Tortola Roundtail – A bicycle frame with a twist

Twin rings said to boost comfort with no loss of efficiency

A Canadian inventor has unveiled a new bicycle frame design that he claims is dramatically more comfortable than a traditional double diamond layout while retaining the same lateral stiffness and pedaling efficiency.


Lou Tortola’s ROUNDTAIL replaces the seat tube and stays of a standard frame with twin hoops of tubing. The idea is that instead of the seatstays transferring impacts and road buzz straight to your posterior, they’re dispersed by the shock-absorbing rings.

Constructed by US bike builder Paul Taylor, of Montana-based Taylor Bicycles, the first alloy frame was unveiled at this weekend’s San Diego Custom Bicycle Show. Apparently titanium and carbon road frames will be available by the time of the Interbike trade show in September, along with mountain bike and hybrid versions.


Tortola cites finite element analysis results that show the design provides 10 times the vertical flex and over 60 times the shock absorption of a traditional frame. That sounds like an awful lot of up and down movement to us. He also reckons it’ll provide aerodynamic advantages. The ROUNDTAIL is said to have passed rigorous fatigue and impact strength testing.