The Aprilia's instrument panel...
The Aprilia's instrument panel is simple and nicely laid out, with an analog tachometer centrally placed above the LCD panel, although the mirrors aren't very functional.
The same raving by everyone who rode the Aprilia on the street occurred at the track. It was interesting to watch practically every rider step off the RSV4 Factory, look back at the bike, and then begin babbling to everyone how much fun it was to ride.
It's easy to see why. The same agility and composure the chassis demonstrated on the street was duplicated on the racetrack - only magnified tenfold due to the increase in pavement it could play with and the increased speeds. That poise in any cornering situation fosters gobs of rider confidence, aided by the smooth and strong V-four engine that supplies easily manageable yet stout acceleration. It certainly isn't the strongest of the bikes in this group, but the Aprilia's lithe handling allows the powerplant to generate speed in cornering situations and areas of the racetrack where the others would find it difficult. The difference in performance between the standard R and Factory engines may not be huge, but the impact of the Factory's smoother powerband on its ability to exploit that power is unmistakable.
The Öhlins suspension components play their own role as well. While the Showa pieces on the standard R models are far from subpar, the increased competence of the Öhlins fork and shock when the pace is really ramped up contributes to the Factory's unflappable handling. The lighter forged aluminum wheels surely play a role here as well.
The Brembo monobloc calipers and 320mm discs provide excellent stopping power, although they definitely weren't the top-rated brakes in the test. Some testers complained of slight fading during hard use, while others wished for a little more feel at the limit. But these were minor blemishes on what ended up being glowing reviews on nearly every evaluation sheet.
Racepak G2X Data Analysis
For each of Kent's sessions at Buttonwillow, we mounted our Racepak GPS-based data acquisition system on the passenger seat to keep tabs on his and the bike's progress. In our Bike Meets Car story (Aug. '10) we introduced the lap-time difference channel, which gives us the gap in time between the bikes at any point on the racetrack. In that story, we plotted the channel along with the speed traces. Here, the speed traces versus distance for each bike are plotted on the traditional graph but we used the lap-time difference data to show the relative positions of the bikes on the track at several points. Additionally, the segment times for each bike in each corner are shown on the track map.
Lap Times
Aprilia: 1:09.194
BMW: 1:09.765
Ducati: 1:09.718
Kawasaki: 1:09.943
MV Agusta: 1.09.428
Considering the disparity of equipment in this test, from the Kawasaki ZX-6R to the almost twice as expensive Aprilia RSV4 Factory, the lap times are remarkably close. Less than a second covers the five bikes, with the Aprilia leading the way by more than a quarter-second. Unfortunately, the surface at Buttonwillow has deteriorated significantly since our last test at that track in 2009, and the times are correspondingly slower.
From the speed data, it's clear the bikes are quite evenly matched over the course of the lap. Each straight section shows the Kawasaki at a clear disadvantage to the other bikes, while the BMW shows moderate gains. Over the first half of the lap, it's almost a draw between the five contenders. Because we use only the West Loop at Buttonwillow, the first turn doesn't see much activity and is usually quite slippery. Here, the BMW immediately opens up a gap on the other bikes, perhaps thanks to its traction control system. In the all-important fast and bumpy Riverside turns (sections 2 and 3), the MV Agusta is quickest while the slowest Aprilia loses just a quarter-second in segment time. The BMW actually leads the way through the first half of the lap, with the Kawasaki and Ducati trailing.
The field bunches up on the run up to Turn 4, with the BMW losing a chunk of time under braking and just .16 seconds separating the five bikes at the entrance of the turn. With its apex at the crest of the hill, this turn rewards front-end feel, and here the Aprilia and its confident chassis starts to draw out an advantage with a sector time more than .1 seconds quicker than the next fastest bike, the Ducati. The next segments sort things out significantly. The relatively underpowered Kawasaki loses time on the run down the hill, but both it and the Aprilia scythe through the Riverside turn much quicker than the other bikes. The segment times show the Aprilia and Kawasaki .3 seconds faster than the MV Agusta and BMW, and almost a half-second quicker than the Ducati in this turn. Here is where the Aprilia makes a large part of its lap-time advantage on the BMW, Ducati and MV Agusta.
Surprisingly, the lightweight and quick-steering Kawasaki cards the slowest segment time through the Chicane while the BMW makes it through marginally quickest. The Kawasaki may have made it through the previous turn plenty fast enough, but the big bikes have more entry speed and gain more on the exit, making up time overall. The next straight, between the Chicane and the final turn, sees the maximum speeds for the lap; here the BMW shows its power advantage, but the MV Agusta is less than 1 mph behind while the Kawasaki lags by almost 10 mph.
The final turn, a moderately tight, 90-degree bend, may seem simple enough but actually decides the BMW's fate in overall lap time. Heading into the turn, the BMW is behind only the Aprilia according to the lap-time difference channel, but falls behind the MV Agusta and the Ducati through the turn. Just as on the run up to Turn 4, the BMW loses out under hard braking; here, however, there is not enough of a straight following for it to make up the difference. The BMW's ABS system is the probable culprit here; although it works extremely well in Slick mode with a very high threshold before intervention (and when it does intervene, it does so very transparently), the BMW builds up so much speed down the straight that the braking effort is high enough to cause ABS actuation, causing a loss of braking power compared to the others.