Just mounted a set of 18" wheels about 50 miles ago and have a question. I'm getting a little shimmy right at 70MPH that I can feel through the steering wheel. It smooths out around 75. Are the larger wheels prone to this sort of thing, or should I take them back to where I had the rubber mounted and balanced and have them re-check the balance? In case it matters, here are the wheels and tires I'm using: Alt 252, 18": http://www.lakeshorewheelandtire.com/custom/alt-wheels/AT-252-Silver.shtml Hankook Ventus V12 evo K110 Thanks!