Looking to buy, 2500 vs. 3500?

I am shopping for a long cargo van and I see both 2500 and 3500 models. I think I know the basic differences: 3500 has dual rear wheels, lower differential ratios, stiffer springs? What real world could I expect if I bought a 3500: lower mileage, slower cruising speeds, rougher ride, more road noise? What about reliability, upkeep costs? Thanks for any opinions. I normally wouldn't be heavily loaded, except for trips with three small dirt bikes and gear.

The 3500 doesn't inherently get less mileage, although they are frequently equipped with lower rear end gearing and that may have an effect. Also you probably can expect stiffer springs. Otherwise no significant difference in reliability or maintenance, other than two extra tires of course.

Basically you should get a 3500 if you need the capacity, and a 2500 if you don't. Add up your planned load and do the math (and add a 20% fudge factor because you always end up heaver than expected.)

The 3500 will be heavier and the extra tires add drag. So yes there is a mileage difference, but it may be too small to notice.

There is a slight weight difference in the two extra tires and heavy-duty suspension and brakes, but this and the extra tire drag alone shouldn't amount to much in terms of MPG. With a lower rear end gearing (if so equipped, and 3500's usually are) you will be spinning a few hundred extra rpm at any given road speed so that might cause a slight mileage hit.

The lower gearing is greatly compounded by the 15" wheels on the T1N 3500 compared to the higher gearing and 16" wheels on most 2500's.

Gary