2007 Aprilia RXV 450 & 550 Dirt Bikes - First Ride - Dirt Rider Magazine

With a Red Bull in hand, I am writing this high over the clouds. Most of all, I'd like to sleep, but I can't shake the hard-hitting Aprilia RXV 550 out of my mind. The RXV 4.5 and 5.5 launch was at Riserva Naturale Pino d'Aleppo in the middle of rural Sicily. I guess Aprilia made the landowner an offer he couldn't refuse, as he sacrificed his field to the roaring RXVs.Luckily, I rode the RXV 450 first on enduro terrain. Both bikes come standard with Michelin Enduro Comp III tires. Believe me: You need every bit of grip you can get, especially on the RXV 550. We also rode the two RXVs on a grass track, where there aren't many bikes that will beat the 450. Who would have imagined a highly competitive off-road 450cc V-twin only a few years ago? V-twins are for touring and adventure enduros, not for off-road racing. But make no mistake-this is a race bike. The RXV 450 is a serious challenge for Honda's CRF450X and KTM's 450 EXC, particularly since the Italian puts its massive horsepower down better than the singles. But with the AMA banning twin-cylinder race bikes in pro racing, the bike's immediate future is somewhat cloudy.RXV 450 is all about loads of usable power. The 77-degree V puts out around 55 bhp in a much smoother, more tractable way than a single. When I first started the engine, it was evident this off-road machine is very powerful (it sounds rowdy, too). Even with all the horsepower, that rear tire digs in and the bike surges forward. Power is spread over a very broad range, and there's plenty of overrev. You quickly develop biceps like Popeye's riding this bike. Compared to a single, you have much more power to play with anywhere in the powerband but with less engine-braking. That puts more importance on braking and riding style in corners. Seat height is a tall 39.2 inches to allow plenty of ground clearance and wheel travel. The V-twin engine allows for an even slimmer frame than a 450cc single. Balance is superb; it is something the twin engine lends itself to naturally. Despite the fact that Aprilia claims the engine tips the scale at no more than a single, the RXV weighs more than high-end singles. A claimed dry weight of less than 220 pounds is not unusual on singles; the RXV 4.5 claims 258 pounds. The actual weight of a KTM 450 is about 255 pounds ready-to-ride with an empty tank, so if Aprilia is accurately reporting the bike's weight, the twin isn't overly porky. Titanium valves and magnesium covers help to keep the weight of the engine down, but we suspect the complex chassis and exhaust system add weight compared with a single. However, the balanced package and power delivery compensate for the extra weight. Our riding did not involve any big challenges, so it is hard to tell how the extra weight would have affected us on tougher terrain.The suspension was perfect for gravel roads with small stones-soft enough to absorb small hits but still firm enough for high speeds. The standard setup is ideal for light enduro riding, in other words. For jumps and hitting big rocks or crests at speed, the fork springs are a bit on the soft side. There is very little sag, but the rear shock squats under power. The rear suspension is a single shock sitting on a gorgeous aluminum swingarm. The shock also has high/low-speed compression settings. The front suspension is a 45mm USD adjustable fork. The SXV supermoto models got a differently calibrated 48mm USD fork and a wider swingarm to fit wider wheels. This makes it difficult to convert an RXV for supermoto. Gearing is different to suit the diverse riding styles. All of the XVs are very single-minded and made for racing. The adjustable fat handlebar and Domino grips are nice but are placed too far back for my liking. Too often I felt as if I was hanging by my arms rather than achieving full control. (This was particularly noticeable on the powerful RXV 550.) On the grass track, I could easily point the front where I wanted to go without using too much muscle and still be able to keep the throttle open. The RXV 450 grips better than most bikes out of bends-you can really go for it. The RXV 450 blew me away, and I was truly worried when it was time for the 550.RXV 550: The BeastNeither the 450 nor 550 are friendly enough for easygoing trail riding. Suspension, chassis and wheels are the same as on the 450. For the enduro part, I found it difficult to stand up for any long periods on the 550. The power is so on-off and there is so much of it that I spent more time trying to tame the beast than actually testing it. Hard-hitting is the word. Even when short-shifted, that monster torque curve punishes the rear tire. As soon as I tried to do anything but baby the gas, the rear wheel spun. With its current engine mapping, the RXV 550 is a violent, powerful beast of an enduro motorcycle. Aprilia has several engine maps for the 550, but this one offered too much torque too early in the powerband. It is a fortunate thing the brakes are good. I instantly felt that I would not have enough time on this short test (the SXV supermotos were waiting for us at the go-cart track on the other side of the island) to get much out of the 550. The 550 wore me down so quickly, I decided to sit it out until I could get back on the 450 for the photo sessions. In reality, I would have needed at least a full day on the biggest RXV to get the most out of the power. The 550 simply has too much power for the riding that we did. It is the most demanding of Aprilia's XVs to ride and should only be recommended to expert enduro riders.The exhaust system, which is barely visible under the rear mudguard, is a true work of art. The angled and slashed pipes blend in to a very exciting design. Attention to detail is truly great. There is just as much thought put into the overall design and finish as into the 77-degree V engine. Both RXVs come with a 2.0-gallon fuel tank, but there will be a 3.2-gallon version available in certain markets.ConclusionThe $8199 RXV 450 was blindingly fast on the gravel and dirt. It has the perfect combination of tractability and speed. It could easily be flicked from side to side on the grass track. The RXV 550 (price TBD) is just too much to handle and requires loads of skill from the rider. It could be the expert's choice, but even an expert can't do too much magic with the rear wheel spinning all the time. Different engine mapping could solve the problem. The 450 has the best of both worlds, since it is smoother and seems more powerful than any other 450. It was easier to control the power delivery, and it flew around the grass track. The RXV 450 is ready to race and even a average rider could start challenging 450 singles on the track. Aprilia has a habit of making things right the first time. Considering that the company has engineered the new engines and chassis to enter the unknown off-road market, it's a big thumbs-up to Noale. Bravissimo.RXV 45O
What's Hot

Engine tuned for tractability
Handling
The most stylish off-road bike since KTM

What's Not
You are paying for style you don't really need off-road
Suspension on the soft side

RXV 55O
What's Hot

The most stylish off-road bike since KTM
Serious speed for open roads

What's Not
Spins up everywhere
Only for specialists

\"You quickly develop biceps like Popeye\'s riding this bike\".
\"Even when short-shifted, that monster torque curve punishes the rear tire\".
\"You quickly develop biceps like Popeye\'s riding this bike\".