By Andrew Liszewski
Bikes designed for off-road trail riding feature thick tires and robust suspension systems to cushion the rider from all the bumps and vibrations they encounter. But road bikes, which are designed to be low-profile and light, are lacking such amenities. And unless you exclusively ride on a perfectly smooth track in a velodrome, you’re still going to encounter pot holes and other bumps on a road. The traditional bike design we all know and love features a triangular rear frame, which unfortunately is quite effective at transferring vibrations and bumps from the road to the rider. Which can lead to fatigue and soreness. So inventor Lou Tortola (who hails from my hometown) started to rethink the traditional road bike design.
What he came up with was a pretty simple, but radical improvement on their design. Instead of keeping the bike’s overall diamond geometry, he replaced the rear part of the frame with a set of circular rings. It changes nearly nothing about how the bike goes together or how it operates, but has a dramatic effect on how it rides. With the RoundTail frame, vibrations and shocks from the road are transferred to the two metal circles, where the energy follows along their circumference until dissipated. Instead of traveling up to the rider. In tests, the RoundTail frame has been found to absorb 60 times more vibrations from the road than a standard frame, allowing riders to spend more time riding before they start feeling any discomfort.
[ Tortola RoundTail Bike Frame ] VIA [ Popular Science ]
That looks so heavy.
there have been concepts like this before – the problem is that they inevitably make pedaling slightly less energy efficient too, which is always noticeable to the rider.
you can’t lose vibration energy in the drivetrain without making it harder to pedal
having ridden the roundtail i can say that the vibrations really are reduced, the bike is light for steel and of course could be lighter in carbon or al or ti… it is peppy and responsive and it really smooths out the road. i am convinced it would be a fabulous touring bike and i would snap one up in a minute for a long ride. i also have to say they are prettier in person than in photographs.