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OlympicFox · 11-15-2021, 09:11 PM

I learned a long time ago that truck manufacturers publish the highest capacity ratings they can get away with because those numbers sell trucks. Unfortunately, those ratings are not as simple as the ads for 1/2 trucks suggest.

At the other end of the equation, the RV makers usually minimize certain specs because they've learned that sells RVs. For example, RVs almost always include a number which infers its length, however the actual length is typically 3 feet or so longer. It's easier to sell the wife on the idea of a 34' 5th wheel than a 37 footer. Another number that can be misleading is the pin box weight (or tongue), especially on something like a toy hauler with a high load capacity. My experience is that the pin box will tip the scales at around 20% on a properly loaded 5th wheel (or 14% on a travel trailer).

Spec'ing a tow vehicle such that something like the engine is downgraded to improve the weight capacity specs is a short trip to an unpleasant tow experience.

7.3L gas specs. 430 HP at 5,500 RPM, 475 ft lbs torque at 4,000 RPM. Frankly I wouldn't want to have to listen to the gasser hitting 4,000 plus RPM in traffic just to get rolling or turning an extra 300 at steady 60 MPH cruise, or the 3+ gears it would have to drop to pull a grade. The diesel generally cruises at peak torque RPM or less, so when it hits a grade, the engine is in peak torque, or the torque actually improves as the engine slows a bit. OTOH, the gasser cruises at around 50% of peak torque RPM, so when more torque is needed, it MUST come from the "torque multiplier" - the transmission. Since the gasser makes less than half the torque of my Cummins while the RPM is twice as high, the gasser must use low gears far and away more often to get the job done. It has the horse power to go up the hill OK, but it will have to scream to do it.

I'd been towing our 11# 5th wheel with our 2010 Ram 3500 6.7 Cummins for years. Piece of cake and very pleasant, even in the mountains. Then we bought an Excel 5th wheel that weighed several thousand more, but was still within spec for the Ram. Fine on the flats, but oh-so slow in the mountains. I don't like puttering in the slow lane at 30-35 in 2nd gear.

FWIW, two years ago we traded the 2010 Ram for the new Gen 4.5 2019 Ram. The dealer gave me 55% of what I paid new with 160K miles on the clock. My hunch is that the value of the gas 4x2 wouldn't come close to that kind of value down the road.

11-15-2021, 09:11 PM	#6
OlympicFox Junior Member Join Date: Nov 2021 Posts: 8	I learned a long time ago that truck manufacturers publish the highest capacity ratings they can get away with because those numbers sell trucks. Unfortunately, those ratings are not as simple as the ads for 1/2 trucks suggest. At the other end of the equation, the RV makers usually minimize certain specs because they've learned that sells RVs. For example, RVs almost always include a number which infers its length, however the actual length is typically 3 feet or so longer. It's easier to sell the wife on the idea of a 34' 5th wheel than a 37 footer. Another number that can be misleading is the pin box weight (or tongue), especially on something like a toy hauler with a high load capacity. My experience is that the pin box will tip the scales at around 20% on a properly loaded 5th wheel (or 14% on a travel trailer). Spec'ing a tow vehicle such that something like the engine is downgraded to improve the weight capacity specs is a short trip to an unpleasant tow experience. 7.3L gas specs. 430 HP at 5,500 RPM, 475 ft lbs torque at 4,000 RPM. Frankly I wouldn't want to have to listen to the gasser hitting 4,000 plus RPM in traffic just to get rolling or turning an extra 300 at steady 60 MPH cruise, or the 3+ gears it would have to drop to pull a grade. The diesel generally cruises at peak torque RPM or less, so when it hits a grade, the engine is in peak torque, or the torque actually improves as the engine slows a bit. OTOH, the gasser cruises at around 50% of peak torque RPM, so when more torque is needed, it MUST come from the "torque multiplier" - the transmission. Since the gasser makes less than half the torque of my Cummins while the RPM is twice as high, the gasser must use low gears far and away more often to get the job done. It has the horse power to go up the hill OK, but it will have to scream to do it. I'd been towing our 11# 5th wheel with our 2010 Ram 3500 6.7 Cummins for years. Piece of cake and very pleasant, even in the mountains. Then we bought an Excel 5th wheel that weighed several thousand more, but was still within spec for the Ram. Fine on the flats, but oh-so slow in the mountains. I don't like puttering in the slow lane at 30-35 in 2nd gear. FWIW, two years ago we traded the 2010 Ram for the new Gen 4.5 2019 Ram. The dealer gave me 55% of what I paid new with 160K miles on the clock. My hunch is that the value of the gas 4x2 wouldn't come close to that kind of value down the road.