Rim drive motors for roadies wishing light assistance; AWD bike possibilities?

Here's a smaller, lighter electric motor, with a novel drive scheme and lighter batteries available, perhaps of interest to those of you with road bikes and very light assistance requirements. Their netsite is appalling (I can't even copy a photo to show you) and the full spec is missing, but it makes interesting reading nonetheless.

http://www.velogical-engineering.com...velospeeder.en

If the product were cheaper, and didn't require non-standard batteries, I might have bought four and fitted them each side of the front and rear wheels for a decent amount of drive in an all-wheel-drive bike, say for riding offroad on grass and loose dirt.

It's another stillborn project, of course, because a bunch of engineers didn't think to bring in a marketer, as the non-standard voltages required by their motor tell us.

I now see that we have another thread on this already, in which Andrew Muzi is even less impressed than me.

On Friday, May 27, 2016 at 10:21:54 PM UTC+1, AMuzi wrote:

Meh.
In Germany a used moped (more power) starts just a bit
higher than that:

http://www.ebay.de/itm/Moped-Hercule...AOSwepZXRx6 7

But people like what they like. Celebrate diversity!

Don't think they're going to like this one enough to put bread on the table, Andrew.

Andre Jute
Couldabeen, a sad story

If they are perfectly synchronized on each side of the rim, that might
work. You will lose some power to additional friction caused by the arc
of the wheel. Probably better than pressing against the top of the tire,
but it's still inefficient friction drive.

You need to track the rim unless it's perfect. Using auto-grip, pressing
the rollers against the rim at the proper attack angle so that the
rollers grip tightly when needed and loosen up when not needed, might
help.


Andre Jute wrote in :

Here's a smaller, lighter electric motor, with a novel drive scheme and lighter batteries available, perhaps of interest to those of you with road bikes and very light assistance requirements. Their netsite is appalling (I can't even copy a photo to show you) and the full spec is missing, but it makes interesting reading nonetheless.

http://www.velogical-engineering.com...velospeeder.en

If the product were cheaper, and didn't require non-standard batteries, I might have bought four and fitted them each side of the front and rear wheels for a decent amount of drive in an all-wheel-drive bike, say for riding offroad on grass and loose dirt.

It's another stillborn project, of course, because a bunch of engineers didn't think to bring in a marketer, as the non-standard voltages required by their motor tell us.

I now see that we have another thread on this already, in which Andrew Muzi is even less impressed than me.

On Friday, May 27, 2016 at 10:21:54 PM UTC+1, AMuzi wrote:

Meh.
In Germany a used moped (more power) starts just a bit
higher than that:

http://www.ebay.de/itm/Moped-Hercule...zum-Restaurier
en-/291774189351?hash=item43ef18cf27:g:gVMAAOSwepZXRx6 7

But people like what they like. Celebrate diversity!

Don't think they're going to like this one enough to put bread on the table, Andrew.

Andre Jute
Couldabeen, a sad story

Yeah, that bears out what I was thinking not long after I posted that, when I started sketching out a control system to make my idle thought work, and a migraine hove over the horizon.

The biggest problem isn't actually two motors on the same wheel, whether one to each side or both to the same side. The biggest problem, when you fit motors to both wheels, is a fast enough equalization response to overspeeding (for lack of a better word) by either wheel in relation to the other, which if not corrected would make the bike unstable, possibly dangerously so. This would happen all the time going around corners, on patches loose gravel on tarmac, on repaired roads with differential friction at every filled pothole, braking, etc.

Thanks for the sobering post...

Andre Jute
"Because I can," isn't a reason to do something, it is merely a temptation


On Saturday, May 28, 2016 at 12:30:34 AM UTC+1, John Doe wrote:
If they are perfectly synchronized on each side of the rim, that might
work. You will lose some power to additional friction caused by the arc
of the wheel. Probably better than pressing against the top of the tire,
but it's still inefficient friction drive.

You need to track the rim unless it's perfect. Using auto-grip, pressing
the rollers against the rim at the proper attack angle so that the
rollers grip tightly when needed and loosen up when not needed, might
help.


Andre Jute wrote in :

Here's a smaller, lighter electric motor, with a novel drive scheme and lighter batteries available, perhaps of interest to those of you with road bikes and very light assistance requirements. Their netsite is appalling (I can't even copy a photo to show you) and the full spec is missing, but it makes interesting reading nonetheless.

http://www.velogical-engineering.com...velospeeder.en

If the product were cheaper, and didn't require non-standard batteries, I might have bought four and fitted them each side of the front and rear wheels for a decent amount of drive in an all-wheel-drive bike, say for riding offroad on grass and loose dirt.

It's another stillborn project, of course, because a bunch of engineers didn't think to bring in a marketer, as the non-standard voltages required by their motor tell us.

I now see that we have another thread on this already, in which Andrew Muzi is even less impressed than me.

On Friday, May 27, 2016 at 10:21:54 PM UTC+1, AMuzi wrote:

Meh.
In Germany a used moped (more power) starts just a bit
higher than that:

http://www.ebay.de/itm/Moped-Hercule...zum-Restaurier
en-/291774189351?hash=item43ef18cf27:g:gVMAAOSwepZXRx6 7

But people like what they like. Celebrate diversity!

Don't think they're going to like this one enough to put bread on the table, Andrew.

Andre Jute
Couldabeen, a sad story

On 05-28-2016 03:45, Andre Jute wrote:
The biggest problem isn't actually two motors on the same wheel, whether one to each side or both to the same side. The biggest problem, when you fit motors to both wheels, is a fast enough equalization response to overspeeding (for lack of a better word) by either wheel in relation to the other, which if not corrected would make the bike unstable, possibly dangerously so. This would happen all the time going around corners, on patches loose gravel on tarmac, on repaired roads with differential friction at every filled pothole, braking, etc.

That would be a problem only when conditions allowed one wheel to slip
on the ground or allowed the friction drive to slip. As long as the
wheel has a firm grip on the road and the motor, friction will force the
motors to go at the appropriate speed.

--
Wes Groleau

On Saturday, May 28, 2016 at 12:07:33 PM UTC+1, W. Wesley Groleau wrote:
On 05-28-2016 03:45, Andre Jute wrote:
The biggest problem isn't actually two motors on the same wheel, whether one to each side or both to the same side. The biggest problem, when you fit motors to both wheels, is a fast enough equalization response to overspeeding (for lack of a better word) by either wheel in relation to the other, which if not corrected would make the bike unstable, possibly dangerously so. This would happen all the time going around corners, on patches loose gravel on tarmac, on repaired roads with differential friction at every filled pothole, braking, etc.

That would be a problem only when conditions allowed one wheel to slip
on the ground or allowed the friction drive to slip. As long as the
wheel has a firm grip on the road and the motor, friction will force the
motors to go at the appropriate speed.

--
Wes Groleau

Exactly, that's what I am saying. A small patch of gravel on the road as you often find at road junctions, where you turn, is the perfect example, where the wheel loses traction and the bike no longer tracks true, becomes unstable, and if it is the front wheel you're gone for sure, and if the rear wheel you're gone unless you are quick.

On one of my bikes, the Gazelle Toulouse, i had a form of mechanical antilock braking, because it was fitted with a disc brake at the front and a much weaker, old-design Shimano Roller brake at the rear (a sort of drum brake).. It worked marvellously well, without a great deal of attention to how I braked, most of the time but the combo wasn't a great emergency stopper. By contrast, my Trek Smover, with best quality, latest, ultra-strong Shimano Rollers front and rear, would stop the bike from elevated speeds on a dime, but was lethal unless you paid attention to your braking.

It would be great if the rim motors made a sort of serendipidous mechanical traction control, akin to the Gazelle's antiskid brakes, but it doesn't seem likely. On the contrary, it seems more likely that the rim motors in all-wheel-drive will aggravate an adverse road condition. This isn't limited to rim motors; I corresponded with a guy who had an electric hub motor in each of the front and the rear wheels and he took some nasty spills.

Andre Jute
Opportuity's inseparable buddy is risk