What makes the 3500 different from 2500 both SRW towing capacity

[Fowlthing]

I am pulling a 40 foot fifth wheel, currently with a F350 SRW. What will I get with 3500 , or I might say why is towing capacity higher. than the 2500.. SRW

 

[CG2742]

2500 has coil springs in the rear. The 3500 has leaf springs. Which are better for towing heavy. I believe they have the same axle unless you have a drw

 

[MADDOG]

Different springs = higher payload

 

[dhay13]

Not to mention you will be way overloaded with a 2500 Cummins with your 40' 5th wheel. Your payload will be in the neighborhood of 2100lbs and you probably have at least 2500-3000lbs pin weight