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Author Topic: Michelin patents a possum-scraper electric drive  (Read 857 times)

princec

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Re: Michelin patents a possum-scraper electric drive
« Reply #15 on: January 19, 2021, 11:26:19 PM »

"It handles terribly as a result, but fortunately, when you inevitably stack it into a ditch as a result of its wheelbarrow-like behaviour, it's easy to reverse out."
- More Crap than News

Cas :)
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TheRan

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Re: Michelin patents a possum-scraper electric drive
« Reply #16 on: January 20, 2021, 12:32:26 AM »

When I saw the rear tire friction-drive electric motor patent article I immediately thought of the little generator that you would mount of a bicycle to power a headlight back in the day when I was growing up. The generator was operated by a rubber wheel rubbing against the side of the tire. Kind of makes me wonder how the possum-scraper wheel would get enough traction against the tire tread to move 600-800 pounds of bike and rider in any direction, much less up a grade, which is where it would be needed the most. And as mentioned above, having a relatively heavy weight located behind the rear axle is not something that is going to be appreciated by the motorcycle press reviewers, most of whom are former racers.  ;)
That's pretty much the main issue that kills the idea, you'll need to apply so much force to maintain traction that it's going to require a lot of material (weight) to be strong enough and require a beefy (heavy and awkward) mechanism to engage and disengage the roller. They could increase the size of the roller for more contact area but then you have more weight, an even bigger tumour hanging off the back of the bike, and you'll require an even more powerful motor (even more weight and money) because the bigger roller will have less torque.
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princec

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Re: Michelin patents a possum-scraper electric drive
« Reply #17 on: January 20, 2021, 03:22:50 AM »

I think it probably requires rather less force than you'd think.

Cas :)
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caza

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Re: Michelin patents a possum-scraper electric drive
« Reply #18 on: January 20, 2021, 04:01:12 AM »

People keep saying 'significant unsprung weight' and I don't know if the word 'significant' is true.

-Crissa

Everyone has a different feel for what "significant" can be, but it's just a fact that unsprung weight effects handling. How much it matters to you is going to vary depending on the bike, the rider, the type of riding they are doing, among other factors.

If you look at the sondors metacycle, it has a big hub motor which means unsprung weight that will no doubt effect its handling. But the overall bike is so light and small and intended for light city riding and beginner riders, so I doubt any of its audience would care to notice the handling difference, most of them wouldn't even have a basis for comparison. Ignorance is bliss! Similarly, most scooters have their entire CVT and even the motor built into the swingarm, which is all unsprung weight, but ask a scooter rider if they care.

But the heavier gas bikes that would benefit from this are almost all being ridden by more seasoned riders that know a lot more of the nuance in motorcycling handling, and they would very likely notice and care about the difference. Likewise because they have an overall heavier bike and are going faster speeds, that nuance in handling is going to have a bigger effect on their ride and safety.

And someone who goes to the track is worrying about the alloy of their wheels and the speedholes and material of their rear sprocket, because to them every gram makes a difference.

For my money I wouldn't want to risk bending my starter shaft moving a thousand pound bike but I guess they have it pretty beefy.

As for the OP I think I'd attach it to the swing arm above the chain and let it move the bike from the chain with the bike in neutral.  Just lower a sprocket and turn the chain.  That would avoid the need for tire to roller fiction pressure.

If the small motor is set up for all torque it shouldn't have much problem.  Just like winches that pull out huge Hummers and such.
All torque and very little speed. 

Yeah obviously the starter motor in a goldwing is going to be beefy enough to handle the feature. Bikes are designed as a complete system and Honda took this into consideration, so it's a non-issue.

The chain attachment idea might work but seems just as complex as the patent.

Since when did anyone decide they actually... need something like this?

Cas :)
This is where I'm at. Is it a nice feature to have, sure. But we've gone without it for decades and the sacrifices and cost to produce it don't seem to be worth the marginal benefit nor the obvious downsides.  Even Zero doesn't bother to add it and all they need is software and a button, but it's just not an in-demand feature.

Honda's simpler version of this feature on the goldwing works, and makes sense for that bike, but even they haven't bothered to try to bring it to the rest of their lineup. Even their other DCT bikes don't have that version of the feature.

All unsprung weight is significant, though you'd think by the trend of sticking numberplates and light clusters on iron bars hanging off the back of the rear axles that the current crop of engineers may have finally lost the plot. Probably the same bunch that thought underseat exhausts were a good idea. I imagine they invented inboard ventilated disc brakes and electronic anti-dive at the start of their careers. Don't worry they'll all be dead soon and sanity will return.

Cas :)

Swingarm plate holders aren't going anywhere as long as looks and perceived status drive sales instead of pure practicality and function. It's specifically not an engineering feature but a style feature, to meet DOT regulations without spoiling the "concept" look of a bike. Where form-over -function meets regulation, we get the fender-plate.  Doesn't matter who dies, this design isn't going anywhere.
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DeSelbyofDalkey

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Re: Michelin patents a possum-scraper electric drive
« Reply #19 on: January 20, 2021, 04:32:59 AM »

I want one NOW!

NOW NOW NOW!

Take all my money so that I can get one NOW!

I'M DYING HERE! PLEEEEEEEEASE!

Wait, what is this thread about?

Oh, the fender thing.

Meh.
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JaimeC

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Re: Michelin patents a possum-scraper electric drive
« Reply #20 on: January 20, 2021, 06:23:37 PM »

If you look at the sondors metacycle, it has a big hub motor which means unsprung weight that will no doubt effect its handling. But the overall bike is so light and small and intended for light city riding and beginner riders, so I doubt any of its audience would care to notice the handling difference, most of them wouldn't even have a basis for comparison. Ignorance is bliss! Similarly, most scooters have their entire CVT and even the motor built into the swingarm, which is all unsprung weight, but ask a scooter rider if they care.

This scooter rider DOES care.  Most of the time I don't really notice it on my XMAX, but the first time I aggressively entered a bumpy turn I found myself all over the road and thanking GOD there wasn't a car coming in the opposite direction.  That heavy swingarm/engine/transmission structure absolutely SUCKS at responding to repetitive bumps in turns.  My old TMAX (which mounts the engine in the frame like a motorcycle and drove the rear wheel with an enclosed chain) had no problems on that same stretch of road.

So despite the fact that Yamaha bills the XMAX 300 as a "sport scooter" it is really better at relaxed commuting and touring speeds.
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