as the title says...it only seems to happen after driving say on the m-way at about 90-100,then when i slow down to 80 or less i get quite a bad wobble on the steering wheel that lasts for about 30-40 seconds then it stops,but as soon as i do it again it happens again.:(:(
ive just had 2 new tyres on the front and they've both been balanced,and it still does it:(any help will be much appriciated.

cheers
BM