipping front wheel.) Not riding in the snow is not such a good option for me, because I can't tell my employer that I only go to work if there is no snow on the roads.

I don't think I will mind having so much placed in the rear of my bike, partly because, say I am braking while going downhill, then a lot of the rider's weight is placed over the front wheel but with the motor and battery weight toward the rear, I will be able to use the traction from both tires to brake a bit better than I could with the weight further forward.

Offline myelectricbike

  • PhD. Magic
  • ******
  • Posts: 644
    • How to Build an Electric Bike
Re: rear wheel motor: a good idea for me?
« Reply #1 on: September 30, 2007, 11:23:54 AM »
What is the date of your reply from Philip?

Offline cerewa

  • New Member
  • *
  • Posts: 6
Re: rear wheel motor: a good idea for me?
« Reply #2 on: September 30, 2007, 12:00:54 PM »
September 29, 9:59PM EST

Offline myelectricbike

  • PhD. Magic
  • ******
  • Posts: 644
    • How to Build an Electric Bike
Re: rear wheel motor: a good idea for me?
« Reply #3 on: September 30, 2007, 03:41:26 PM »
If he is back then maybe he will be catching up on his other email and likewise be responding to other important inquiries...
« Last Edit: October 01, 2007, 08:21:22 AM by myelectricbike »

Offline Dave

  • Confirmed
  • Bachelor of Magic
  • ****
  • Posts: 113
    • davintosh
Re: rear wheel motor: a good idea for me?
« Reply #4 on: October 01, 2007, 04:00:03 AM »
I would certainly be interested in finding out what kind of changes have been made at the factory to get the spacing down to 128mm. That's great news, but the big question I'd have for Philip (which I will be asking) is whether the rim is centered on that 128mm or not. I've been able to get the spacing down on my rear hub, and that is the one detail that's plaguing me at the moment.

Offline myelectricbike

  • PhD. Magic
  • ******
  • Posts: 644
    • How to Build an Electric Bike
Re: rear wheel motor: a good idea for me?
« Reply #5 on: October 01, 2007, 08:37:26 AM »
After Draggin's misaligned axles (BTW - Draggin did Philip send you the replacement kit?) I'm considering for one of my power mods drilling out the pressed axles and using larger ID bearings to accommodate a larger diameter stator keyed center spacer with a larger and hollow stub axle. (BTW - you may want to avoid asking Philip if he can supply factory seconds for such modifications at a reduced price, but if you do and get positive results please cut the rest of us in on the types of defects you encounter and the lower price.)
« Last Edit: October 01, 2007, 08:47:16 AM by myelectricbike »