Radials were the best thing I did to improve the handling of my truck. Stock rims do measure 4.5 inches and the tire shop will likely tell you it can't be done, but it can. IMO 16's sometimes look balooned on 4.5 inch rims. They may also tell you that you need tubes, but I haven't lost air for years at a time. I didn't use 16 inch rims, but went with later Task Force 15 inch rims and 7.50 or 7.00' by 15's. These rims measure 5.5 wide and take the stock caps fine. Another option is to have some rims made or modified, I have heard of this being done for prices that are reasonable.
