Car designers to bid adieu to spare wheel!

Cologne, August 15:

The spare wheel has been an essential part of motoring for more than a century and the bane of progressive automotive styling for just as long. Its days now appear to be numbered, and few are already mourning its ‘demise’. In the early days, these bulky items took up space strapped to the side or to the rear. Over the past 50 years or so, they have generally been stowed in a scarcely accessible recess in the boot. In recent years, the spare wheel has been slimmed down — many models carry an emergency wheel with a tyre having much less road surface. They are designed purely to get the motorist to the next service station. The military have long used tyres capable of carrying on even after being shot out. Limousines for senior politicians, VIPs and others deemed a security risk have for some time made use of them.

Now this technology is coming to production line cars. BMW is including neither spare wheel nor the accompanying jack and spanner with its new 1 and 3-series cars. The 1-series has been designed without the spare wheel recess altogether, while in the 3-series, the recess is empty and is designed to stow damp items, according to company spokesman Rudolf Probst in Munich.

Motorists insisting on a spare will have to pay extra for it. Goodyear technical expert Holger Rehberg in Cologne notes that these BMWs are by no means the first general production cars to do without spares. “BMW’s Z8 and Z4 were designed without the recess, and some Ferraris and the new Porsche 911 are similar,” Rehberg says. “In 10 years, I think there will be no recess for the spare tyres in new cars,” the spokesman for the tyre maker says. German automotive researcher Ferdinand Dudenhoeffer, a professor attached to a technical college in Gelsenkirchen, has a similar view. “It is conceivable that in a few years we will be doing without the spare altogether,” he says. Probst says that BMW’s strategy is to omit the spare where it believes there is no need for one. Car designers are happy. “Omitting the spare recess offers makers more freedom in designing vehicles,” says Helmut Klein, who works for the German ADAC motoring association in Landsberg am Lech.

In its 1-series, BMW has used the space to enlarge the boot. And it also saves 12-20 kg in weight, an important consideration. This is all being made possible by so-called ‘Runflat’ tyres, which allow the vehicle to continue a long way after the air has gone out of the tyre.

“A standard tyre collapses when the air goes out because the walls fold over and wear away quickly, if one carries on driving,” Goodyear spokesman Rehberg says. Goodyear’s Runflats have special supports in the walls of the tyre. “The tyres then no longer go flat in the old sense,” according to Rehberg. Tyre maker Continental in Hanover has two different systems. One is similar to that used by Goodyear and is intended for sportier cars with a smaller tyre profile. In general, manufacturers are aiming to have the emergency tyres run for at least 100 km and in some cases much more. But the new Runflats have their disadvantages. They have a harder ride as the supported walls are not as flexible, and they are heavier. “When we started, these tyres were about 25 per cent heavier. Now we have got that down to 15 per cent,” says Rehberg. Runflats are around 20 per cent more expensive than conventional tyres, but this is still less than the cost of a spare wheel and tools for changing the tyre.