got 4 nice new goodyear f1`s about 3 months ago. now 3 hav got loads of grip on still BUT the passager side rear is at the illegal limit. WHATS HAPPENING??? what sud i do? sud i just change the 1 tyre? im just really confused about this & sum input wud b great thanx...........michael.

 

Assuming there's nothing wrong with your suspension/alignment/pressures, check that all the tyres have the same markings on the sidewall.
Many years ago I bought some Goodyear NCTs, they felt really strange. I found 3 were from Germany and one was from Africa. Totally different compound, made for high temperatures, no grip at all.
Some kind of grey import that got into the supply chain apparently.....Just a thought......