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 us 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.