Maybe measure the tyre thread left and if there's a noticeable difference between the tyres get it rotated.
Yes, I recall those days too. A factor that applies now that is fairly new is that often tyres are rotation direction dependant. That is, a tyre could no longer be switched from nearside to offside on the same axle because it would then rotate in the wrong way.Thanks for the replies. I don't really fancy the idea of having to replace all 4 in one go and, barring any punctures, that would mean replacing 2 at a time on the same axle. I had an issue with my Ampera when new tyres were put on the rear and then on certain corners (not even winging it round the corner) the traction control light would come on and the stability control would kick in. After a bit of discussion in the Ampera pages, it seems that there was enough differential between new and worn tyres to make the car think that grip had been lost on one of the axles. The Ampera was only FWD and I am more concerned with this sort of reaction to two new tyres on one axle and two worn on the other.
I will get the depth checked and see how they are wearing.
I remember seeing in a handbook, possibly my first car how the tyres were meant to be rotated using the spare-
Spare to the front offside, front offside to the rear nearside, rear nearside to the read offside, rear offside to the front nearside and the front nearside into the boot. Maybe it was a carryover from the days of old cross-ply tyres.
The American tyre wear being better could well be because they don't have as many windy roads and the long straight freeways.