BMW caused a few arguments at last September's Intermot show in Munich when it pulled the wraps off a concept bike based on the R1150R roadster. With lurid paintwork and graphics, asymmetrical headlights from the dual-purpose R1150GS and a bunch of cycle parts borrowed from elsewhere in the boxer range, the prototype generated plenty of strong comments.
Enough people liked the bike for BMW's bean-counters to decide that the sums added up. Six months later the R1150R Rockster entered production to add a bit of edge to the boxer range. BMW's standard R1150R was often described as the firm's bad attitude bike following its launch two years ago, but the Rockster's squint-eyed stare gives it a notably meaner look.
Along with the distinctive bodywork shapes inherited from the 1150R, this bike's orange and black paint scheme is an equally vivid alternative to the original lime green and black (which is an option). Above the headlamps is a small wind deflector that houses an instrument panel which, in suitably idiosyncratic fashion, combines a black-faced speedo and white tach.
Most of the Rockster's components, including its 1130cc, eight-valve air-cooled engine come from the R1150R. This is the first of BMW's boxer motors to be fitted with the new twin-spark cylinder heads that will be introduced throughout the range this year. They're claimed to reduce fuel consumption and emissions by giving more uniform combustion, but the motor's performance, including its peak power output of 85bhp at 6750rpm, is unchanged.
Chassis bits are also borrowed mostly from the R-bike, including the tubular steel space-frame with its Telelever front and single-sided rear suspension systems. Some parts are from the sportier R1100S, though, including the smaller front mudguard, the Telelever stanchions and the wider, 5.5-inch rear wheel, which wears a 180/55-section Michelin Pilot Sport in place of the standard model's 170.
Ergonomics are slightly altered by the Rockster's flatter handlebars and a seat which at 835mm, is 35mm taller than the R's. (A 40mm lower seat is available as an option.) At 219kg dry the BMW is not particularly light by naked bike standards, either, but its generous steering lock was helpful in traffic. And when the lights changed the Rockster stomped forward pretty rapidly. It pulled cleanly from below 2000rpm, with a flat note from its twin pipes, working best in the midrange zone between about three and five grand.
From that point up the motor got a bit buzzy, and stayed that way until the redline at 7500rpm. But five grand in top is an indicated 90mph, so the Rockster was pleasantly smooth at a typical almost-legal freeway pace, with power in hand for brief bursts towards a top speed of about 120mph. By naked bike standards it's well suited to reasonably rapid cruising, too, as the flat bars and fairly rearset pegs give a roomy riding position with a comfortable lean forward into the breeze.
Typical BMW touches include a generously sized seat for both rider and pillion (shame there's no grabrail), and optional heated grips. On longer trips you're more likely to be annoyed by the motor's thirst, which has traditionally limited the R-bike's 5.3-gallon tank's range to less than 200 miles. Maybe the twin-plug heads will help fuel consumption slightly.
If the Rockster's straight-line performance was respectable without being razor sharp, then much the same was true of a chassis that gave the bike a very stable feel, plus enough agility to make for some fun in the bends. Much credit for that goes to the Telelever front end, which was a bit harsh on the wrists at slow speeds, but whose lack of brake dive made for solid and precise handling.
The single-shock rear end worked well, too, giving a fairly firm ride and soaking up most bumps effortlessly despite the weight of the drive-shaft assembly. Cornering clearance was good enough that only the footrests touched down even when the bike was cranked over far enough to make the Pilot Sport tires work hard. There's a hydraulic remote preload adjuster, as well as adjustment for rebound damping.
The EVO brake system delivered its impressive blend of servo-assisted stopping power from the front blend of 320mm discs and four-piston calipers, too, with the occasional help of the optional ABS system to calm the sharp rear. Most other details were present, correct and typically BMW, including the small but useful mirrors, traditional annoying switchgear, and what promises to be an excellent level of finish. One thing that's hardly a BMW trait is that the Rockster is priced very competitively. An eccentric naked bike like this is not for everyone, but don't be misled by the styling. It's a bit of a upper class punk rocker, this Rockster is built for people who are attracted to a nasty image, yet deep down really want something polite and refined. If that's what turns you on, the Rockster will not disappoint.
BMW R1150R Rockster Specifications
Engine type: Air-cooled boxer
Valve arrangement: high cam, 8 valves
Bore x stroke: 101 x 70.5mm
Compression ratio: 10.3:1
Carburetion: Motronic fuel-injection
Maximum power: 85bhp @ 6750rpm
Maximum torque: 73lb.ft @ 5250rpm
Clutch: Dry single plate
Front suspension: Telelever single shock, 120mm spring travel, adjustment for rebound damping
Rear suspension: One damper, 135mm spring travel, remote adjustment for preload and rebound damping
Front brake: 2, four-piston Brembo calipers, 320mm discs, EVO servo system, ABS option
Rear brake: Twin-piston Brembo caliper, 276mm disc
Front wheel: 3.50 x 17in; cast aluminium
Rear wheel: 5.50 x 17in; cast aluminium
Front tyre: 120/70 x 17in Michelin Pilot Sport
Rear tyre: 180/55 x 17in Michelin Pilot Sport
Seat height: 835mm
Fuel capacity: 20.5 litres
Weight: 219kg dry
Instruments: Speedometer, tachometer, digital clock, lights for brake system, injection, indicators, neutral, high beam, charging system, oil pressure, low fuel