Bicycles

Tretta AWD Bicycles put that lazy front wheel to work

Tretta's AWD mountain bike
Tretta's AWD mountain bike
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Tretta's AWD mountain bike
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Tretta's AWD mountain bike
Tretta's AWD city bike
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Tretta's AWD city bike
Tretta's AWD cyclocross bike
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Tretta's AWD cyclocross bike
Tretta's AWD beach cruiser bike
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Tretta's AWD beach cruiser bike
Japanese bicycle manufacturer Tretta is looking at selling its 2-wheel-drive bicycles in North America
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Japanese bicycle manufacturer Tretta is looking at selling its 2-wheel-drive bicycles in North America

Although they’re very seldom seen, 2-wheel drive bicycles have existed in one form or another almost as long as their traditional rear-wheel-drive counterparts. While most of them have been one-off experiments or short-run production models, Japanese bicycle manufacturer Arte Co Ltd has decided to give the 2WD thing a shot nonetheless, with its Tretta AWD Bicycle line-up.

Tretta AWD bikes have been available in Japan since the beginning of the year, but just made their U.S. debut this September at the Interbike trade show in Las Vegas. While there are no immediate plans for North American availability, the Interbike appearance was aimed at gauging stateside receptivity to the rather unusual bicycles.

Pedaling power is delivered to the rear wheel using the usual right-hand-side crankset/chain/cassette arrangement. On the non-drive side of the rear hub, however, is a cog that drives quite a long chain. That chain stretches from the rear hub up to a set of small cogs located near the top of the down tube.

A much shorter chain goes from those cogs to yet another cog, mounted on an arm that extends from the head tube. A flexible universal joint connects that cog to another one, that is mounted on an arm that is attached to (and that turns with) the front fork. Finally, a third chain extends from the cogs/universal joint down to a drive cog on the front wheel hub.

It’s a set-up that’s difficult to describe, and that Arte unfortunately hasn’t provided any close-ups of, but it’s what allows the system to work even when the front wheel is turned to one side.

Tretta's AWD beach cruiser bike
Tretta's AWD beach cruiser bike

The Tretta bikes were initially designed to provide Japanese commuters with increased traction in adverse weather such as snow and rain, although the applications for mountain biking are pretty obvious, too. Unfortunately, all those extra chains and cogs add to the bike’s weight and will require more maintenance, plus they can’t be used with a suspension fork.

It also looks like that one long chain could rub against the inside of the rider’s leg – that problem and other limitations may be addressed in future versions of the bikes, according to a representative from the company.

Tretta buyers in Japan can currently choose between mountain, cyclocross, beach and city models. They range in price from ¥33,000 to ¥75,000 (about US$402 to $912).

Source: Tretta (Google translated from Japanese)

27 comments
DemonDuck
You don't get something for nothing. That front wheel will cost you energy. And have you ever peddled up a mourtain trail. It's already hard and your front wheel is bouncing around anyway with most the weight on your back wheel. Maybe it's better -- maybe not....
Jeffrey Weckman
I see many problems with this design. ... And I am a bike mechanic. No thanks.
Milton
I like the simplicity of the design, Too bad it does not allow for any suspension, even still I feel like it could easily be implemented on those large-wheel (Surly?) bikes. As for the second drive-chain rubbing on the riders leg, I wonder why they didn't run all of them from the crank instead of from the rear cog (like they seem to have done with the "city bike". I wish there were more photos (or info) on how the bicycle turns. I imagine this design doesn't allow for very much handle-bar movement.
The Hoff
The only traction you need in rain is for braking. This is no mountain bike, you can barely turn it, and they run great without 2 wheel drive anyway. on a steep hill front wheel drive will not help. Snow and soft sand... maybe, but it needs a huge chain guard.
Mike MacDonald
Just replace the chains with 1/4" shafts, use larger, but a telescopic shaft for the front forks and you can have All Wheel Drive {AWD} with suspension, done well, less weight {Carbon Fiber} !!! There are heaps of helical gears that would do the transfer, already on the market.
EvanJD
I think drive-by-wire would be a good idea as opposed to a mechanical system like that which is being used for this design, obviously the drive-by-wire system has to be married into the pedal, cog and chain configuration.... that's my thought though, if it can be done it will cancel out the need for all those extra chains and such, which honestly are unsightly and not really revolutionary!
Steve Pearson
AWD bikes are already available through companies such as Christini (www.christini.com). While the bike described here is cheaper than a Christini, that AWD system looks very cumbersome and possibly dangerous. Are they going to shroud all of those chains so there is no chance of clothing or body parts getting caught? Not only that, but no suspension? I applaud the designers for their attempt, but this is not a bike I would ever buy. If I was that desperate for an AWD bike I'd pay the extra and get something like a Christini.
Michael Mantion
This is a joke right? I mean I have seen a lot of front wheel drive systems and this HAS to be a joke. No one in their right mind would take this serious.
Pikeman
When you go around curves your tires take different paths and that means that they travail different distances so tying them together will eat a lot of energy and greatly increase tire wear. There is a good reason that 2 wheel drive bike are rare they are a bad idea.
Aaron Lieberman
Not very useful if you know how to ride. And it would't work on mountain bikes due to the suspension movement, which would require too many pulleys and be too cumbersome.