Tyred

I went to the local Kwik-Fit after work today to get the front tyres changed, for a reasonable amount - £70. That includes a small payment for the old tyres to be economically disposed of. There! Can’t say I don’t do anything for the environment now! They jacked up the car manually, rather than driving it onto the rack, so I didn’t ask them to check the front brakes. I just did a hard stop when I drove out of the garage and managed to feel some difference. Most of the pressure is on the back brakes anyway.

While I was in the shop waiting for the tyre change, this guy came in for tyre changes on his car, a nice shiny VW Golf. The mechanic is apologetic but can only offer the medium-priced tyres. "It’s not a common car," he explained. "We usually only stock tyres for the GTIs."
The man asks for GTI tyres anyway.
"The difference in depth can throw off your speedo," the mechanic says. "You could be doing forty and the speedo says thirty."
The man looks at him in disbelief.
"Yeah," continues the mechanic, "that’s how much the wrong tyre can affect your car."
I’m not sure whether to believe him. I guess there is a truth in it as the speedo is calculated by the revolutions the car wheel makes, and the wrong tyre would make a larger revolution than needed, but surely the speed of the car (and therefore the speedometer) would reflect this? The guy shrugs his shoulders and reluctantly starts fishing out his cash. I felt a bit sorry for him.