roll on the summer tyres

I received that text a few days ago to remind me to swap back to summer tyres. And yes, spring is indicated with a late night hedgehog in the back garden on the prowl again. There are certain - er- signs.

So, I'm dropping the car in for a pit stop today. I'm wondering if the summer tyres might also need an update at this point. They are certainly legal, but may be getting close to that 3mm point where they ought to be replaced. Foolishly, I forgot to get the measurements when the wheels were sent off to Poole for the winter.

It can be hard to get too excited about tyres, although they are the thing that keeps the vehicle on the road. Like in cycling, the rule is to keep the black bit pointing down.

I decided to take a quick look the web-sites advertising tyre replacements. There seemed to be several categories.

• The ones that imply "don't you worry about this, we'll handle it all for you whilst you sit in the lounge drinking coffee and using the wifi"
• The ones that scream "Price comparison - we have whatever you need cheaper than anyone else"
• The type showing racing cars and pumping music with a hedgehog being swerved around.
• The fancy films with complicated diagrams explaining long chain polymers for rolling resistance and efficiency, short chain polymers for cornering and braking, the silicates, carbon black and cross linking agent.

For me, the diagrams about stopping distance seem more important. Tyres grip loses efficiency geometrically with wear(slower at between 8mm-4mm then dramatically speeding up after about 4mm). There's a well known chart.

And the effect of the same thing on stopping distance...

So when I'm sitting in my comfortable dealer lounge waiting to get the car back, I'll be expecting something with all the right polymer chains, at a good price and that is kind to hedgehogs.