How much mpg is lost running a mid-roof instead of high-rise pulling a van?

It makes a difference. Get the right tool for the job. Reality check here you're up against modern trucks pulling vans and reefers getting 8 and 9 mpg anymore. Difficult to compete with that and it doesn't really matter what your rates are because if you're pulling a box you've got competitors.

 

Maybe converting to 6x2 for better economy might be worth considering pending circumstances.

https://tcdocs.ingeniumcanada.org/s... Vehicle 6x2 Drive Knowledge Gap Briefing.PDF

 

Got a flat top t600 with a S60 engine. According to the dash monitor on it I’m getting about 7.7 mpg give or take. Would a wing help that much more? I pull a reefer and do both dry and wet usually hauling under 30k

 

OP pull a tank instead

 

Last ifta was 6.34 in the 93 mid roof. Light loads I easily get 7+ running 65-68

The 99 is a flat top with a big gap between the van and that's still usually right around 6.0-6.2 but at 65 it's at 1625-1650 rpm with 4.42 rears. If it had 4.17s instead it would probably do the same as the 93 if not a tad better since it's an electronic engine and not a mechanical like the 93

 

Do you not idle ever? I find some of these numbers hard to believe. Yeah on a good day with a light load I could get 6.8 with my C15 cat and 3:70's in a T600 KW with no roof fairing pulling a van, basically a midroof. Idled to stay comfortable. But reality with that truck was probably a 5.8 lifetime average. An average is ONE number. It doesn't vary. It aint a "well if I bobtail or if I just have 1 pallet in the box it does great". Most legal loads are in the 40,000 -45,000 lbs range. If you can't do 7mpg, or better, average on all miles at a minimum pulling 40k or 45k loads then you're losing money. That's a fact.

 

If you're replying to me I don't see how those numbers are hard to believe. I'm local I don't sleep in the truck and I only idle when I have to keep warm or to cool off. Most of my outbound loads are 7,000lb and my return loads are 25-40k.

That's tall 24.5 with 4.42 the optimal cruising rpm for the mack's are 1550-1650

 

So not a real world OTR or even regional sample then.

 

Just out and back. Usually around 350 miles a day

 

Lifetime average - pulling open deck, all over -

2001 T2000 with N14, 7.2

1995 379 with S60 and ICT sleeper 6.2

That’s tracked precisely, tank to tank, 4 seasons, all terrain.