Did my first hard pull with mods listed, Smarty on level 3. Pulled in Tow/Haul mode the whole way. Weighed truck and camper at Flying J at 17,400 pounds. Ran her hard avg 75 mph, even up big grades never got below 70 mph, temps would just touch the 1300 degree mark with probe in the manifold but could just feather the pedal and keep it between 1100-1200 on a big hill. Mileage was only 9 mpg but at over 17K and running that speed does this sound normal for mileage, I was hoping for more but I know thats heavy and fast so any feedback is welcome. Other than slow down

 

To me that sounds good for mileage. My truck is stock and I get about 10.3 running 65 mph weighing about the same as you do. I slowed down to 58 to 60 mph and my mileage has increased to 13.5.

I myself am going to start running at 58 to 60 mph because I want the better mileage and I am not in such a huge hurry as I used to be.

 

Thats a big increase in mpg for just slowin down a little. The right lane is usually less crowded anyway.

 

So (assuming you've got the 48RE) when you were pulling hard grades at 70mph and hitting ~1300°, were you in 3rd gear and turning about 3000 rpm?

If so, just for comparison, that's about how my SO (w/mods) pulls a 10,500 lb loaded toy hauler up 4-6% grades. I'll get about 10-11mpg at 70-75mph on the interstate.

 

I like the idea of slowing down. Done it for years. I like to drive so it gives me more time behind the wheel. and to drink while I'm driving.

 

I am all about slowing down and enjoying the trip. ST trailer tires are only rated for 65 mph. If you air them up a bit over max, you are supposed to be able to get 70 mph out of them. It only takes a couple of RV trailer tire blowouts to teach you that slower is better. Both of my blowouts on toyhaulers were at 60 mph, and that was fast enough for me.

Best Regards, Sky-Dogg

 

9 MPG @ 17,000 lbs @ 75 MPH sounds pretty good to me.

 

I drive a 98 quad 2wd 2500 auto 150k on the clock and get 19.2 empty and 13.7 loaded truck,truck hit scales at 7100 and my deckover gooseneck weighs 3500 I usually haul my loader weighing 9600 lbs,putting me over 20k lbs truck is stock except for k&n intake and 4"dynomax exhaust as well I stay at about 60 mph and drive in NH & VT so its hilly

 

I've been pulling cars with my 2003 Ram 1500 4.7 and an aluminum trailer (never over 7,000 pounds being towed, maybe 6500 for the truck and gear in it). If I get 10mpg loaded at 65-70mph I consider that pretty good. I haven't done any towing with the diesel yet, but with that truck, MPG is almost entirely determined by aerodynamics and wind, weight is barely a factor, amazingly. By slowing down, the effect on MPG is exponentially less. Just earlier today I was pulling my trailer into a strong wind, with the trailer empty (it's only like 1400 pounds empty) and getting about 11mpg at 70mph. Slowing down to 55mph it shot up to 14-15mpg, which is barely less than the truck gets on its own at 70mph.

Remember, the national speed limit was lowered to 55mph to save fuel, not for safety reasons. You will always get WAY better mileage slowing down. Even 65mph instead of 70mph will save a lot.