RGN Setup

What tires are you running? Brand and model. Are you asking about fuel economy?

 

My opinion?

1. lose the Volvo. That D12 isn't going to get any better. They're notorious for getting crappy mileage, except in the best of condition, which RGN ain't.

2. Are you looking for new or a used truck to potentially replace the Volvo? If used, I'd say a higher HP (500+) Cat or ISX with 1850 or more torque w/ a 13 or 18 and 3.36's (with a Cat) or 3.55's (with an ISX)
If new, my thought would still be a Cummins with the same specs, just specifying Michelin XOne XDA energy drives.

One other thought... Are they both pulling identical trailers? Just wondering if the two trucks ever swap those RGN's and if so, and difference in fuel economy when they do.

 

if buying new buy a glider kit ....save 25% no fet and get a reman pre emissions engine and you will be seeing near or above 7 mpg

 

What does their idle time look like?

 

I just had some work done on my truck at the KW dealership near me, and there were at least 6 T700's w/ the Paccar engine in them sitting in the shop. All the same company, all the same problems, and all recurring ones at that. This according to the tech who was working on my truck. His comment was that he wouldn't even think of getting a truck with the Paccar motor right now. Too many bugs still needing to be worked out.
I'd definitely stay with the Cummins rather than the Paccar.

I agree with the comment about a glider kit. Spec'd out right, you'll get a new truck, for all intents & purposes, and not have any emissions crap to deal with, as well as getting much better mileage & not having to pay FET.

As the saying goes, "You Mileage May Vary". Spec'd right, and most importantly driven right, I would say mid 6's to possibly low 7's are a real possibility with the CAT. Mr. Haney would probably have a better idea of just exactly what kind of MPG you could expect with a particular Cat setup.

I stated 3.36 with the Cat & 3.55 with the ISX because of the individual engines' "personalities". All else being equal is the setup (tire size, gross weight, which transmission is being run, etc.), the Cat tends to be more of a grunt motor (lower RPM torque), and will return better MPG's when shifted and cruised at a lower RPM.
The ISX will return just as good MPG numbers, if not better in some cases, but returns better MPG numbers when it's shifted a little higher and cruised around 1450 RPM or so. When it's got a heavier load on it, it likes to talk back when shifted too low or lugged.

And yes, the XOne XDA Energy tires will make a noticeable difference in fuel economy. They have just about the best rolling resistance available, and they are lighter than any dual setup. In addition, they will also decrease your unsprung weight, which while it won't really help MPG's, it does make for a better ride, and less punishment to the suspension components.

 

pulling a rgn with 3.36 gears? (have you ever tried that) my mack pulling the lowboy low 7's high 6's in the summer winter i lose about 1mpg I know some guys getting very good milage high 6's grossing 100k or better with mp8's good luck getting mileage out of the newer Cats and Detroits pulling a rgn