With road cars, we use all-weather tyres and such was the case in Formula One in the early days. It was not until the second race of 1971 at the Montjuïc street circuit in Spain that Firestone introduced slick tyres to F1 for the first time. Tyres are obviously the only part of a car in contact with the track and their effectiveness is probably more important than any other performance factor.
That Spanish race in ’71 was the beginning of specialist modern tyre technology which soon saw Firestone and Goodyear pushing Dunlop out of F1. Conversely, since slicks were hopeless if it rained, specialist wet tyres were developed. These rain tyres were treaded to dispel water and softer than slicks to grip at the lower temperatures the wet track caused.
In wet-dry conditions, the anguish for drivers and teams was when to switch from wets to drys or vice versa. Stay out too long on slicks as the rain came down and a driver could easily crash or lose 10-20 seconds in a lap. Stay out too long with wet tyres on a drying track and they began to melt, but stop too soon for slicks then stray off the dry line forming on the track and a visit to the scenery quickly followed.
Ayrton Senna is best known for his wet-dry prowess (except maybe Michael Schumacher) with perhaps his most renowned victory at the 1993 European Grand Prix. This was not just a result of his ability in the wet on rain-tyres but also his ability to stay out on slicks, as he did later in the race, when the rain returned, and still be fast when others had to pit unable to cope without wet tyres.
In 2001, Bridgestone introduced the intermediate tyre to combat the return of Michelin and tyre-competition to F1. The intermediate was a lightly treaded tyre, harder than a wet tyre and slightly softer than the slicks. (In fact, into the ‘eighties, especially if a race was starting on a drying track, teams sometimes hand-cut grooves into slick tyres but the practice was banned.) At the second race in Malaysia, the skies opened early in the race. Rubens Barrichello had just overtaken Ferrari team-mate, Michael Schumacher by taking a shorter route across the gravel trap as they both slid off on oil. The safety car was deployed and both Ferrari’s ended firmly at the back of the field having been fitted with inters whilst even the other Bridgestone runners thought full wets the way to go. Ferrari finished 1-2 with Schumacher lapping five seconds a lap quicker as the track dried and able to stay on his inters outpacing everyone when all the drivers on wets had stopped for slicks. When he did finally make his only fuel stop and switch to slicks, the battle was over.
The current intermediates are softer than they used to be hence in China a lot of drivers having problems with the treads going bald. Indeed, Button gained from earlier on staying out on slicks when most pitted for inters and preserving his inters better than others later in the race. No more can drivers stay with inters onto a dry track before being absolutely safe to move to slicks.
However, my proposition is to ban intermediate tyres altogether. They were introduced for tyre-company competition that no longer exists. It will save money for any company thinking of becoming the F1 tyre manufacturer. Above all, it will make wet-dry races even more dramatic and exciting. Who will dare to stay out longest if it rains a bit? When it is drying out, who will dare switch to slicks first? Will it be too soon? The gap between wet and dry tyres will really test the drivers and the team calls. I remember watching Indycar in the ‘nineties before the split and the excitement of wet-dry races without inters was epic. Let’s bring that back to Formula One.
(One of the best finishes I ever saw to a race was the 1997 CART race at Portland when Mark Blundell out-dragged Gill de Ferran after the last corner with Blundell on slicks on the wet part of the track and de Ferran on the dry line on wet tyres. See a 50-second clip on YouTube. Also for UK users only, 12-minute highlights of the 2001 Malaysian GP from the BBC.)