Tyres, and Grip, and Which Class Future MotoGP Riders Will Come From
At the start of the MotoGP era, speculation was rife that the entry class for the senior class was no longer the 250s, as it had been for years, but rather the Superbikes, where experience of big torquey four strokes was felt to be a possible advantage in the new class. Tyres with too little grip for the power output helped reinforce this impression.
But as grip increases, with tyres and engine management learning to sing in perfect harmony, the route to MotoGP is shifting back to the 250s, just like during the 500cc period. Back in the days of the 500s, few riders tried to make the switch from Superbike to 500cc, because they were such totally different beasts, requiring wildly different riding styles. The only successful route to 500s in the 90's was through the "Stroker School" of 125s and 250s.
The coming of the four strokes to MotoGP changed all that. All of a sudden, riders needed to be able to muscle a heavy, torquey (well, relatively) bike around the track, and a horde of Superbike riders made the switch. Only the very best made a successful transition (Bayliss and Edwards), but the nature of the bikes at least made it possible (Bayliss' fantastic showing in the early Superbike races this season demonstrated his vast talent). The only way to ride the first generations of MotoGP bikes was to brake late, stuff it through the corner, and stand it up as soon as possible, so you can open the throttle without the thing spitting you off.
Now, the tyres have caught up with the power (an extra 50+ horses) and weight (an extra 20+ kg) jump, electronics have become more important, grip has increased, and the bikes have become a fraction lighter and much more controllable. You don't need to stand the bike up before opening the throttle, as the traction control will harness the excess horses, limiting the slide before it throws you off, and the increased grip and strength of the tyres allows you to brake harder and deeper into the corner than previously, so the differentiator becomes how much speed you can maintain through the corner, as opposed to how quickly you can get on the gas. Any speed you don't have to lose in braking is speed you don't have to regain by accelerating. I've said it before, but check out the lean angles, in particular look at how much space their is between the inside of the knee and the tank as the riders corner: The bikes are now leant over so far that as the rider's knee sliders kiss the tarmac, there is still only a couple of inches between the tank and the knee. 5 years ago, there was a lot more air there.
And we are back full circle to the Stroker School: riding a small capacity, limited power (well, relatively, after all, a 250cc race bike "only" makes 100+hp) racer requires you to hold on to as much speed as possible. Gaining speed is a lot harder on a bike with less power and not much torque than holding on to it. The best example of this are the 125s: It's amazing watching those kids (most of them are still teenagers) wring the necks of the bikes all the way round the track. The ideal lap seems to consist of assuming a racing crouch, holding the gas open, and maintaining that position for as much of the lap as possible, without being spat off. You really can't afford to scrub any speed off, 'cos those tiny engines, geared high to allow decent top speeds, really struggle to gain any speed at all.
So, over the next few years, expect to see this year's pattern repeated: new riders entering the MotoGP class will come from the 250 cc class, rather than the Superbikes. (This year's exception, Chris Vermeulen, also spent several years racing Supersport 600s, which again require you to hold a higher corner speed than the big Superbikes).
Now, the MotoGP class is a prototype class, but engineering from this class is starting to find its way into ordinary road bikes (such as the rear suspension on Honda's CBR 600 and 1000 RR bikes), and ordinary road bikes (well, the hypersports, anyway) form the basis for the Superbike class. This raises an interesting question: currently, traction control isn't very prominent in Superbikes because it isn't available in fully developed form on the road bikes which the Superbikes are based on. But as engine management becomes more sophisticated, and more ubiquitous (and, frankly, cheap enough) on road bikes, so it will become more important in Superbikes. This year's Yamaha R1 already has electronics limiting the amount of power in the lower gears to counter wheelying, and this is just the start of a long development process. Arguably, traction control is more useful on the road, where road surface grip conditions can change vastly from metre to metre, than in the controlled conditions of a racetrack.
And the improved engine management and traction control of the hypersport bikes will mean that corner speed will become a crucial factor in the Superbike racing they have spawned. And it may once again be possible for riders to move from Superbikes into MotoGP again. Whatever happens, the way the two series interact is going to be fascinating to watch.