An all-wheel-drive mountain bike? We're kidding, right? Actually no, we're not. This is the Christini Long Travel, and it offers the rider the ability to dramatically improve off-highway traction by simply flipping a switch to drive the front wheel in addition to the rear wheel. Here's how it works:
On the rear wheel hub is a rear spiral gear (think ring-and-pinion), which spins a tubular aluminum multisection driveshaft that is mostly hidden in the frame and fork of the bike. The torque is transferred through these driveshafts to the front wheel where the power is conveyed to the front wheel via the front spiral gear (again, think ring-and-pinion). So let's say you're blasting down a dirt trail and you come to a long, muddy section. You simply engage the AWD system via a handlebar-mounted switch that controls the shift-on-the-fly clutch. As soon as you do so, the rear spiral gear interlocks with the rear hub and power is transferred to the front wheel. The moment the rear wheel slips, power is instantaneously transferred to the front wheel. Technically, you could leave the system in AWD, because due to a slight gearing differential, the front wheel is not actively powered on smooth, level ground when in AWD and the bearing-supported system produces very little friction.
This is the front spiral gear that transfers the power from the driveshaft to the front wheel. The spiral gear is comprised of an aluminum bevel and pinion gear.
It's all pretty simple, huh? It appears that way, but the reality is that Christini Technologies spent years perfecting this technology. They point out that companies have been attempting AWD systems on bicycles since the early 1900's, but it wasn't until the mid 1990's that Steve Christini finally perfected and patented the concept and made it commercially viable.
You're probably wondering how much the Christini AWD weighs. After all, it has to weigh a ton, with all of the U-joints, driveshafts, and spiral gears, right? Wrong. This particular model weighs just 31 pounds, and of that total weight only 2.7 pounds is attributed to the AWD system. That's impressive.
Another impressive aspect is that this is a full-featured bike with all of the goodies one would expect in a serious mountain bike. It has an adjustable front and rear suspension, Hayes front and rear mechanical disc brakes, and high quality Shimano derailleurs.Bottom line: The Christini Venture Long Travel is a unique machine with capabilities far beyond a standard mountain bike. With this baby those sketchy trails won't seem quite so intimidating.
On this cutaway image you can see a portion of the tubular aluminum driveshaft. The 'shaft uses two U-joints and three gearsets to help transfer power to the front wheel.
Model: Christini Long Travel AWD
Base price: $3,100
Colors: Blue, red, or black anodized
Size: 16-, 18-, or 20-inch
Frame: 6061 aluminum with sealed cartridge bearing pivots
Rear shock: Manitou SPV 200mm shock with 100-150mm adjustable travel
Fork: White Brothers VT 1.3 with 80-130mm adjustable travel
Headset: Christini integrated with sealed bearings
Crankset: Shimano XT
Front derailleur: Shimano XT
Rear derailleur: Shimano XT
Shifter: Shimano XT
Chain: Shimano HG
Hubset (f/r): Proprietary Christini silent, zero-backlash freehub/proprietary Christini
Spokes: DT Swiss double-butted
Rims: Mavic 317 disc, black
Tires: Kenda Claw, 2.1-inch width
Brakes (f/r): Hayes mechanical disc/Hayes mechanical disc
Brake levers: Hayes
Pedals: N/A
Handlebars: Titec Hellbent
Grips: Titec Go-Go
Stem: Titec Rip 3-D
Seatpost: Titec
Saddle: WTB