AWD Dirt Bike

"Scott Keelan" (ScottKeelan) 08/05/2013 at 07:05 • Filed to: TWO WHEELS BAD

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What is Oppo's opinion on AWD dirt bikes? I was watching the X-Games yesterday and learned an AWD dirt bike was competing made by a company called Christini. It's actually a pretty neat story how the company got started and it now even supplies bikes to U.S. military special forces. I know Oppo is mostly opposed to motorcycles but at the very least I thought this was a pretty neat piece of engineering. From Popular Mechanics:

"The front wheel on a Christini motorcycle freewheels, as it would on an ordinary rear-drive bike, unless the rear wheel loses traction. Thus, it acts like a rear-wheel-drive motorcycle until the rear wheel slips—that's why it's AWD rather than 2WD. The front wheel is under-driven compared with the rear wheel, at a ratio of 0.62:1. That means the rear wheel has to be turning significantly faster than the bike's forward speed for the front hub's sprag clutch to engage and begin driving the front wheel. This allows easy cornering, since the wheels can turn at different speeds during a corner. Christini's system uses simple machines to get power from the engine to the front wheel. A chain takes power from the bike's gearbox and routes it through a slipper clutch, then through a driveshaft under the gas tank. The driveshaft pierces the head tube and turns a bevel gearset, which in turn spins shafts that drive stepover chains in the fork crown. A sprocket at each side of the crown turns a telescoping driveshaft in front of each fork leg. Finally, a ring and pinion gearset rotates power ninety degrees to turn the front wheel. The setup adds roughly 12 pounds to the weight of the bike, and Christini says the system saps just 0.1 hp when freewheeling."

Christini Technologies

Satoshi "Zipang" Katsura > Scott Keelan 08/05/2013 at 07:14

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I don't even know what to say.

davedave1111 > Scott Keelan 08/05/2013 at 07:27

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Wow. Just wow. It's like someone looked at the already-complicated systems other people use, and then brainstormed the ways they might make it ludicrously more complicated.

timateo81 > Scott Keelan 08/05/2013 at 08:09

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Good post. Not entirely new in concept - it's been done before with an hydraulic fluid system for the front wheel.

http://www.yamaha-motor.eu/designcafe/en/…

dinobot666 > Scott Keelan 08/05/2013 at 08:50

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They've used a similar system on their mountain bikes for years. It worked pretty well and was generally well received, but was made nearly obsolete by fat tire bikes.

Example:

TeamJeep > Scott Keelan 08/05/2013 at 09:10

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More weight, more stuff to break. It's a neat piece of engineering but I don't really see the real world application.

Dusty Ventures > Scott Keelan 08/05/2013 at 10:23

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Very cool design. I'd be interested in knowing just how much it effects the capability of the bike.

Also Oppo isn't mostly opposed to motorcycles, the whole "two wheels bad" thing is just a long-running joke. You'd be surprised how many people on here ride and how many more are hoping/planning to learn.

mrazekan > TeamJeep 08/05/2013 at 10:39

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You need to ride harder.

Try a super loose, steep, and just nasty hill. There was a pro running one in endurocross for a while.

GasolineLollipop > Scott Keelan 08/05/2013 at 10:40

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I'd love to ride one. I wonder how it does in the sand dunes?

Alex Murel > Scott Keelan 08/05/2013 at 11:44

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Sounds scary as fuck. But I would sell body parts to try one.

Scott Keelan > Dusty Ventures 08/05/2013 at 12:36

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In theory it should ride just like a rear wheel drive bike until the rear wheel loses too much traction, then instead of just spinning one driven wheel the front wheel should scoot the bike along. I think the AWD bike has the biggest advantage on steep inclines. If I'm not mistaken, the AWD bike's superior hill-climbing ability is the reason it's now use by the military.

Also, count me in as a fellow Opponaut that some day aspires to learn/own a motorcycle.

Scott Keelan > TeamJeep 08/05/2013 at 12:42

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The added moving parts is also a concern of mine. Just like any new invention/machine, after many hours and miles of use any week points in the design will get worked out. I have a feeling the average garage mechanic might have a hard time maintaining or fixing an AWD bike himself.

pachood - Cheap rent; fast cars. > Scott Keelan 08/05/2013 at 12:45

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My friend races the Colorado 500 almost every year (for a veeeeeery long time, many big auto racers like Paul Dallenbach race as well) and on several years a manufacturer brought 2wd bikes out for demoing. I dont think Christini is the company, but he said they werent better then ol' trusty rwd.

doodon2whls > Scott Keelan 08/15/2013 at 16:34

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I wish someone would build a 2WD electric motorcycle already with two wheel-hub motors and settle the one vs two wheel drive motorcycle debate once and for all.

90% of the time I was lofting (or at least skating) the front wheel on my Elsinore. 2WD would have just slowed me down.

On a HI-PO street bike, however, I can see where 2WD would be GNARLY.