The Case for Grooves
	by Tom Keeble, England

In order to look at the effect of grooves, we must know what they actually do. The basic concept behind grooved tyres is this: the grooves reduce the amount of rubber in contact with the ground, so the car has less grip. If the car has less grip, the driver must take corners slower. Safety Lets face it, cornering speed is the big issue. Apart from catastrophic mechanical failure, a driver loses control of the car almost always when entering, taking, or exiting a corner. Here, simple physics takes hold: the slower a car is travelling at the moment of impact, the less energy from the impact will be transferred to the driver and thus the chances of severe injury are reduced. The nature of grooved tyres is such that the driver must take the corner slower, or not take the corner at all. So if they lose control, they are likely to suffer less harm than if they lost control at the same point driving the car on slicks. I am sure you've heard that a car spinning out of control on slicks slows faster than on grooves. Well, that's true if they are travelling at the same speed. However, in our case, we can prove mathematically that the car on grooved tyres will actually be travelling slower from the point of braking into the corner, through losing control, to sliding to a stop. If the car hits anything at any point, it's travelling slower than if it was on slicks and is therefore safer. Surely, it's a bad idea to have all-weather tyres for wet and dry conditions? Well, not for safety purposes: dry speeds will be slower (a consequence of a compromise tyre) and wet speeds will be much reduced. So in the event of an accident, there's less speed and less chance of injury. Despite the apparent nonsense of reducing grip to increase safety, it really is as simple as that! There is another reason for lowering cornering speed. The FIA had many chicanes added to circuits in an attempt to improve safety since Ayrton Senna's and Roland Ratzenberger's death. This resulted in the current 'point and shoot' form that most circuits have today; good for safety, bad for overtaking opportunities. Moving to grooved tyres to cut cornering speeds will actually allow circuits to drop the chicanes - ironically, bringing back the full-blooded corners that were to be experienced in the Grand Prix of old days. Competition and Entertainment One of my favourite F1 memories is the closing laps of the 1992 Monaco GP. Nigel Mansell, after a puncture, came out behind Ayrton Senna and the most enthralling fight I've ever witnessed began. Senna successfully defended his position against the determined Mansell, snatching a truly remarkable victory from the Englishman. Had overtaking been too easy, Mansell in the all-conquering '92 Williams would have stormed past and cruised home. Thus, too much overtaking may not be such a good thing. The balance has swung too far the other way, however. The classic overtaking manouevre is to outbrake an opponent into a corner, then avoid being repassed on the exit - something that requires adequate braking zones and driver skill. Consider the effect of grooves: a driver must take more speed off the car when braking for a corner, with approximately the same braking efficiency, so they must brake earlier. Therefore, the braking zone is increased. The car is more sensitive to the drivers' skills in cornering - it's harder to recover from straying over the edge of performance, so mistakes are punished. Skilled drivers following behind can capitalise on the mistake to make their own progress up the field. As an example, recall Suzuka '98: Michael Schumacher was stuck behind Damon Hill's Jordan until a pitstop moved him behind Jacques Villeneuve in the Williams. He could not pass because Damon made no mistakes. Villeneuve, however, made a small mistake in the hairpin and the Ferrari was through. Why? Grooved tyres punished the mistake heavily, as the small error cost a lot of exit speed. Michael Schumacher skillfully put himself in a position where he could capitalise on this error. As an added bonus, mathematical models show that any fixed percentage reduction in mechanical or aerodynamic grip can close the gap between the big and small teams. Admitted, Ferrari and McLaren have the finances to react quicker to the changes, but from the season after a change of this nature is introduced, the small teams will find themselves posting times closer to those the big boys manage. Costs The move to grooves must, initially, have increased costs. A whole new tyre methodology had to be brought into being to handle the new structure. However, the change to wet and dry tyres will provide a marked reduction, as the teams will only have to test a single type of tyre; halving the development time and costs devoted to tyres whilst manufacturers will have to produce tyres of a single type, slashing their own costs. Applicable to Road Cars Road tyres have grooves and are run in the wet and the dry. Spot the resemblance? If it's good enough for F1, it's good enough for your performance road car too. Manufacturers will be more credible in advertising a connection between success in Formula one and the performance of the tyres they sell to you and I. End of subject. Conclusion Improved safety. Return of the full-blooded circuit. Increased overtaking opportunities. Reduced costs. In return for what? Tyres that don't look right, and lets face it they don't! If they should be banned, that is certainly the reason; but it's the only one. People argue that F1 should be the pinnacle of motorsport, and I think that it is. Let drivers have their slicks for other Formula. They'll need them to get used to the high speeds they'll have to handle in the high speed, low grip, and above all - skilled world of Formula One.

Tom Keeble	© 1999 Atlas Formula One Journal.
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