I am running Goodyear Duratrac 315/70r17 and just had them rotated (5 tire rotation) with 5,000 miles on them. I have had a shimmy in the steering wheel at about 45 - 55 mph since the rotation. I have had the front tires balanced three times and it is still there. The last two times the shop said that they had road force balanced them. Shimmy is still there. Am I missing something here?