I had an interesting problem that started several weeks ago.
Heres the story:

I bought my car with oversized tires on the back, 235s, which look great, and i havent had any problems with the oversized tires until i bought new tires for my car. I began to notice that as i hit bumps i heard a pretty nice "turrrrhh" type of nice, sorta like ripping a thick piece of paper...or rubber in this situation. At first, i just noticed a slight amount of the rubber being ripped off on the tire as i hit bumps, but nothing serious. Little did i know that my rear right side air shock was leaking air. 2 weeks later, the bumps got more serious on weaker bumps, and eventually i carved a nice canyon into the side of my tire. So i finally acted, and changed the rear shocks, which changed my fenderwells from being 1inch above the tire, to nearly 3 now. Although the bumping has stopped now, my tire is still torn (and probably not really safe to drive on) and my car looks like a dragster because the rear is so much higher than the front. Kinda awkward, and not my style, id rather my car be lower than the stock height, but you cant get everything you want, can you? Safety first.

just a story for you guys...

 

maybe find a set of used rims with the right back spacing so you can unload those air shocks

 

My car sit a little lower there the front. I didn't plan it that way, it just happen. After years of being that way I still don't know if I like it or not. Its not much. Most stock 66 mustangs are that way after 25 years. I put new springs but I had to put lowing blocks on them. One day I might fix it.