Condo vs mid roof mpg differnce

Here's some data: http://www.c2es.org/federal/executive/vehicle-standards

 

Do you haul steel? Wont you be better off with a midroof? I mean arent some if not most of the old steel mills in the midwest to low for a condo?

 

When I talked to the Western Star factory rep about my truck he did some research for me. He figured out that they did not do any wind tunnel testing to see the difference between mid roof and condo on the 4900, but he found the test for the Cascadia and it showed about 3% improvement for the truck.
I have the high roof and to add the fairing to make it an ultra high roof would cost about $6000.00 with a new fairing, paint and install.

 

there is no scientific data. each model year changes.

i pull a flat, and have averaged anywhere from 5.2 to 5.7. FL's, petes, kw's. isx's 450 and 475 and d60 400 horse and dd15 450 and now 515.
all the trucks were mid roofs, except the 12 FL which had a spoiler on top. THAT truck got the best at 5.7.

i'm now in a 16 full sized condo FL. dd15 engine. it gets the best mileage. at 7.0. with a van or curtain trailer it'll hit 7.5.
the second best truck was the d60 and that was in a 96 t600. with a super10 junkie. it averaged 6.2.

all my running has been the western mountains. you guys running the flat land will get much better.

midroofs are nice, they don't take the wind as much. but my first full sized is getting the best.

the push seems to be the automatic transmissions getting better. but i have a 13. and i'm getting just as good as the rest of our fleet which all have automatics.

 

It would vary depending on the freight on the flat bed -- without an accepted "standard" flatbed load, every test would have different results

 

Source, please...

 

Freightliner (at MATS). The elongated & more pointed upper shape, like the roof of the prostar & 9400, moves air more efficiently than the blunt leading edge on the Condo.

 

one of these days, they'll figure out a way to eliminate that big air scoop hitting the radiator.

probably see an extra 2 miles per gallon with that gone.

 

I had a 2006 Century with a 450 Mercedes. When I bought it new it was just a flat-roof and I had the dealer put on a full fairing before I took delivery. Initially I hauled dry van. Later on I took the fairing off as I did grain hauling for a few years and needed the clearance to get into some of the older elevators.
I went back to dry van but couldn't get the fairing out of the back yard in the winter. Come spring time I finally got the fairing back on and immediately saw a 0.6 mpg increase. I keep track of my fuel economy religiously. So I'm guessing a mid-roof would see maybe a 0.3 mpg increase seeing as there is less of a height difference than mine had.