[CharlesJones]

Interesting stuff, but basically what this seems to boil down to is the importance of using grippier tyres in the rear than in the front. It sounds to me like the danger of mixing tyres is the rear losing adhesion before the front ones, whether thats because they are just less grippy tyres, not so grippy as the fronts in the wet, or have different warm up characteristics. So in theory as long as you ensure you get better performing tyres for the rear, everything should be okay, although you have to be sure they have greater traction in all conditions. Hmm... I see your point - the only certain way of doing that is to get matching tyres front and rear. Or buy Nangyangs for the front!