Mileage is 54 K on the 2011 Camry so I replaced all four tires with Kuhmo tires two weeks ago. For two weeks, I've felt a bumping mostly in drivers seat, not wheel, some shaking at 70 mph. Three trips back to tire dealer; rebalanced, remounted, swapped around front/back, test drove. They decided to replace the set of four, with four new Kuhmos, because I had no problems before the new tires two weeks ago and I think they were tired of me...The new tires are bumping/bouncing too--any suggestions on what is causing this? Kuhmos were recommended and are rather expensive. Thanks for suggestions.