Smaller diameter rims, larger diameter tires will help soak up some of the bumps, but there is a trade off, when taking high speed corners there is more roll on the tire cuz of the higher sidewall and more chance of tipping over. Just an idea. I live in Maine and the roads are hell, I have had a few cars w/ 17" rims & low profile tires. I get 16" rims and put on a set of 65 series tires and it helps, you just have to drive differently.