No company has pushed the boundaries of contemporary chassis technology more than Bimota in terms of both materials and design. The company co-founded almost 40 years ago by the recently-retired Michelangelo della Moto, Massimo Tamburini, has done it again with the debut of its DB7 Oronero superbike. In creating the world's first production motorcycle with a structural carbon fiber chassis, Bimota retains its place at the leading edge of frame design. Even if achieving that entailed borrowing techniques and technology from another form of two-wheeled transportation.
All of this came as a direct consequence of Bimota technical director Andrea Acquaviva's personal involvement in another form of two-wheeled sport-one that doesn't use engines. "I've been a keen cyclist for many years," declares Acquaviva, "and because of my work at Bimota I've always been interested in the carbon-framed bicycles used by the world's top riders. So, after production of the DB7 got started, it seemed a good idea to look at replacing the steel tubes used in that chassis with carbon fiber ones, to reduce weight further without sacrificing rigidity."
Luckily for Acquaviva, the owner of B.R. Bike Research in Cesena (producing bicycles under the "Switch Bike" brand), a few miles north of Rimini, was an avid motorcyclist. B.R. owner Giancarlo Biondi was already exploring ways to adapt his bicycle technology to a motorcycle application when Bimota contacted him, and had constructed a Monster S4RS carbon frame weighing a remarkable 10 pounds, in contrast to the stock Ducati steel chassis scaling in at more than 30 pounds. Acquaviva commissioned B.R. to manufacture a composite equivalent of the DB7 frame, resulting in a weight savings of over 15 pounds from the already featherweight 375-pound standard DB7.
The Oronero chassis are manufactured at the rate of one per week, using a sock of woven dry-lay carbon/Kevlar fabric which is sleeved around previously formed, individually-shaped polyurethane patterns-some of which may be tubular, others not-before resin is added to provide stiffening, while also facilitating addition of the struts and fasteners to create a structure with an exceptionally strong stiffness to weight ratio, thanks also to internal carbon bracing via techniques which B.R. has led the world in developing.
The tubes are internally braced with a cruciform carbon fiber strut for added rigidity-a unique technology developed by Biondi-and are fitted at each end with inserts machined from solid billet Ergal 55 aircraft-grade aluminum, then bonded to the carbon tubes. This carbon/Kevlar spaceframe is bolted to twin sideplates flanking the rear cylinder, made of Anticordal 100 aluminum. The same treatment has been carried out on the 525mm-long swingarm, which is made from oval-section carbon/Kevlar tubing that's supported by Ergal inserts in meeting the rear axle-carriers, all machined from solid Anticordal billet. This results in a 1435mm wheelbase, and is actually stiffer as well as lighter than the DB7's steel-framed structure, says Acquaviva.
The first prototype Oronero-Italian for "black gold"-was completed in September 2008, and after initial testing proved encouraging, the decision was taken to launch a customer version at the 2008 EICMA Milan Show. "Really, only Bimota could produce such a bike for the street, because all our products are hand-built anyway, and a carbon fiber chassis can't be built on an assembly line," says Acquaviva. "Still, we were really surprised, and gratified, that we got so many orders for the bike after EICMA. It showed that our customers appreciated what we were trying to do."