Text: Sandeep Goswami/Old Fox
Photos: Sandeep Goswami & Sunil Gupta
Did you know that at times a motorcycle tyre can talk to you? That it can give a running commentary of all that’s going on beneath its contact patch. Ever experienced practical lessons in the physics of friction and traction from your bike, live and as you ride? Go ride the BMW K1300S if you haven’t experienced anything like that till now and want to. This bike has the most communicative front end of any bike that I have ever ridden, big, medium or small in size, weight or performance. The front suspension is just….ah! well, all in good time. Let’s be a little systematic with the review, build a preamble of sorts about the bike first and not jump the gun in enthusiasm.
The K-1300 is an evolution of the previous K 1200 series from BMW. The 1200 was in its time the most powerful offering from the Blue Propeller but was beset with some niggling issues that possibly contributed to its not really catching the fancy of the discerning motorcyclist. Intermittent fueling, jagged off and on-throttle response, a clunky gearbox and a slight high-speed instability were the major grouses that needed rectification. BMW Motorrad went about evolving the 1200 into a new model not just by solving those issues but by virtually building a new motorcycle altogether in the K 1300 series. The K1300S is the fully-faired hyper-tourer that we are reviewing here. The ‘R’ is the naked version with essentially the same hardware but some tweaking to give it a different and more aggressive character. And of course it is ‘naked’.
The engine of the K1300S is a 1293cc unit, an increase in capacity by 136cc over the base 1200 one, achieved by increasing the bore by 1mm and stroke by 5.3mm and the power has been upped by some 8 bhp with a proportionate increase in torque. The transverse 4 cylinder in-line engine is inclined at 55 deg forward and is as long legged in feel and performance as they come. This is a blisteringly fast bike, no second opinions about that. Sub 4 sec 0-100 kph timings stand testimony to that. The new engine however gives a far wider and smoother torque and power spread which allows the rider to slot in sixth and then just roll that throttle to swoosh past other traffic.
The bike is big and imposing to look at though nicely proportioned. Looks sleeker, slimmer and slicker than the Hayabusa. With a wheelbase of 1585 mm and measuring a little more than 2 meters in length (2182 mm in fact), it is a lot of motorcycle between the wheels. And weighing in at 254 kg fully fuelled, it isn’t light either. But get it rolling and feel the length and weight shrink into controllable dimensions pronto. The front fairing is big, dominated by that single casing dual bulb headlight that has a ‘candle-stand’ parking light inside. The stalk-mounted RVM’s look delicate but are robust enough to withstand wind blasts of 300 kph that the bike is capable of! The tail looks a trifle anemic but then the taper proportion is possibly dictated more by the demands of aerodynamic streamlining than sheer aesthetics. The moulded ‘contoured’ seat looks expansive and comfy. The single-sided swing-arm with that famous Paralever shaft drive is a visual treat for the technical minded.
Insert the key and turn it clockwise to switch on the electrical and ignition. The console lights up orange and the rectangular LCD display on the right (beside the white-dialed analog speedometer and the smaller tachometer to its left) shows basic info in default – clock, odometer reading, ABS available, fuel level and engine temperature as vertical strip indications and gear position. There’s an ‘info’ button on the left handlebar cluster using which you can toggle through a variety of info menu’s on the same LCD.
The red engine kill switch on the right also doubles as the starter switch. The engine will not start if the bike is in gear and the side-stand is down. Push the starter and after a longish whirr, the engine comes to life with a muted growl. Sounds delicious even at idling. Settling to a sub-1000 rpm idle, the warm up time is short in Delhi’s hot summer and within less than a minute we are ready to roll. Blipping the throttle reveals an engine very eager to be revved and promises good fun on the move. Pull in the heavy but smooth hydraulically actuated clutch and slot the bike into 1st gear. A solid ‘thunk’ announces you have some 170+ bhp tugging at the rear wheel at the drop of that clutch now. Gently roll the throttle as you release the clutch and you’re moving. The front end that seemed unusually heavy while the bike was parked becomes progressively light and starts sending back a clear stream of contact info from the front tyre. The blinking red ‘ABS-engaged’ indication next to the gear position indication on the LCD goes off once you get rolling. Shifting through the firmly shifting but slightly clunky gearbox has the bike pulling effortlessly and smoothly across the rpm band, with an aggressive change in the engine note and behavior past the 4000 rpm mark. Vibrations are next to nil till about 7000 rpm whereon they are mild right to the redline.
Power to be safe and effective needs control and that’s where the handling and braking prowess of the bike comes to the fore. The BMW patented Duolever front suspension was introduced in the 1200 series earlier as the Telelever system and does business in the 1300 in a slightly new avatar. This makes the bike’s feel and response to steering inputs quite different from what we are used to with conventional telescopic forks. In tandem with the Paralever system doing duty at the rear end, this gives the bike exceptional handling behavior. Read about this novel suspension in detail below.
BMW DUOLEVER EXPLAINED
The telescopic front fork has dominated motorcycle front suspension design for decades now and the improvements brought about by USD forks have further strengthened its stranglehold. But this dominance does not mean there are no other options and also that those other options are inferior by default. The telescopic front suspension, for all its apparent simplicity, ease of production and familiarity is weighted down by an inherent drawback. Since the telescopic fork handles the combined forces of steering and suspension through common physical components, both of these are directly transmitted to the rider through the handlebars/clip-ons. Though interestingly, this drawback is considered a distinct advantage by some who take these forces as feedback information. Whether the rider necessarily needs feedback of such magnitude is the debate. In addition, the telescopic fork induces dive on braking and is also weak in torsional stiffness. To understand torsion, grab hold of the front wheel and try to twist it while keeping the handlebars straight and rigid. Though no noticeable twist occurs when you apply force by hand but the tubes tend to twist relatively easily during cornering at speed and especially on rough surfaced turns. Something which is not at all desirable from a control point of view.
The Duolever front suspension on the K1300 series is an evolution of the Telelever system from the K1200 which in turn is based on the principle design by Norman Hossack, a British engineer who once worked on McLaren race cars and later moved into motorcycle suspension design. The Duolever suspension in principle separates the braking/suspension forces from the steering forces. There are separate and discreet components to handle suspension duties and steering. This means that the rider only controls and feels the steering inputs while the suspension forces are transmitted directly to the motorcycle chassis. So steering the bike becomes easier and more precise. But more importantly, the struts for mounting the front wheel can thus be made as stiff and rigid as desired and so torsional stiffness is vastly improved. This results in far superior steering accuracy and directional stability than is possible with the telescopic fork.
Ironically, the basic design comes from cars vis a vis the way the front wheels are suspended in a car. The Duolever system uses two ‘wishbones’ mounted one above the other. ‘Wishbones’ are triangular components with mounting holes at all three vertices. The ‘double wishbone’ arrangement has the base of both connected to the bike frame and the apex of the triangles connected to the wheel mounting struts (the wheel struts are a visual parallel to the twin forks but rigid in construction). A shock-absorber/damper unit connects the wheel strut head (which moves up and down as the wheel encounters road undulations) with the frame of the bike. A steering head located on the bike frame right above the double wishbone set-up links the handlebars with the wheel struts through a hinged linkage. This linkage is just there to help steer the bike and has no role to play in handling suspension forces. So the wheel is steered independent of the up-down suspension travel.
From a rider’s point of view, the Duolever feels quite different compared to the telescopic fork.
• There is no noticeable front end dive under hard braking. So the rider would be decelerating a lot quicker than he would realize since he’s used to gauging the severity of braking though the front end dive. The excellent ABS here helps a big deal as it avoids the nasty consequences of inadvertent and dangerous over-braking as the lack of ‘dive’ feedback can make the rider brake beyond the limits of available traction. No dive means full suspension travel is available to tackle road undulations and thus improve road-holding.
• Allied with the rear Paralever arrangement, the Duolever system allows for near constant wheelbase, irrespective of whether the bike is accelerating or braking hard.
• Compared to the reduced ‘trail’ under hard braking in telescopic fork equipped bikes, the Duolever suspension ensures constant trail and so predictable bike geometry and dynamics over the entire performance envelope.
• The far superior rigidity of the Duolever system leads to better feedback to the rider though it takes time for someone to get the best gains when switching over from telescopic forks.
Also check out these links for more details on the Hossack Suspension
Hossack-Design.co.uk :: Design and Theory
The single-sided swing-arm at the rear with the 3rd generation Paralever system is another excellent piece of engineering. BMW has cleverly combined the drive shaft and the swing arm into one structural element by housing the drive-shaft inside the swing-arm. The increased depth of the swing-arm would have been needed anyways to provide for the necessary rigidity. Check out how increasing depth of a beam increases its rigidity by holding a plastic ruler flat at the edge of a table and pressing down its free end. It is easy to bend it. Now hold it edge-wise and the same ruler becomes almost impossible to bend! The Paralever system forms a structural parallelogram much like a double-wishbone in cars and holds the rear suspension in constant orientation with respect to the rest of the bike during acceleration and braking. The earlier Monolever would let the rear wheel ‘ride’ up the shaft under acceleration making the rear end squat sharply, something that was unnerving with throttle changes during a turn. The Paralever now adds tremendously to the bike’s lateral stiffness, so much so that the engine has been made a stressed member of the bike frame and the swing-arm has been mounted directly to it. In this 3rd generation system, the control arm has been moved above the drive-shaft thus increasing ground-clearance and the rear drive has a hollow axle to save weight. As for the benefits of all this sophistication, you get exceptional straight line stability at all speeds and perfectly neutral steering that simply and effectively follows the rider’s steering inputs to the‘t’.
All right…enough on the suspension phew! Braking on the K1300S is phenomenal…period. The lever did feel a trifle spongy at first but once the brakes were used on the move, the feedback and sharpness was nothing short of near perfect. Combine that with an efficient ABS, there’s loads of peace of mind for the rider attempting emergency stops. The 320mm four-pot front dual discs seem capable of stopping a freight-train, what of a motorcycle. Add that inherent anti-dive from the Duolever front and what you get is surer and stronger stops than any. The brakes are configured such that using only the front also operates the rear while using the foot pedal operates the rear disc alone. There’s the ASC (Anti-Slip Control) that is a form of traction control which prevents the rear from spinning under acceleration under low traction conditions. It sure blunts the sharpness of the power delivery but under low traction conditions like wet, slushy or gravel-strewn roads, the edge could well take the rider over the edge. So thank you for modern electronics.
The lights are good with a nice broad beam-spread and are bright in intensity. The low-high beam selector is built into the day-flash switch itself – press the switch lever inward to flash the lights and pull it outward to switch to high beam. The horn in typical European ‘polite’ fashion was weak for our roads and not taken seriously by other road users. The turn indicators are on the left handlebar switch cluster much like on the Japanese bikes, a welcome change from the earlier BMW tradition of mounting them on the right side. The handlebar is just wide enough to provide good leverage for low speed control but the bike does feel heavier at typical urban speeds than it actually is. The seat is plush and roomy, both for the rider and the pillion. But the plushness could mean that long stints on the saddle could become tiring in the absence of a firm support underneath. The foot-peg, seat and handlebar relationship does feel spot-on and the slight crouch helps you get behind that substantial fairing up front and so out of most of the wind blast. The mirrors, as mentioned earlier are pretty functional, clear across the rpm range and look trendy with those built-in trafficators.
We did not have the bike for long with us but the on-board info indicated a fuel consumption of 7 ltrs/100kms which comes to about 14 kmpl – not bad at all for what lies between the wheels and the way it makes those wheels go! The range is again about the same as any big bike sold here – with a 22 ltr tank, you ride about 250 odd kms before needing to refuel. Of course a compression ratio of 13 demands premium 95 octane or higher fuel.
The K1300S is a hyper-tourer par excellence. A tad unexciting for some but when it comes to stretching those long legs on endless tarmac that stretches beyond the horizon; I would unhesitatingly pick this suave well-heeled Hulk as my ride.