Aprilia’s approachable take on the middleweight supersport segment

By Michael Gilbert, www.cycleworld.com

The RS 660 is the child of Aprilia’s open-class superbike technical expertise combined with everyday functionality and comfort, making it an enticing option to the supersport-curious. Yet it’s wickedly entertaining and capable of educating even the most experienced riders. Think scaled-down RSV4 1100 Factory performance in an approachable package. It’s a fresh and unique take on the middleweight supersport segment. And it’s freakin’ awesome.

As extensively covered by CW Technical Editor Kevin Cameron, Aprilia has taken a contemporary approach to the middleweight class, forgoing the competition-inspired path of the high-revving Japanese inline-four machines that have traditionally ruled the roost. Aprilia recognized that these models have become too specialized for the average consumer, too uncomfortable for more than a few miles, and too expensive. The RS 660 was created to address these issues.

Powering the solution is a 659cc DOHC parallel-twin engine which recorded an impressive 88.81 peak horsepower at 10,450 rpm and 45.34 pound-feet of torque at 8,530 rpm on our in-house Dynojet 250i. Equally impressive is the 660′s broad, flat torque curve, which really graphs out more like a tabletop; its linear power delivery makes for a very tractable, friendly ride. That said, the usual mass of superbike horsepower isn’t there to fall back on if you aren’t on the ball. Extracting the potential of the RS 660 means carrying momentum and linking curves together, which is the most fun and instructive aspect of riding it. Still, when wicked up the Aprilia is a middleweight missile.

It’s a hoot on the backroads. Roll on the throttle and the 660 produces immediate, usable power from 6,000 rpm, letting you pull strongly from the corner exit and gaining real life at the 8,000 rpm mark. There the 660 lets loose with an evocative exhaust howl and accelerates vigorously to its 11,500 rpm redline. Keep it spinning and you’re rewarded with a seriously good time.

As much of a ripper as the RS 660′s powerplant is, it has balance that any rider, new or seasoned, can appreciate. Extra low-end grunt separates it from the inline-four screamers and adds around-town everyday flexibility to the machine. Throttle response from the ride-by-wire system is crisp, and the excellent connection to the rear wheel boosts rider confidence even in the most aggressive of three selectable ride modes. It’s delightfully smooth at highway speeds, settling in around 6,000 rpm in top gear and letting the rider enjoy the cruise control function, interrupted only by the somewhat annoying buzzy mirrors. A combined 42.4 mpg aids peace of mind. And when it comes to the canyons, the factory-equipped up/down quickshifter promotes smooth, almost seamless progress through the six-speed gearbox, helping with tightly spaced gear ratios that demand numerous changes on a spirited run.

Aprilia’s technical aptitude is on full display with the RS 660; the superbike-level Aprilia Performance Ride Control (APRC) electronic rider aid package squeezes out every ounce of performance. A trio of factory ride modes, Commute, Dynamic, and Challenge, offer fixed levels of traction control, wheelie control, engine-brake management, and ABS settings, adding to the 660′s versatility. Two additional modes, Dynamic and Time Attack, offer customizable options for the eight-level traction control and three-level throttle response and wheelie control settings. Land on level 2 of traction control with wheelie control off and the Aprilia blends seamless electronic intervention with tractable power delivery for ruthless-yet-manageable corner-exit speed. It’s polished electronic interference, mitigating rear-wheel slip to reduce risk without sacrificing any of the RS 660′s personality. The best of all worlds. Really.

Ergonomically, the RS 660 is a similar story. The raised position of the clip-on style handlebars and somewhat relaxed footpeg position add to the middleweight’s utility without the overly aggressive stance and uncomfortable position of traditional supersport models. Comfortably rocking hundreds of miles or daily commuting in comfort is no question. A 32.2-inch seat height and narrow saddle width lends itself to easy low-speed maneuvers and will doubtless help the bike feel approachable to smaller or newer riders. Still, the rider triangle is sporty enough to quickly hustle the 660 without dragging controls.

And the RS 660 enjoys ripping a technical sequence of corners. Handling is sharp and agile, providing quick cornering at maximum lean. It quickly snaps through side-to-side transitions with little effort, yet remains composed and stable at speed. It’s an any-apex-anytime attitude on this Aprilia. If there’s any gripe in the RS 660′s handling, it comes in the form of its rebound damping and spring preload adjustable-only KYB suspension. The initial stroke of the fork is harsh and lacks small-bump compliance, ultimately robbing confidence and feel on imperfect tarmac. Compression damping adjustability would be welcomed. Certainly the suspension isn’t overburdened. At a measured 401 pounds with its 4.0-gallon fuel tank topped off, the Aprilia is relatively lightweight for the middleweight class; for reference, the last Kawasaki ZX-6R we tested weighed 432 pounds.

The Aprilia is impressive at corner entry, though an overaggressive initial brake bite tends to hinder its potential. Squeeze the lever tightly while in a rush to slow the 660′s speed, and you may find the power of the Brembo Monoblock calipers difficult to modulate. It’s a problem that hurts the overall feel when traveling at a spirited pace and is especially noticeable in the tight confines of urban riding. Aprilia’s three-level engine-brake control helps out here though, adding adjustability of deceleration and ensuring confidence at the tire’s contact patch in braking zones.

Having spent countless miles on inline-four 600cc middleweights, I can say that the Aprilia RS 660 is an attractive addition to the category. It balances an engaging supersport punch with a more practical approach for a wicked good time on two wheels, commute or canyon twisties alike. The blend gets my vote for all manufacturers to follow.

Gearbox

Helmet: Arai Corsair-X

Jacket: Alpinestars Newman Overshirt

Pants: Alpinestars Victory Denim

Boots: Alpinestars Faster-3 Rideknit

2021 Aprilia RS 660 SPECS

Engine:	659cc, DOHC, liquid-cooled parallel twin; 4 valves/cyl.
Bore x Stroke:	81.0 x 63.9mm
Transmission/Final Drive:	6-speed/chain
Cycle World Measured Horsepower:	88.81 hp @ 10,450 rpm
Cycle World Measured Torque:	45.34 lb.-ft. @ 8,530 rpm
Fuel System:	Fuel injection w/ 48mm throttle bodies
Clutch:	Wet, multiplate
Frame:	Double-beam aluminum frame
Front Suspension:	41mm KYB inverted fork, spring preload and rebound damping adjustable; 4.7 in. travel
Rear Suspension:	KYB monoshock, spring preload and rebound damping adjustable; 5.1 in. travel
Front Brake:	Brembo radial-mount 4-piston-calipers, 320mm discs w/ cornering ABS
Rear Brake:	1-piston caliper, 220mm disc
Wheels, Front/Rear:	Aluminum alloy; 17 x 3.5 in. / 17 x 5.5 in.
Tires, Front/Rear:	Pirelli Diablo Rosso Corsa II; 120/70-17 / 180/55-17
Rake/Trail:	24.1°/4.1 in.
Wheelbase:	53.9 in.
Seat Height:	32.2 in.
Fuel Capacity:	4.0 gal.
Cycle World Measured Wet Weight:	401 lb.
Availability:	Now
Contact:	aprilia.com