As the RSV4 project gathered momentum, the RSA250 two-stroke served as an electronic testbed for the forthcoming Superbike. "The RSV4 was still too green to perform this role, so we used the 250 as a dynamic prototype to develop our traction control program," said Dall'Igna. "We used TC on the RSA250 since the third race of 2008, and after three or four races we had it working very well. Then, in September 2008 we transferred the entire package to the RSV4, and began adjusting it to the slightly different demands of the V4 four-stroke engine. We saved time and learned a lot doing that. One reason Simoncelli adapted so quickly to the Superbike was because he was already used to this!"
Another reason was most likely because the RSV4 is as compact and easy to change direction on as a 600 Supersport, flicking from side to side far quicker and more easily than the Ducati. And that's in spite of the rangy 56.7-57.0-inch wheelbase Max opts for in the interests of front-end grip. It has incredibly responsive steering, and coupled with that explosive power delivery, this makes it quite a difficult bike to ride, one that requires heaps of commitment and concentration from its rider. Biaggi's preferred chassis setup on the Aprilia is extreme compared to the much more balanced format of, say, the Haga Ducati or Corser BMW, reflecting Max's GP pedigree. The result feels tall and ungainly at slower speeds, until it all starts to come together once the pace picks up; but the chassis is so stiff you can feel every small imperfection in the road surface, even on a smooth track like Mugello. That's in spite of the fork settings being quite soft, which with my extra weight compared to Max's increased the weight transfer under braking, and loaded up the front tire even more. But the Ohlins TTX fork still kept working while leaned over, even when trailbraking into an apex, and didn't bottom out under my extra kilos. One thing I could have done without were the slippery footrests, though; my boots kept sliding off them.
It's easy to see why there...
It's easy to see why there has been some grumbling about the Aprilia's "production" parts that display a lot of handbuilt origins. The CNC-machined engine sidecase and sandcast-looking cases show a lot of craftsmanship. Note the position of the adjustable swingarm pivot.
The Öhlins TTX36 rear shock...
The Öhlins TTX36 rear shock sits nestled in a densely-packed cavity in the swingarm. Note the protective heat shield over the datalogging sensor, due to its proximity to the rear cylinder bank of exhausts.
The Aprilia RSV4 Superbike...
The Aprilia RSV4 Superbike front end is graced with an '09 Öhlins FGR900 TTX20 gas-pressurized inverted fork attached to the newest Brembo 2-pad/four-piston monobloc calipers gripping 320mm discs. A 3.50 x 16.5-inch Marchesini forged magnesium wheel is shod with Pirelli's latest Diablo Superbike 120/75R420 rubber.
The Aprilia chassis does a top job, with plenty of ground clearance thanks to the compact engine, and an ease of steering that is truly addictive. Because the race-pattern gearchange entails fitting a linkage, the shift action was much more precise than the streetbike's direct setup that was difficult to make a clean upshift. I never used the clutch when shifting gear in either direction on the RSV4; the combination of the ECU's variable idle-speed program and the mechanical slipper clutch worked ideally together when braking aggressively for corners.
Aprilia has spent the '09 season preparing for a full-on attack on the World Superbike Championship in 2010. The RSV4 is by far the most refined and potent Superbike I've yet ridden, and it has to be the favorite for the title in the coming season. Because it combines so many of the characteristics of a twin as well as a four, the Aprilia RSV4 may well be that rare thing on two wheels: the best of all possible worlds. Let's see if Max Biaggi-or new signing Leon Camier, who dominated the '09 British Superbike Championship-can reward Aprilia's clever engineers headed by Dall'Igna with the World Superbike title in 2010. They deserve it for creating this great bike.