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Richard230
19 October 2010, 1509
Here is an article about four examples of 2-wheel drive motorcycles, only one of which you can buy:

http://www.visordown.com/features/the-2wd-freak-show/14819.html

Now this is more interesting. This article shows photos of a 2-wheel drive conversion kit that you can apparently actually buy:

http://www.visordown.com/features/how-the-christini-2wd-system-works/14826.html

cycleguy
19 October 2010, 1533
I just don't see the advantage of 2WD, given all the added complexity and weight. Especially not on a street bike or racer where the front wheel is off the ground or barely on the ground during acceleration. Perhaps on a trials or enduro bike, even a motocross bike lifts the front when accelerating out of corners.
Most interesting is the possibility of the hydraulic 2WD system being used in a front wheel KERS system for electrics bikes. It seems a much cleaner, less intrusive, and lighter design than the mechanical version used by Chip Yates.

electrician
19 October 2010, 1540
I agree, I don't see any advantage for a street bike.

Although I can see an advantage in motocross where you are doing hill climbing? A hub motor in each wheel with an easily exchangeable battery pack.

teddillard
19 October 2010, 1607
The (theoretical) advantage on an electric bike is that you can run two motors, doubling the wattage, essentially. Or as Two-hub Tony DC puts it, they share the thermal mass.

harlan
19 October 2010, 1607
Here is an article about four examples of 2-wheel drive motorcycles, only one of which you can buy:

http://www.visordown.com/features/the-2wd-freak-show/14819.html


I do remember reading a review somewhere about the two-wheel drive R1 and the reviewer seemed very pleased with the performance.



Now this is more interesting. This article shows photos of a 2-wheel drive conversion kit that you can apparently actually buy:

http://www.visordown.com/features/how-the-christini-2wd-system-works/14826.html

That Christini drive system looks identical to what I saw on the SWIGZ bike at the Battery Show. Either its two-wheel drive and he's not told us yet or he's got some sort of free-wheel gearing to only engage during regen. I do seem to recall he had the regen disconnected during dyno testing, don't remember what the explanation was.



Most interesting is the possibility of the hydraulic 2WD system being used in a front wheel KERS system for electrics bikes. It seems a much cleaner, less intrusive, and lighter design than the mechanical version used by Chip Yates.


When I spoke with Chip and asked why they did not use a hydraulic system he said it was neither as efficient nor as light as the geared system they ultimately chose.

harlan
19 October 2010, 1610
The (theoretical) advantage on an electric bike is that you can run two motors, doubling the wattage, essentially. Or as Two-hub Tony DC puts it, they share the thermal mass.

I think a single motor would be both more efficient and lighter than two motors with a comparable output. The only advantage as I see it is regen in the front, but the unsprung weight and rotational inertia would most likely cancel out any benefit.

Brammofan
20 October 2010, 0544
Here's another article from Visordown yesterday:
http://www.visordown.com/features/is-two-wheel-drive-coming-here/14815.html

I'm betting that Swigz is using it for regen, not for propulsion. Need to come up with a suitable acronym. Not 2WD... more like RWD-FWR (rear wheel drive, front wheel regen).