Difference between the RAM 2500 and 3500.
i drive a 2500 every day. its a 92 cummins. rough riding rattle trap but it'll run for ever and haul anything you want especially with the granny 1st gear
single wheel one tons are nice if you drive more without the trailer or haul less than 15,000 lbs normally
also with dual wheels if one blows you can still roll down the road, a lot of semi guys don't like the super singles for that reason.
but with singles you get better MPG