(Part 2)
The Weight
I’m not going to explain all the weight terminology, but you can find plenty of info on that elsewhere on the web if you need it. My goal with the weights was to ensure that I was within the gross weight limit of the truck, the gross weight limit of the trailer, the gross combined weight of the entire rig, and finally to see if the weight distribution hitch was doing its job of putting weight back on the trailer axle and front axle of the truck.
I used the Weigh My Truck app from CAT scales and here’s how I did my weights. First, I pulled on to the scales with my entire rig. This gave me a weight for the front truck axle, the rear truck axle, the trailer axles, and the entire rig. Next, I pulled forward and put the tongue jack on the first scale plate and the trailer axle on the second scale plate. I disconnected the truck from the trailer and pulled the truck clear of the scale. This weigh gave me the tongue weight and the gross weight of the trailer. Finally, I moved the trailer off the scales, disconnected it, and ran my truck through alone to get a baseline weight for the front and rear axles. I wish I could have done my empty truck too, but there were no scales near my home in Pagosa.
Here are the weights I got, hopefully organized in a way that makes sense. I’ve started with the limits, then given the truck or trailer alone, and finally the combined weights. All combined weights are with weight distribution engaged.
Truck Front Axle
Limit: 5200 lbs. Loaded Truck: 3640 lbs. Truck and Trailer: 3600 lbs.
Truck Rear Axle
Limit: 6000 lbs. Loaded Truck: 3440 lbs. Truck and Trailer: 4040 lbs.
Truck Gross Weight
Limit: 8800 lbs. Loaded Truck: 7080 lbs. Truck and Trailer: 7640 lbs.
Trailer
Limit: 7000 lbs. Trailer Axles Alone: 5360 lbs. Trailer Axles with Truck: 5740 lbs.
Tongue Weight: 920 lbs. Trailer Gross Weight: 6280 lbs. Tongue Percentage: 14.6%
Combined Gross Weight
Limit: 15,000 lbs. Actual: 13,380 lbs.
Now, I could really geek out on these numbers, but let me just point out what I consider the most important facts. First, note that everything is well within the limits. That’s nice! Second, note that with the weight distribution I’ve only “lost” 40 pounds off my front axle. I’ll explain the weight distribution in a bit more detail next.
With the trailer on the truck and the weight distribution engaged the rear axle of the truck was 600 pounds heavier. 40 pounds of that came from the front axle, which means 560 pounds came from the trailer tongue. The trailer axles gained 380 pounds, which also comes from the tongue weight. Now, if you add that up, 560 and 380, you’ll get to 940 pounds, 20 more than the actual tongue weight of trailer. Where does the extra 20 pounds come from? Wish I could say for sure, but I can only guess…regardless I was quite happy with the results. They confirmed that the trailer’s tongue weight was being distributed between the trailer axles and the rear axle of the truck and that I wasn’t loosing much on the front end.
Finally, remember my concern about the 800 pound tongue limit on the hitch? Well, note that the tongue weight with weight distribution engaged was only 560 pounds, even though the trailer’s tongue weight was 920 pounds. This confirms that even with a trailer tongue weight of 15% the hitch tongue weight was well within its 800 pound limit. I guess those engineers knew what they were doing!
The only other thing I wish I did was run the truck and trailer through without the weight distribution engaged. Could have added some more numbers to crunch for fun, however, I was pressed for time and I could see that I was well within all the limits I really cared about. The only adjustment I ended up making was moving a little weight from the front of the trailer to the back. I decided to do this to bring the trailer tongue weight closer to the middle of the 10-15% range and because I felt the trailer was riding a little nose low.
The Ride
Okay, we’ve explored the numbers and theories, but how did it ride? Well, again I have to admit my lack of experience, but I’d say it rode great. During the trip up we had all kinds of conditions; snow, ice, winds, windy roads, mountain driving, semis, etc. While I could certainly tell I was pulling a trailer I never felt like it was out of my control and that’s what I was looking for.
The Drive
Driving Style and Power
I suppose before talking gas mileage I should mention my driving style. I’m not a fast driver. That being said, there is no way I could even come close to the speed limits on the interstate anyway! Making my way north through Colorado, Wyoming, and Montana I might have passed one or two vehicles in total. Mostly I was happy if I could keep things moving between 55 and 65 and that was generally in the 2000 to 2500 RPM range. Definitely had my moments of going much slower on steep grades and occasionally I might even maintain 70 at about 2200 RPM on the flats.
In the end, I would say the 5.7 was a bit underpowered for my total combined weight and the driving environment (mountains). After my experience I think a more powerful (bigger) engine might have been more efficient at 60-65 MPH and probably would go faster too. I guess I could have revved it up quite a bit more to get 70 or 75 out of the truck, but I think that would have really killed the gas mileage and put extra stress on the engine.
Gas Mileage
So, what was the gas mileage? The best I got was 10.7, the worst was 7.8, and the average over the trip was 9.1 MPG. I had been hoping for 10 average, didn’t quite get there. I mentioned in Powerplant above that my original theory was that I would get better mileage with a smaller displacement V8 (5.7 vs 6.4 or 6.2 in a Ford). Now I’m pretty sure the 5.7 had to work so much harder, even at a moderate speed, that in the end it killed any efficiency gained from its small displacement.
This was loosely verified by a fella I talked to who has owned several of the 5.7 and 6.4 Rams for his company’s work trucks. He confirmed that the 6.4 gets slightly better mileage on average. Makes me wonder if Ford’s V10 (an option I had also considered) would have done comparably well even with the extra cylinders?
Tow/Haul Mode On vs Off?
Also relevant to gas mileage I suppose… After driving the first day with the Tow/Haul mode on I decided to try a day having it off. There it remained for the majority of the trip. Why? Well I simply liked the way it drove better. With Tow/Haul on it keeps the RPM high (presumably in the power band) and even going gently downhill it really liked to stay in lower gears. I personally liked having it drop into the O/D gear whenever possible. I had no issues with hunting or feeling like it was working harder with the Tow/Haul mode off either. The one place I did use it was for longer descents on steep grades. Other times I’d just manually shift down to 2nd gear.
How did it affect gas mileage? Seems like it should have been better with Tow/Haul off, but it didn’t seem to improve much. Wish I could give a better answer, but the conditions of the road and weather changed so much throughout the trip the mileage was never very predictable anyway. For this reason, I don’t think I can make a fair comparison.
One Snafu
If you made it this far…good for you! I thought I’d have some major takeaways but other than what is sprinkled throughout the text I really do not. I did have one major snafu that in reality could have been a hundred times worse. About an hour out of Fort Nelson I pulled over at a rest stop (which are really just pull offs for most of the route), got out of the truck, and immediately heard air coming from one of the trailer tires. Must have run something over pulling in…no worries, I have a spare.
The day was early, figured we’d have the spare on in 30 minutes, hit Fort Nelson early enough to get it repaired, and then be on the road in the morning as planned. All was going smooth until I went to mount the spare and realized the lug pattern on the wheel didn’t match the axle!! That was disappointing. It was a brand new spare that was purchased with the trailer from the dealer by the previous owner. They must have grabbed the wrong one and without holding it up to the axle or measuring you’d definitely never know it wasn’t a match.
After a few cuss words we loaded the tire in my wife’s Saturn and drove it to Fort Nelson to be patched. Then we drove it back out to the truck and trailer, mounted it up, and went back to town. Cost us a couple hours, but could have been much worse. I hoped they would have a spare to swap with me, but no luck. From Fort Nelson the route gets much more remote, not something I really wanted to tackle with no spare. The tire guys had a good suggestion though, just pick up a small 12V air compressor and tire patch kit from Napa. So that became the backup and thankfully it wasn’t needed for the rest of the trip.
Well, that was my trip. Thanks to all those that gave me advice and I’m happy to say other than my flat it was pretty uneventful. Safe travels out there!
mikeruSuper Moderator