Which truck has better fuel milege

Not enough information but t680 is the most aerodynamic.

That doesnt count for nothing, but it doesnt count for as much as you might think

Would need to know rear ends, typical speed, terrain, weight, trailer type, application local otr or coast to coast? Tire size

A lot of things will play into what makes sense.

Even more important, youve decided on leasing a truck, not owning it, the biggest thing affecting your profitability will be your lease contract not the truck or fuel mileage

 

How many MI. on each truck??

 

Are you leasing a truck from a dealership or a rental agency, or from a trucking company?

 

The better question is wether or not your a patient driver or an aggressive driver. The patient driver whom doesnt try to break the sound barrier or feel the need to do 80 mph will be getting the better fuel mileage.

If your buying new. Tell the dealer you want a fuel efficient truck over a muscle truck
That being said it will help if your not driving in the rockies.

 

What @lovesthedrive said. With the addition of if you are going to be driving mountains the displacement of the ISX and potential torque from it will have you slowing down less on every hill.

You will need to ballance fuel economy, power on the hills, and serviceability. Paccar you are limited by number of service points compared to the ISX.

 

This. Also paccar engines are a mixed bag. The engines themselves are rock solid.....the def system....less so. So better MPG but down more often and pretty sluggish. The new 2021 motors are pretty decent though by reputation.

On the flip slide when an ISX breaks they break break and typically its a huge repair with a lot of down time from experince. However, they also tend to go longer between breakdowns and are easier to get worked on.

Not had a detroit in years but the one fleet i was with that had them, they were all yard babys. Im told thats not typical but im still leery after watching 40 new trucks get sold off in 6 months because they couldnt stay up for more then a few weeks at a time.

Sorry hit send by mistake. #### phone....So you gotta take stuff like that into account. The T680 would likely be the best overall in terms of mileage if you baby it but the W900 and 389 are not going to be far behind. The T680 is also lighter on average then most W900s and 389s. There are expections but being say 1500-3000 pounds lighter depending on setup can make a HUGE diffrence in both earning potential and fuel savings.

 

Something like 45 % of the difference in fuel economy is attributed to the drivers habits.
If you get a perfectly spec’d truck and hammer down every where, you’ll do much worse than the wrong spec truck with a good driver.
The T680 has the better potential.

 

Automatics are putting out some ridiculous mpg. I had a 2015 Cummins getting over 8, then they did a software update and I was getting over 9.5. And then one of my students was given a 2016 Detroit that could get over 10.

 

Dont rule the new manuals out. This was going up 64 in VA with 47500 in my bucket. 79900 gross. Ive seen as high as 8.2 fully loaded. Love my 579......when its not got #### def issues.