Hey guys I just put my rims on today. I installed 245/40/18 all the way around. When i hit about 70km/h it starts to vibrate a little bit. When i move up to 80km/h it shakes pretty good. But after i get over 100km/h it seems fine....I asked my mechanic if he balanced them and he told me he did so anyone else have any ideas whats wrong with them??