Montana Owners Club - Keystone Montana 5th Wheel Forum - View Single Post

TimButterfield · 05-18-2012, 08:28 AM

Thanks for the concern. I researched the Ram 2500/3500 SRW difference quite a bit. The only difference between the two is an extra spring and 64 pounds. I have heard it explained this way. The 2500 is a 3500 SRW that has been de-rated for registration purposes (< 10K GVWR). Other than that spring, everything else, axles, frame, tires, etc. is the same between them. There is only a 200 pound difference in rear GAWR. That is why, with the Timbrens installed, I feel comfortable using the 3500 SRW ratings for my checks. I created a spreadsheet to check truck and trailer weights and rating numbers. I calculated available rear GAWR for the truck given base weight + hitch, gear, etc. I also calculated GVWR pin weight for the trailers using the same pin weight percentage as at empty. (I know the pin weight percentage can change with how it is loaded, but needed some base number for comparison.) While the truck rear GAWR could handle 3700 GVWR pin weight, it was too close for me. The 3400 has a larger cargo weight capacity, but allowed almost 400 pounds more cushion by comparison, partly due to lower pin weight percentage. Of course, I cannot know until loaded what actual pin weight is. For both your truck and mine, the tires are probably the limiting factor as they are load range E rated at about 3,000 each. (Reminds me of the Marathon vs G614 issue.) Or, are your truck tires rated for a higher capacity? If so, what do you have? (Thanks.) If this does become an issue, I can always upgrade the truck wheels/tires to something like the Rickson 19.5" wheels and higher rated tires. Depending on actual weights, I may need that if I decide to eventually add the generator.

05-18-2012, 08:28 AM	#8
TimButterfield Established Member Join Date: May 2012 Location: Des Plaines Posts: 17 M.O.C. #12495	Thanks for the concern. I researched the Ram 2500/3500 SRW difference quite a bit. The only difference between the two is an extra spring and 64 pounds. I have heard it explained this way. The 2500 is a 3500 SRW that has been de-rated for registration purposes (< 10K GVWR). Other than that spring, everything else, axles, frame, tires, etc. is the same between them. There is only a 200 pound difference in rear GAWR. That is why, with the Timbrens installed, I feel comfortable using the 3500 SRW ratings for my checks. I created a spreadsheet to check truck and trailer weights and rating numbers. I calculated available rear GAWR for the truck given base weight + hitch, gear, etc. I also calculated GVWR pin weight for the trailers using the same pin weight percentage as at empty. (I know the pin weight percentage can change with how it is loaded, but needed some base number for comparison.) While the truck rear GAWR could handle 3700 GVWR pin weight, it was too close for me. The 3400 has a larger cargo weight capacity, but allowed almost 400 pounds more cushion by comparison, partly due to lower pin weight percentage. Of course, I cannot know until loaded what actual pin weight is. For both your truck and mine, the tires are probably the limiting factor as they are load range E rated at about 3,000 each. (Reminds me of the Marathon vs G614 issue.) Or, are your truck tires rated for a higher capacity? If so, what do you have? (Thanks.) If this does become an issue, I can always upgrade the truck wheels/tires to something like the Rickson 19.5" wheels and higher rated tires. Depending on actual weights, I may need that if I decide to eventually add the generator.