I've just bought a used Porsche 911 Turbo and the front tyres are the originals by the look of them. They've got plenty of tread left, as they've only done 8000 miles, but they're probably seven or eight years old. There's cracks in between the tread blocks. As an engineer, I know this means the tyre is weaker, and I would've thought that a dealer selling this sort of car would've quickly replaced them, such is the force likely to go through them in this sort of car. The problem is that as far as they're concerned - and as far as MoT regulations go - they're okay. I wanted to know if there's any precedent that would make them reconsider fitting them, as it seems crackers that a car with cracked perished rubber would be deemed fit for the road?