The Power of Balance
MotoGP racers talk about it, road bike engineers strive for it and, if your bike’s got it, riding really, really quickly is easy. But what the hell is balance?
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54 years 8 monthsINSTRUMENT OF DIVINE BALANCE 1: SUZUKI GSX-R750 K9
Perfect power 132bhp instead of the 1000’s 165bhp means quicker steering, less weight and less fear. GSX-R600 chassis. Compact and shrink-wrapped around the tiny engine, the small chassis swells confidence.
Underslung exhaust. Not original but crucial to centralising the mass, something many balanced bikes share.
The original GSX-R750F was the child of two parents; Suzuki's World Endurance programme (which went from reliable, fast but weighty GS1000-powered prototypes in 1980 to the honed XR41 works racer and the title in 1983) and European market research that concluded road riders might well buy a road-going XR41 of their own should one be made available.
Combining a then innovative aluminium frame, a uniquely lightweight and high performance oil cooled motor and styling that was pure endurance racer (the first GSX-R750 prototype, unveiled at the 1984 Cologne motorcycle show, was pure XR41, just as two generations of Fireblade (2004-2007) were pure RC211V MotoGP racer) the GSX-R750F was truly original in a way few new sportsbikes have been since. And, unlike those Fireblades, Suzuki's race-replication went deeper than plastic. With absurdly lively geometry (steep head angle, short wheelbase), a peaky but competitive engine and, most importantly of all, a refreshing lack of weight (Honda's VF750 Interceptor and Yamaha's FZ750, both of which were liquid-cooled, made similar power but weighed between 25kg and 50kg more), the GSXR750 was a balanced rapier of a machine, one that asked questions of the general public's riding ability and, in many cases, found it wanting. For a modern equivalent imagine one of the Japanese big four coming out with a carbon-framed 1000 that made a class-average 165bhp but that weighed some 140kg and flirted with instability so shamelessly the aftermarket grew fat off the back of a steering damper gold mine.
Now imagine also that a couple of win-hungry individuals got hold of said carbon-framed work of fiction and, with little more than a race cylinder head and an exhaust, turned up at a superbike meeting to kick ass, perhaps with an unknown American racer by the name of Kevin Schwantz in the saddle. For proof of the GSX-R750F's balance of strengths and fundamental rightness you need only consider the 1986 Trans-Atlantic races. Kevin Schwantz flew in to race at Donington with nothing more than his riding kit; he had no bike. By contrast fellow American Fred Merkel had a Honda worth half a million dollars.
Suzuki's Martyn Ogbourne left a rubber cheque for a GSX-R750, hastily threw a few Yoshimura parts and some lightweight wheels at it and Schwantz, having grown up on America's counter-clockwise tracks, promptly hopped on and turned right out of Donington's pitlane. But despite the inauspicious start Schwantz would leave the UK a legend, having diced with Merkel, pulled off the mother of all saves and shown the cream of British racing talent the meaning of bravery. Sure he was Kevin Schwantz, but the bike played no small part. "I wasn't that impressed when I first saw the motorcycle but when I got to ride the thing it was actually quite the machine," says Schwantz. "It was real fast and real light." The GSX-R750's form has waxed and waned ever since, Suzuki spoiling its balance some years only to restore its status as the complete road sportsbike the next. Fortunately Suzuki have stuck with the capacity though, and the GSX-R750 K9 is a good one. Try it. Feel the power of balance.
After a test involving the Suzuki GSX-R750, chances are you're already sick of the B word; balance...
...well, sorry, but it’s difficult to dismiss the “best of both worlds" cliche when it's coming from riders of James Whitham's calibre. And when a bike with a pretty unique blend of power and chassis geometry (the GSX-R is the sole surviving sports 750) wins so emphatically ahead of two machines as talented as the Ducati 848 and Triumph Daytona 675, something must be afoot; perhaps there's something to this balance thing?
If you're a race fan, chances are you've been hearing the B word a fair bit recently, usually in reference to a Yamaha, be it the 800cc M1s of Valentino Rossi and Jorge Lorenzo or the superbikes of Ben Spies or, in the British domestic series, Leon Camier and James Ellison. In each case the story is, according to our esteemed commentators, the same; no power advantage and, given that control tyres are mandatory and most machines close to their series’ weight limit, no weight or grip advantage either. Instead balance is apparently the winning difference they have in common.
And it would seem this balance stuff is pretty potent. Camier is 113.5 points ahead of team-mate Ellison and a scarcely believable 156.5 points ahead of the nearest non-Yamaha, Stuart Easton's Fireblade. Together Rossi and Lorenzo have pushed Yamaha 66 points clear of Honda in the 2009 MotoGP constructor's championship; 230 points to 164.
"When people talk about balance with regard racing motorcycles they're talking about a balance of qualities," explains MotoGP technical journalist Neil Spalding. "At the end of the day a bike's just a heap of bits which, when put together, has a certain character, certain strengths and weaknesses. A balanced bike is one that allows a rider to use all of its performance. So for example there's no point having the bike with the most grip if it makes so little power it can't make use of all that grip, just as there's no point building the most powerful bike if the rider hardly ever gets to use all of that power [the latter is a common trap in racing circles. Mick Doohan famously fell out with Honda when HRC's engineers went blindly chasing horsepower and built an inferior NSR as a result]. In superbike racing at the moment it's pretty common to tune the engines for more power and torque, only to then have the electronics piss away a fair bit of that torque because it's counter-productive. A more balanced bike wouldn't make the additional torque in the first place."
All of which rings true with the GSX-R750 test. Even a standard GSX-R1000 has so much power most riders struggle to deploy it on a racetrack, let alone on the public road. And yet the GSX-R1000 is compromised a little by its additional power, being a shade heavier, a little slower to change direction thanks to its wider rear tyre (190/50 compared to the 750's 180/55) and a whole lot more intimidating given its huge grunt. As a result the 750 is the better-balanced option for most riders, with the confidence building feel of a 600 but a more versatile engine. Th e 750 isn't the lightest or the most powerful of the GSX-Rs but it is the most balanced.
It's the same story with Yamaha's M1 MotoGP racer, which has helped set the 2009 season on fi re by being, well, not great at any one thing. "The M1 is widely regarded as being a balanced motorcycle," continues Spalding. "It's not the highest revving 800, nor the most powerful, but it
is the best combination of compromises for a given racetrack on a given day. It's also easy to set-up within the limited amount of practice time available to the teams this year, which has changed the game. It's no good having the best bike out there if it needs hours of work to reach its full potential. The Yamaha can be on the pace very quickly.
“At the end of the 990cc MotoGP era I'd argue the Ducati was as good as the 800 Desmosedici is now, it's just that it took hours to set-up properly. Th e best race bike is the most balanced bike; it's not the best at any one thing but it is the least worst at all of them."
While Neil hints at user-friendliness with regard the M1's easily sorted chassis, James Whitham believes that trait – user-friendliness – goes hand-in-hand with balance. "When you talk about a balanced race bike it means you get a nice feeling from it," says James. "Th ere may not be one thing that stands out about it – chances are it's not aggressive, really powerful or very front-heavy – but that means there's nothing to stop you going quick on it. Balance is a word that covers everything and doesn't really apply to much, but in essence it means a bike you can get on and be happy with; a bike that gives you feedback.