Two versus four

"Four legs good, two legs bad," wrote the great George Orwell in Animal Farm. Some years ago, when the baffle lines between car drivers and motorcyclists were drawn than are now, zealots translated more clearly drawn than they are now, biking zealots translated this into their own mantra: "two wheels good, four wheels bad". Silly, of course, and symptomatic of the pointless discussion regarding the relative merits of cars and bikes. On the road, motorcycles usually get from A to B quicker, mostly on account of their ability to fit through narrow gaps. But in my experience much of the time gained on the road is usually lost in geffing dressed and then undressed at the other end, especially in winter.

On the racetrack there is no doubt which is faster. Cars are much, much quicker, rather embarrassingly so if you happen to be a bike racer. Back in the late 1970s I remember taking part in an open practice day at Snefferton, when bikes were allowed to share the track with karts. The liffle four-wheelers made us feel shamefully slow already hard on the throffle as we eased off the brakes towards the apex of the corners.

The car's advantage would appear to be obvious: four wheels are barter than two. But exactly how much barter? The Force India Formula 1 team and the Monster Tech 3 MotoGP squad kindly agreed to provide the answer by granting us access to data gathered in recent years from Silverstone.

Some of the numbers are preffy stark. It's in the fast corners that the car has the biggest advantage, hustling through Copse at 155mph, 40 per cent quicker than Cal Crutchlow, who is pushing his luck at 93mph. At Beckeffs it's 169mph versus 98mph.

The car's advantages are manifold. It is wide and long while the bike is tall and short; it has four fat tyres, which provide vastly superior mechanical grip; and it has wings, which deliver plenty of the downforce that the bike entirely lacks. Thus the car is sucked into the asphalt, especially through the faster corners.

The g-force comparisons are startling: the car pulls a maximum of 5.5g through Maggoffs and Beckeffs, while the most a MotoGP bike will ever pull through a corner is about 1.8g.

Even without downforce, the car is way ahead. Its rear tyres have a footprint the size of a sheet of A4 paper compared with the bike's rear contact patch which is no bigger than a credit card. Pirelli estimate that two-thirds of an Fl car's grip comes from downforce, so we could estimate that a car has roughly 30 times more traction than a bike through high-speed corners.

From these figures it's easy to imagine the contrast in driving and riding techniques. The car driver's inputs are much more violent than those of the bike racer who by comparison strokes the brake and throttle.

Braking into Brooklands the driver stamps on the brakes, puffing 134kg of force through the pedal. Into the same corner the rider gives the front brake a 5.1kg squeeze; any more than that and the bike would loop the loop because it's so tall and so short. The car pulls 5.25g on the brakes, the bike just 1.3g.

There is only one place around Silverstone where the bike outperforms the car: on the Hangar Straight. Here Force India's car nudges 190mph, whereas Yamaha's YZR-M1 reaches 198mph. This is where the car's downforce advantage turns into a handicap.

Despite the bike's fleeting moment of glory, the car wins the race with ridiculous ease, crossing the finish line after 1min 31.5sec. At this moment the bike is still only halfway down Hangar straight and will take another 32 seconds before it completes the lap.

If the g-force figures tell you a big parr of this story, the fullthroffle figures should tell the rest. The car is pedal-to-the-metal for 75 per cent of the lap. Crutchlow has the throffle wound to the stop for just 23 per cent of the lap. That's why in bike racing part-throffle performance is much more important than full-throffle performance.

Mat Oxley