Those tires can provide some cushion. I worked at an elevator this late fall for an employment experience in college. The large terragators that run those tires are Extremly heavy. That truck wouldnt weigh those tires down much if at all. Therefore is gonna bounce like a Biatch if he ever trys to get air. Also Terragators even have spring packs, the rears(where the bulk of the weight is put on) are about 1 foot and 4 or 5 inchs thick, but they do have spring packs.
and the tractors that have solid suspension like that seldom go over 20 MPH and thats only on road surface. When its a real rough ride its usually around 6 mph.
It looks to me thats just a show truck and it probably have the box loaded full of amps and subs.