Radical-looking RoundTail bike claims radically smoother ride
By Ben Coxworth
April 13, 2011
If you banged a pole and a hoop against the road, which one would transmit more vibrations to your hand? Given that the flexing action of the hoop would absorb some of the energy, it's probably safe to assume that the pole would give you a numb hand quicker. Well, Canadian cyclist Lou Tortola applied the same sort of logic to the frame design of his Tortola RoundTail road bicycle. Where most other bikes would have a rear triangle consisting of straight seat stays, chain stays and a seat tube, the RoundTail simply has two shock-absorbing joined rings.
Tortola came up with the idea last year, after noticing that many of his fellow long-time cyclists had to quit the sport due to discomfort or injuries caused by riding. Already possessing a background in metals and fabrication, he proceeded to build some sample rings to put his concept to the test. After establishing that there was something to his idea, he got custom bike builder Paul Taylor to create a prototype RoundTail.
The frame was then sent to Boulder, Colorado's Microbac Laboratories, where it was tested for horizontal and vertical loading durability fatigue, and impact strength – on all of which it receiving a passing grade. It was also reportedly found to have ten times the vertical flex of a traditional frame, and over sixty times the shock absorption. Lou additionally suspects that the rings will prove to be more aerodynamic than the straight tubes that they replace.
Of course, road-riding speed freaks don't necessarily want a lot of flex, as any frame that absorbs road vibrations also has a way of soaking up pedaling power. While the RoundTail undoubtedly involves some trade-off in this area, Tortola insists that his bike retains the lateral stiffness and pedaling efficiency of regular bicycles.
The rings do add some weight to the frame, although it's reportedly a negligible amount. "The bike you see in the image weighed in at 17.2 lbs [7.8 kg]," Lou told us. "Material for the RoundTail might weigh 250 grams more than a traditional diamond frame... But at the end, the benefits outweigh that difference for certain."
There's no word on pricing or availability as of yet, although Tortola plans to have titanium, carbon fiber, mountain and hybrid versions of the bike ready for the Interbike trade show in Las Vegas this September. The prototype was officially unveiled at the San Diego Custom Bicycle Show last week.