They exist. They are specialty, and expensive, and their handling characteristics are decidedly strange. Especially at road speeds. To the very last one they’re intended for use in mucky off-road conditions.
I believe there are also some concept street bikes from the Japanese makers with proposed electric/hybrid part time 2WD systems mostly intended to allow you to launch the things off the line faster without flipping over onto your arse.
On a traditional motorcycle (or bicycle, for that matter) the rear wheel pushes the front. A two wheel drive bike allows the front wheel to pull also, which if you have the front wheel turned significantly and then power is applied to it, i.e. under acceleration, it tends to make the whole bike try to make itself stand upright unexpectedly and throw you to the outside. This has the net effect of widening your turn, which at speed is one of those things that’s likely to result in you making friends with a tree. Or oncoming traffic, depending which way you were turning relative to the road.
You can already wash out the front wheel on a bike by braking, but on a two wheel drive machine there’s also the new and exciting possibility of washing out the front under acceleration, as well. Losing traction on the rear while the front is still pulling in slippery conditions, i.e. those where a two wheel drive machine is most likely to be used, winds up with both wheels ultimately pulling in different directions, especially if the rear hooks up again unexpectedly. This will probably result in an unrecoverable tip-over unless your bike is very light or you’re going very slowly. This may go some way towards explaining why that Rokon bike linked above has a top speed of 35 MPH.
You can sidestep all of this malarkey by getting a sidecar equipped bike with a driven wheel on the sidecar like the various Ural models. These have a freewheeling front like a traditional motorcycle, but a solid axle in the rear that drives both the bike’s wheel and the sidecar’s wheel for snow traction. It’s certainly not impossible to tip over a sidecar bike (especially on the side that hasn’t got the sidecar attached to it) but it’s certainly a damn sight harder than a bike without one.
Also having a powered front wheel can result in you easily losing front wheel traction while accelerating out of a turn, which means you just lost side to side stability at the front while in a lean and you simply fall over.
I know that one from experience on an electric (kick) scooter :)
Very interesting! I’m thinking that the disadvantages you outline are a problem that could be overcome with experience. After all, by definition AWD gives an extra lever of control to the rider. Obviously the crashes by new riders have to be factored into the cost-benefit equation.
If it wasn’t for the icy roads around here during the winter, I would absolutely love one of these.
Wondering when they’ll start making two-wheel drive motorcycles. Something trivially easy for EVs. Not so for gas.
They exist. They are specialty, and expensive, and their handling characteristics are decidedly strange. Especially at road speeds. To the very last one they’re intended for use in mucky off-road conditions.
See also:
The Rokon Trail-Breaker (not street legal, at least not here)
The Yamha WR450F 2-Trac
Also the various Christini 2WD conversions, which have been around for ages.
I believe there are also some concept street bikes from the Japanese makers with proposed electric/hybrid part time 2WD systems mostly intended to allow you to launch the things off the line faster without flipping over onto your arse.
I’ve taken a few dirt bikes for a spin but never a motorcycle. Can you describe what makes the handling strange?
On a traditional motorcycle (or bicycle, for that matter) the rear wheel pushes the front. A two wheel drive bike allows the front wheel to pull also, which if you have the front wheel turned significantly and then power is applied to it, i.e. under acceleration, it tends to make the whole bike try to make itself stand upright unexpectedly and throw you to the outside. This has the net effect of widening your turn, which at speed is one of those things that’s likely to result in you making friends with a tree. Or oncoming traffic, depending which way you were turning relative to the road.
You can already wash out the front wheel on a bike by braking, but on a two wheel drive machine there’s also the new and exciting possibility of washing out the front under acceleration, as well. Losing traction on the rear while the front is still pulling in slippery conditions, i.e. those where a two wheel drive machine is most likely to be used, winds up with both wheels ultimately pulling in different directions, especially if the rear hooks up again unexpectedly. This will probably result in an unrecoverable tip-over unless your bike is very light or you’re going very slowly. This may go some way towards explaining why that Rokon bike linked above has a top speed of 35 MPH.
You can sidestep all of this malarkey by getting a sidecar equipped bike with a driven wheel on the sidecar like the various Ural models. These have a freewheeling front like a traditional motorcycle, but a solid axle in the rear that drives both the bike’s wheel and the sidecar’s wheel for snow traction. It’s certainly not impossible to tip over a sidecar bike (especially on the side that hasn’t got the sidecar attached to it) but it’s certainly a damn sight harder than a bike without one.
Great explanation, thank you. I “felt” the forces and get how it’d cause problems.
If money grew on trees I’d totally get sidecar bike. I’m sure my dog would love it
There used to be sidecars with dogs wearing goggles far more often. That would feels so faraway.
That could be me if they’d just rig the lottery like I’ve been asking
Also having a powered front wheel can result in you easily losing front wheel traction while accelerating out of a turn, which means you just lost side to side stability at the front while in a lean and you simply fall over.
I know that one from experience on an electric (kick) scooter :)
Very interesting! I’m thinking that the disadvantages you outline are a problem that could be overcome with experience. After all, by definition AWD gives an extra lever of control to the rider. Obviously the crashes by new riders have to be factored into the cost-benefit equation.
If you have space, why not get this for the majority of the year and then car for the rest?
Instructions unclear. Have a car, also wound up with seven motorcycles.
I wonder if studded tyres would work out on them. It’s quite effective on bikes, I’m able to bike through winter in Stockholm safely with them.