What is the best fuel mileage truck/engine combination?

dang ya beat me to it.

 

YEP. You gotta wanna get up in the mornin' and get behind that wheel every day - for many, many, many days. If you don't love it the 1st day you will usually hate it pretty soon! Balance comfort, mileage, power, quality and pride in ownership and you'll rarely get up and say "oh hell, I gotta drive this #$&^%& truck again today", and when the payments come due......

 

Friends don't let friends drive Freightshakers

 

I had a 98 Freightliner Classic 500det super10 and I think 3.70 rears pulling 53' dry van. My quarterly IFTA would be as high as 7.1 mpg and as low as 6.4mpg. That includes idle time, which I seldom did. Keep in mind I seldom drove over 60mph. Once in a blue moon I would have to keep it at 75mph but then sometimes I would run coast to coast at 55mph. I ran all 48 states with a average load being probably around 40,000lbs in the wagon. Very few loads were below 35k, but like wise very few loads were above 45k. Driving in the summer months east of the Rockies my fuel mileage would be as high 7.8mpg, but that would drop off to 5.8 hauling loads across the Rockies in the winter. I like a big hood truck because they are easy to service and do good inspections on. You can easily get to most componants without removing other componants to get to it, and there is plenty of light underneath the truck if you do your own lube jobs. Due to the geometry with a longer wheelbase, you get a smoother ride, and less likely to get sideways or jackknife in bad weather. The bad thing is going across New Mexico on a windy day you will definitly get dragged down. The wind drag is constant and expotential <(don't know if I spelled the right) as speed increases, so if you plan running fast, that's something to consider. The other bad thing about the big hoods is there is more wind noise. The sloped hood trucks won't be as loud, have less drag when your fighting the winds in Wyoming or New Mexico, and over all get slightly better fuel mileage. The down side is that the sideskirts get beat up easily (if you have them on) they are pain to work on or service. They hard to keep the frames rails clean and rust free because they are tucked in. I may be wrong but I don't think they hold thier valve as high as a classic style truck. As stated before, keep the tires inflated, keep the trailer tucked up to the truck, and I personaly think the best thing you can do is disipline that right foot.

 

I have a 12.7L Detroit with 13 speed tranny and 3.55 rear end gears and low pro 22.5. Final drive ratio on tranny is .87 and 12th gear is 1 to 1. I run I-20 from Dallas, Tx to Louisiana speed limit is 75mph. At 65mph I’m running 1700rpm. 70 mph is 1800rpm. If I changed my rear end ratio to 2.93 would that lower my rpm? Will I still have enough pull power to pull a few hills?

 

Swift uses to use a lot of 9spd trans. Some of them can be converted to 13spd. They bought them just for that purpose. They know many o/o would rather have 13

 

Lots of different opinions. Have a friend doing a lease with a T680 Paccar its has a 10speed 3.23 geared rears he avg. 8 at 63mph. With a apu on the trk his company pays 400.00 fuel bonus every qtr. He is always top 5 in fleet last 3yrs. So that in itself speaks for itself. But if he is heavy pulling big hills that drops to 7.3 . However it doesnt take alot for him to recover and get his mileage back up

 

It would drop you almost 300 rpms. Going to 11R22.5 would save a 100 rpms. You would still have power to pull but you will probably need to downshift sooner.