Christini Technologies has just released its first street legal all-wheel-drive motorcycle, the AWD SuperMoto. Unlike similar systems developed by KTM and Öhlins, the Christini conversion is mechanical, relying on a complicated system of drive shafts and chains to move power from the gearbox to the front wheel. The company already offers AWD conversions for Honda and KTM dirt bikes, so not only does this supermoto application make sense, but also it should be available to customers in the near future.
Christini says it uses mechanical, rather than hydraulic,
two-wheel-drive because it results in less power loss. But, with a
complicated system of drive shafts and chains that culminates in a
paired set of telescoping and counter rotating drive shafts driving the
front wheel through a hub-mounted one-way clutch freewheel; we fear
that the lack of power loss will be offset by immense complication.
The system works like this: a chain mounted to a secondary countershaft
sprocket runs up to a gearbox mounted on the main frame rail; that
drives a shaft which runs under the tank to a bespoke steering head;
counter rotating bevel gears located within the head tube transfer
power to the lower triple clamp; two small chains then send that power
out to a counter rotating drive shaft mounted on each fork leg; those
telescopic shafts run down to the front hub, spinning a one-way clutch
freewheel. Ok, we're about half done. Power is sent to the front wheel
at about 80% of the speed of the rear wheel. So when the rear wheel
loses traction, the rear wheel spins faster than the road speed of the
front wheel, engaging the one-way clutch in the front hub and sending
power to the front wheel. A lever on the handlebar allows riders to
discontinue use of the AWD system when desired.
In use, the system works a lot simpler than it sounds, but we still
wouldn't want to try and service the miniscule parts located inside the
frame, steering head and triple clamp.
Testers have reported that permanent two-wheel-drive motorcycles are
able to begin accelerating earlier in corners and harder in slippery
conditions. We're not sure how Christini's system, which only engages
when the rear wheel slips, will differ from that, but expect the same
effects, minus the ability to exploit the added traction before the
rear wheel begins to slip. An analogous system would be the viscous
coupling differential of the Fiat Panda 4x4. While we've found that
vehicle to lack the low, speed stump-pulling traction of mechanical
diff SUVs, it can attack slippery conditions at speed with unrivalled
aplomb. The trick is to never let off the power. We'd expect similar
results from the Christini.
Of course, being a motorcycle, the Christini won't behave entirely like
a diminutive hatchback from Italy. The company claims, "An added
benefit of AWD is that the front wheel does not want to wash out. When
a front end tucks, the wheel stalls, stops turning, and begins to push.
With the AWD system, as soon as the wheel begins to stall, power is
delivered to the front wheel, forcing it to turn. With the front wheel
under power, it is nearly impossible to wash out the front end."
At this point, you're probably thinking the AWD system would make a lot
of sense in a street bike, where its prowess in slippery conditions
could be both a safety and a performance aid. The first step to
achieving that is through road racing; Roland Sands is incorporating
the system in one of his SuperSingles. We intend to find out more.
Christini via Motorcycle-USA