if you read my explanation you will understand!

they dont warp,they get hot-spots,as explained above, next time you get the discs off for a new set because of warping ! go get em skimmed if theres plenty of meat on em,by the way ,standard ford discs go off by the first set if traffic lights there that kak!,then again ive paid just under twenty quid for a set so what dyou expect!

get em on a spindle and see if you can spot the inner edge warping as you spin the disc then,it wont happen ,unless its been smacked with a sledgy or been in an accident.

you have to get decent discs,ebc,black diamond,tarox,hi-spec,red dot,etc.