I was looking into running 19.5 tires on my truck since I already had the rims. The problem I found was that there are not many choices for tire sizes. Most are around 32" tall and the tallest is a 8r-19.5 that is around 34" tall. 8.25-20 tires are just over 38" tall and 34" tires will probably look too small on your truck.
