16 Jul 07
It was just one little nail sitting all by itself in the middle of a country lane in deepest, darkest Devon. It wasn't its fault that it happened to be run over by the nearside front tyre of the 335d. But that didn't stop it causing a whole heap of trouble. Welcome to the world of runflat tyres.
At the time it could scarcely have been less dramatic. There was no bang, no dramatic weaving from side to side, just a polite electronic chime - the same you hear when the fuel level's getting low - and a sign on the nav screen saying I had a puncture. I felt nothing. Being inherently suspicious of electronic warnings such as these I stopped the car expecting to see a fully inflated tyre, which is indeed what transpired. So I climbed back on board, cursed the BMW's tyre pressure monitoring system and would have set off again at a fairly hot pace had I not stopped to ponder whether a runflat with no air in it actually looks, well, flat. So I continued to a service station at the proscribed 50mph allowable for the tyre.
It was, of course, Sunday afternoon and I was, inevitably, over 100 miles from home but I did manage to find a functioning air line which revealed the tyre's pressure had dropped from its usual 36psi to around 22psi. It was then I saw the nail and realised the warning system had had a point after all. Had this been a normal tyre, I'd have changed it for the spare and been on my way in 15 minutes. But because it's a runflat there is, of course, no spare. So I had to crawl home at 50mph, which I reckon probably put an hour on my journey home and rendered the runflat unusable thereafter. But it got me home to my family, and for that I am truly grateful.
Then I tried to cure the problem. First port of call was the ever-excellent Paul Jarrold Tyres in Monmouth, who confirmed what I had suspected all along: despite the nail's location in a fairly innocuous part of the tread pattern, it could not be repaired. Indeed the advice was not to repair any runflat that had been run while flat. So instead of a ten-quid fix, I was looking at a new 225/40 YR18 Bridgestone Potenza RFT. Price? In theory £125 plus VAT, in practice irrelevant on account of the fact that his local Bridgestone agent said that tyre was unavailable in the UK. I could have a 225/40 WR18 with a different speed rating but its construction would also be different so I'd have to buy two, replacing the entirely healthy tyre on the other side.
