Freightliner Cascadia Evolution horrible fuel millage

Weird. Our evo has a lifetime average of 8.5mpg@106k miles with a 10 speed governed & drove at 62 all 48states irregular route OTR with about 70% of loads 75k-80k gross, 15% avg deadhead miles.
This is with all Michelin xOne steers & super singles, drive wheel covers, 99% trailers with skirts, 75% trailers with tails, APU fuel, bunk heater fuel, & idling all inclusive.

Don't know final gear ratio but it runs at exactly 1300-1306rpm @ 62mph in 10th(OD.)

Your auto should be even better (especially on regular coast to coast trips) but I did notice fuel milage picked up significantly at around 95k miles or so, which I attribute to the break in of sorts.

Most importantly, are you inflating & maintaining both tractor & trailer tires at proper air pressures while tires are cold?

Checked the amount of idle time they run for?
That is about 1gal/hr right there on average.

Along with that, idling will clog your DPF filter real quick(doesn't do any favors to the EGR either & just adds to the chances of extra maintenance down the road) & regen does not restore things to new condition after continuous fouling; it is a slow death sentence on any 2007+ year truck to idle regularly & even more so with the DEF model peculiarities & complications.

Also recently learned that
If the trucks already have some miles on them, might want to get the DPF filters cleaned. (or at least inspected)
Also make sure the intake air flow sensors & intake air filter are clean.

Overhead at around 250k isn't a bad idea as well.

Headwinds hurt no matter the aerodynamics & are hard to calculate for.

Are you sure trucks are not being run with the PDL accidentally left on?

Sure your drivers know to not drive tandem heavy?
That will kill mileage real quick in my experience.

Are you sliding 5th wheel to close tractor-trailer gap as much as possible? (steer weight providing of course.)

Have you made sure the cab extenders are flared out as far as they can go without obstructing trailer corners? (there are screws & multiple mounting positions on the giant plastic mounts securing them to sleeper.)

 

That is the funniest thing I have read in a while. You think your truck should be getting better then 6.5-7mpg?

Welcome to the real world.

Please step away from the truck stop lunch counter. Keep away from the super-truckers. Ignore the fleecers making it big at the mega. The BS never stops.

 

Just because you don't experience something doesn't mean it does not happen elsewhere to others.

Fundamental advancements of science were never made by people believed that things could never be any other way than they currently were or were perceived to be.

 

Tandem heavy?

 

Weight on tandems exceeds weight on drives.
Drags weight rather then carries weight, especially on hills & starting from dead stop.
Easy to tell when loaded this way, feels like you are carrying more weight then you actually are & has a significant effect on acceleration & fuel economy.

Also upsets entire truck balance & effectively raises center of gravity as higher weight concentration in one area during side loading suspension (curves/turns) has an greater mechanical & inertial advantage over same tire footprint combined with the "fishtailing" effect of multiplying force towards the rear of the trailer farthest away from initial steering input, ala doubles & triples.

Loading more weight on drives vs tandems also unbalances but does not have as much the same negative effects on fuel economy or stability.

Some instances, such as when needing maximum traction on ice, prefer maximum weight on steer & drives to maintain control of entire vehicle & tandems also benefits from less sudden/forceful inputs so tandems as far back as legally/weight limiting possible aids both these goals.

The optimal aim for traction, stability, fuel economy is for perfect weight balance on tractor & trailer but biasing toward more weight forward is preferred if not possible.

I do not know nor have any experience with spread axle trailers & how spreads affect the physics, but on 53' tandem trailers this all holds true.

 

I figured thats what was meant, I'm always trying to squeeze extra MPG out of my Evo. I try to keep as much weight off the back as I can if I cant get it balanced. I will say I pulled a near max gross (79920) the other day and naturally it was almost balanced perfectly, and pulled better than the load I had before, at 75K but most of it on the back.