MotoGP performance for the real world
The V4 engine is a stressed member of the chassis, which is based on a steel-trellis frame in best Ducati tradition. Rake can be altered between 23.5 and 24.5 degrees using the eccentric steering head, as on the 916, while wheelbase measures 56.3 inches (identical to that of the 1098, but longer than the GP6) to aid stability under acceleration. The rear subframe is a self-supporting carbon-fiber structure that Ducati claims is a first for a production streetbike, though Bimota's SB6 featured a similar construction 15 years ago. What is not in any doubt is the RR frame's extraordinary rigidity: Weighing less than 16 pounds, it's 20 percent lighter and 80 percent stiffer torsionally than its 1098 equivalent. The D16RR's aluminum swingarm is also hugely rigid, weighing 10 percent more than its twin-sided equivalent from the 999 but providing 35 percent more torsional stiffness. Overall the RR frame is much closer to that of the MotoGP bike than to any other roadster.
Wheels are ultra-light forged-magnesium six-spokers from Marchesini, the rear an enormous, MotoGP-spec 6.25-incher. At less than 6 pounds front and 9 pounds rear, they're significantly lighter than the 999R's forged-aluminum hoops. Bridgestone developed special BT-01 rubber for the D16RR, featuring a super-soft compound and taller sidewalls. The Japanese firm intended to follow MotoGP fashion with 16.5-inch tires, but was prevented from doing so by U.S. tire-industry regulations, so settled on a conventional 17-inch front and a 200mm-wide, 16-inch rear-both livened up by a tricolore stripe of red, white and green in the center of the minimalist tread.
Although the day when carbon-fiber brake discs will be used by high-end streetbikes is probably not far away, poor wet-weather performance currently prevents the composite material from being used. The RR does, however, use carbon fiber for its bodywork, including all fairing parts, the airbox and air ducts, the front fender and most of the tailpiece. Dry weight is 376 pounds-40 pounds up on the GP6 racer and 4 pounds lighter than the 1098.
The Desmosedici RR has by far the most sophisticated suspension yet seen on a Ducati, or any other streetbike for that matter. Its 43mm hlins fork is the world's first on a production streetbike to feature pressurized damping, courtesy of the remote reservoirs at the bottom of each leg. They are adjustable for high- and low-speed compression damping, as well as for spring preload and rebound damping, and standard settings reflect what is currently being used in MotoGP. The Swedish firm also provides the shock, which sits vertically below the swingarm, with its lower mount connected to the engine via a forged-aluminum plate. Riders in search of the perfect rear-end set-up can choose from 20 settings for low-speed compression damping, 48 for high-speed and 25 for rebound damping, as well as fine-tuning the preload and ride height. There's also an adjustable hlins steering damper, mounted below the left clip-on in traditional style.
The brake system is unique in that the D16RR is the first streetbike to feature a race-style remote adjuster for its radial master cylinder; a tube running to a knob near the left clip-on lets the rider adjust lever span on the fly. The front stoppers are the same Brembo blend of 330mm discs and radial Monobloc calipers used on the 1098. Both front brake and clutch controls incorporate "supple levers" that are designed to hinge under the force of a crash, increasing the likelihood of the bike remaining rideable.
Ducati's first production four-cylinder churns out a mind-boggling 188 bhp.
Like last season's GP6 racer, the Desmosedici RR is powered by a 90-degree V4 with bore and stroke figures of 86.0 x 42.6mm, yielding 990cc. Unlike the current 800cc GP7 racer, it shares the 990's twin-pulse firing order with crankshaft throws spaced 70 degrees apart, giving an irregular 0, 90, 290, 380-degree firing sequence. Although most components have been redesigned for street use, the general architecture, including the desmodromic valvetrain, is similar to that of the racebike. The cams are gear-driven, the rocker arms have a precision-ground finish to reduce friction and the crankshaft is machined from a single lump of forged steel, while the bottom end incorporates a six-speed cassette transmission and slipper clutch. Lightweight titanium is used for valves and connecting rods, the crankcase and cylinder heads are sand-cast aluminum and the engine covers are magnesium-a mixture of sand-cast for the structural cam-drive cover and alternator case, and pressure die-cast for the non-structural oil sump, cam and clutch covers. Fuel injection comes courtesy of four Magneti Marelli 50mm throttle bodies featuring 12-hole injectors, while the exhaust is a 4-2-1 system that sees a pipe run down through a large slot in the aluminum swingarm and then back up again before reaching the catalytic converter and under-seat muffler. Replacing the stock silencer with the race kit alternative saves 10 pounds and adds 12 horsepower, boosting peak output from 188 bhp at 13,800 rpm to 200.