Feeling Deflated

As of this week, we have managed to get a total of 4 flat tyres on the cars over the last year. That's equivalent to an entire set. Two of those flats have been simple nails in the tread and have been easily repaired. The other two have been tears in the side wall which have necessitated a new tyre. On all occasions it has meant fitting the space space-saver tyre and heading down to the local tyre fitters. Space saver tyres are far from ideal but they will, at least, allow a gentle run home or to the nearest fast-fit centre. Increasingly, cars are not being fitted with a spare of any type and instead get a "can of gunk"  which is intended to plug and inflate a punctured tyre until they can be changed. Personally, I'm not convinced.

Part of the reasoning behind the tyre emergency repair kits is to save space and weight. Saving space means that the car is more functional (bigger boot etc) which is good. Saving weight means that the car will use slightly less fuel. This is good to a point but it does mean that if a tyre goes flat the emergency can needs using. For our punctures, this would have worked for the simple nail in the tread but we wouldn't have been able to get the tyres repaired: once the gunk is used they have to be replaced. For the two times we had split side-walls we would have been completely knackered as the gunk can't typically deal with this - the only solution would have been a call to the AA (or a mobile tyre fitting firm). Whereas the cost saving from the reduced fuel consumption is welcome I can see this being completely overridden by the extra cost of the replacement tyres. Of course, the car companies are quite keen on dropping the spares. Partly this is to save on costs (a spare will add to the vehicle cost) but it also allows them to reduce the official CO2 figure which buys all sorts of tax benefits. However, if the additional cost is writing off perfectly serviceable and repairable tyres or dragging out the AA with a pick-up truck and then scrapping repairable tyres then the environmental saving is somewhat of a mirage.

One possible other solution is to use run-flat tyres. These allow the driver to carry on driving at reduced speed for a short while - theoretically enough to get to a repair centre. BMW fits these on many cars and one of my colleagues can attest to their effectiveness - although by the time he made it to the tyre centre the tyre was damaged beyond repair. However, the problem with many run-flat tyres is that they have significantly higher rolling resistance then the equivalent standard tubeless rubber. This means that any fuel saving from the weight reduction is lost back at the tyre. Having said that, I can see the advantage of not having to get out and change the thing. Usually, when I have to change a tyre, I am stuck in some sort of monsoon conditions and end up losing my rag like a scene from The Incredible Hulk:

One of my colleagues has just bought a VW Up! Which does not come with a spare as standard. Apparently VW offer a full size spare as an optional extra and I advised my colleague to go for this. Whether she would be happy changing the tyre herself is another matter. As for the space in the car, I don't think it compromises it too much. The Up! is remarkably spacious for a city car. In fact they seem to have copied the best bits from the Toyota Aygo and fixed the downsides (the Up! actually has a usable boot space). The optional spare was £50 - I suspect that a call-out from a breakdown firm will cost at least that much.