By Ben Coxworth November 27, 2012
Tretta's AWD mountain bike
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
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) http://www.gizmag.com/tretta-awd-bicycles/25203/ http://www.gizmag.com/tretta-awd-bicycles/25203/
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All-Wheel-Drive Mountain Bike Test Ride
Posted on September 19, 2012 by Jeff
Here's something You May not have Considered:. An all-wheel-Drive Mountain bike The idea HAS Been Around for Some time-most Notably, Christini . Produces all-wheel-Drive models-but it's something most of U.S. have Never Experienced That's why I had to test ride the Tretta 29er at Interbike.
Looking at the photos you can see how the system works:. A chain attaches to the rear hub on the brake side and runs to the front of the bike at the stem From the stem, a flexible spindle connects to another chain running to the front wheel The front wheel is basically a fixed gear;. even if you're not pedaling, the chain continues to cycle.
The idea behind such a system is that it adds front wheel traction which I can verify from my test ride. It doesn't add as much traction as I thought it would, perhaps because I've learned to keep weight on my back wheel when climbing anyway. Still, climbing into corners, the added traction is apparent.
Now, what I didn't expect was the amount of momentum conservation an all-wheel-drive mountain bike produces. Point this bike downhill and hold on-you'll need a hefty amount of braking power to get the bike stopped.
Similarly, the bike also tends to stay pointed straight down the trail due to the resistance the spindle just below the stem adds. A lot of riders like 29ers because they tend to roll fast once they get going and this takes things to a whole new level ! Just don't try to ride the twisty stuff too fast.
. Of course it's not all sweetness and light This bike is heavy due in large part to the ridiculous chain length (I overheard one guy say the bike must have $ 150 worth of chain) The chain placement is also worrisome;. I brushed my leg against the long chain more than once and I wince at imagining all the ways the chain could get caught in my shorts. Simple, this design is not, which means headaches when it comes to maintenance and repair. It's also not apparent how (or if) a suspension fork might be integrated into this design.
Still, I love seeing interesting concepts and I'm glad I finally got to experience an all-wheel-drive mountain bike. Tretta bikes are not yet available in the US but they've enjoyed a promising response in Japan since their launch at the beginning of 2012. This bike turned a lot of heads at Outdoor Demo and we'll be watching to see how the concept evolves over time.
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