Many thanks, EA and bt. Between you, you have given me the information for which I was searching. My car is definitely running much more smoothly since the tyre change and I have given myself a margin of 500 miles during which I will take things somewhat easier than normal (not that I am a boy racer type anyway).

bt, the report to which you provided a link is the most comprehensive article about tyres and wheels that I have ever seen and should be compulsory reading for anybody who drives.

In practice with air driven tools they will probably be OK

Any tyre fitter who simply tightens wheels with an air gun should be sacked. Different cars, different wheel specs all have different wheel nut torques, an air gun does not know this and will normally be set to a high figure so that it loosens off tight nuts/bolts.

Overtightening is simply pointless and potentially dangerous, it damages wheels, makes it near impossible to remove the nuts with the supplied wrench and potentially damages the studs/threads.

Its fine to fit the nuts with an air gun but it should be set to a suitably low torque figure. The nuts should then be tightened to the correct figure using a torque wrench. The last few times I have had tyres fitted this proceedure has been followed be it at an indy or places like ATS/Kwik fit.

I don't think my issues were related to the tyres being new as I'd done ~1,000+ miles when I had issues.

However posters did report that tyre mounting compound may persist on the tyres for a few hundred miles, making them slippy, so as said, take more care for the first week or so.

Tyre mounting compound is only brushed onto the tyre bead to ease mounting. It is not brushed onto the tread thus will not affect grip.

Tyre release compound is introduced into the mould when tyres are manufactured. Since it is a lubricant it does affect the grip of new tyres but normally wears off in well under the 300 miles recomended by the manufacturers.

But new tyres do take time to settle into the car and achieve their maximum grip, especially in wet or snowy conditions. Several years ago a chap at work awoke to find the street covered in snow. His tyres were low on tread thus he went and had 4 new ones fitted. He quickly found out how little grip a brand new unscrubbed tyre offers in such conditions, but luckily without involving anyone else.

Really informative and interesting thread. :)