Archibald Sharp’s landmark treatise, Bicycles and Tricycles: An Elementary Treatise on Their Design and Construction, published in 1896, describes various contemporary tandem frame designs, including “no-lateral,” in some detail. For decades, this simple, open-frame architecture prevailed; sometimes with the addition of a triangulated stoker compartment. Around the 1970’s, various permutations with internal reinforcing tubes appeared with names such as mixte, full marathon, double marathon, up-tube (popularized by Fisher), all leading up to the currently popular “direct lateral” approach used by most manufacturers today. So, why would Paketa choose to revert back to a century-old design? To put it simply, the open-frame design was selected because our engineering and frame testing development program have proven it’s the optimal choice for magnesium—even Dr. Sharp couldn’t anticipate that advancement in materials. A comparable-weight magnesium tandem frame with a direct lateral tube would suffer in stiffness, strength, dent/buckling resistance, weight, or some combination of these deleterious effects. Archibald would approve.
Check out the new V2r tandem with a unique frame design that allows the belt transfer drive to mount to the right side of the frame, inboard of the main drive. Paketa tandem bikes is located in Colorado, near Boulder. Check your local dealer, or contact us directly if you don’t have a local Paketa tandem dealer.
The Paketa V2r tandem (patent pending) eliminates all of these problems in one elegant, integrated, and game-changing design. By mounting the transfer drive sprocket on the same crank spider, behind the main drive sprockets in the rear, all of the disadvantages of the conventional left-side-drive design are eliminated. Conventional single-bike cranks can be used for both the captain’s and stoker’s cranks, for starters. This allows the use of almost any crank, including state-of-the-art light weight carbon cranks, of any crank length to suit either rider. Because the bearing and axle bending loads are no higher than on a single bike, there’s no stiffness or durability penalty for using the very lightest single-bike cranks available—note the Zipp™ carbon cranks on the V2r in the photos. The transfer drive (Gates Carbon Drive™ belt system shown) is mounted far inboard on the right side, which also reduces frame bending in the boom tube under hard pedaling. Even all-out sprints by the strongest riders won’t cause frame “whip” and the unpredictable handling that results.