I had the same problem with my GMC and 5er. I had the 3" axle
lift, went with ST215/75-14R tires
, and added 100lbs to the rear of my truck-bed. The 100lbs was flat steel plates (cut to fit at a machine shop) and resulted in lowering the truck-bed 1". Pros and cons about the plates, but it worked for me as I have my 5" clearance.