Ok I did some searching on here and I couldn't find anything about this maybe I just missed it but I figured it wouldn't hurt to ask in a new thread.

I was just wondering when pulling a flatbed does it really matter if you have a flattop sleeper or a big studio sleeper? I am asking in a sense of like gas mileage and aerodynamics. I know a flattop isn't the best choice when pulling a reefer due to the difference in heights from the top of the sleeper to the top of the trailer, but does having a certain kind of sleeper when pulling a flatbed help or is a flattop just as good as a big studio sleeper????

Obviously, a flatbed load can reach the same 13'6" height as a reefer, so at first glance, it would seem that the condo style tractor would work for it. However, if we study the aerodynamics a little bit further, we will probably come up with a somewhat different answer.

The tall condo style tractor with cab extenders works well as long as you can keep the front of the trailer located within 24-30" of the back of the cab. Once you get beyond that point, the air flowing over the top of the cab falls off into the gap betweeen the truck and the trailer, and you lose the benefits of the taller cab. What you want to achieve is called "laminar" air flow, which basically means that it remains uninterrupted as it flows up over the tractor and down the llength of the trailer. if the airflow falls into the gap between the truck and trailer, it "swirls" and becomes turbulent, and that adds to the drag of the truck and trailer.

Most flatbeds are designed now without full headboards, relying on a tractor mounted headache rack. They are set back from the tractor more than the 30', and this allows you to haul some over dimensional loads if needed, making use of the space between the tractor and the front of the trailer. Because of this longer gap, even when loaded to full height, you don't receive the benefits of full height condo. And, any time you are running empty, you are pushing 13' of fibreglass through the air, without it returning any aero benefits to you.

So, if I were to choose a tractor for pulling a flatbed, I would tend to look towards a mid roof tractor, and when buying, if it was condo height, I would only want one with a removable air shield. This way, you have the option of going out to pull a van, and all you have to do is put about a dozen bolts in place and you have your condo aerodynamics back. A mid roof will provide you with almost the same interior space as a full condo, since you really don't make effective use of the upper 3 foot anyhow. It's also easier for your trucks environmental system to cool or heat the smaller interior, since you aren't having to cool that upper three foot of space, nor is it sitting there soaking up sunlight during the day.

For pulling a flatbed, grossing 80k, my general specs would be as thus:

Aero Tractor, any brand, 370-430 hp, preferably a smaller motor like ISM or C-13 Cat, 10-13 Speed, mid roof sleeper, 48-72", 220-230 wb'

For pulling a flatbed, grossing 80k, my general specs would be as thus:

Aero Tractor, any brand, 370-430 hp, preferably a smaller motor like ISM or C-13 Cat, 10-13 Speed, mid roof sleeper, 48-72", 220-230 wb'[/quote]
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As a deck hauler myself, I agree with the midroof sleeper, but have to respectfully disagree on his specs. For myself, I haul anything from standard dimensional freight to 83,000 lbs overweight as well as oversize. For myself, I would specify a tractor with a set back front axle (there is just no way to maximize your steering weight allowance with a W900 or a 379), a 242" wheelbase with cargo boxes built into the drone deck, at least a 475 HP engine geared to an Eaton Fuller 18 double over running back to a set of Rockwell 44,000 lbs rear ends with 3.85 / 1 ratios set up with Detroit lockers, and matched 135 gallon tanks.

Well, I heartily confess that I tend to believe in the "lighter is better' theory, and would specify a truck that would be as light as possible for the job. And if you are going to haul overweight loads and over dimensional, then you may have a reason for the specs you set. But for general flatbed work, I would stick with what I listed.

The smaller engine removes about 800 pounds from the equation, and the engines are available in hp ranges well suited to hauling 80k loads. I can see absolutely no load except for heavy stuff where I would ever look at an 18 speed trans of any type. I always keep in mind the future and the possibility that I will have to replace a transmission at some point in the future. If I do, I can have a rebuilt 10 or 13 speed put in with a new clutch for about 3000. If I have to have an 18 speed installed, figure that about 6000 dollars are going away in the process. they are not cheap to replace.

As for the hp, properly geared. a 430 hp engine will take you anywhere in the country you need to go. We use to haul loads all day long with 238 hp and 290 hp engines, and if you had a 335 you were the king of the road. A 370-430 hp engine is a good choice for fuel mileage, and will be about as reasonable to overhaul as any diesel engine can be. Get up into the higher hp ranges, the price for repairs or rebuilds climbs drastically.

As for the 44k rear ends, again, unless you plan on doing heavy haul, there is nothing to be gained out of having them and a standard set of 38k or so rears will do the job just fine. And as far as the wheelbase is concerned, if you like a longer truck, then fine, but I want to keep the length down for ease of getting it around in town. I drive a 210" tractor, and sometimes wish I had a shorter one for some work.

My goal in general flatbed specs is to keep the truck light enough that it can be hooked to a light weight composite flatbed and be able to scale 50k on the deck. You may not haul that much every time, but it's always nice to have the ability to do so when needed.

Everyone has their own choices, and their own prejudices in selecting machinery. I freely admit that I believe in light weight aero type tractors, and I don't think I have ever once bothered to take a look inside of a "classic" styled truck. they have no interest to me, because I can't envision paying out of pocket for the fuel needed to push that air aside. I lean towards making money with a truck, not just spending it to placate my ego.

Thanks for the good info, I am planning on going O/O in the future and want to haul flattbed or step deck. I have to admit I'm a sucker for the flattop sleepers especially the 379's even though they get much lower MPG than a more areo styled truck...I want a truck to look good but I will also be doing it to make money like you said burky. Any suggestions on a good aero styled truck with a flattop or would a flattop sleeper not be a good choice at all??

Again thanks for the great advice!!

I don;t like to suggest a specific truck model or brand to someone, because your needs may differ from mine, and your preferences may be different. Instead, I prefer that you find a couple of models that will do the job and select among them. We get a lot of people saying that you should buy a clone of whatever they drive, and the only reason is that they like their truck, regardless of whether or not it fits your needs. I tend to refer to them as the "300/600/900 Club" because they want you to buy a 300" wb, 600 hp, W-900, solely because they have one.

My suggestion as far as brands go may sound a little bit off the wall, but if you arre looking at an aero model, I don't really feel that there is a massive difference from one brand to another. They can all be specced so close to one another that there is no huge performance difference, so here is what i would do if I were you and looking. Find a model from each manufacturer that fits your needs, and look them over closely. Set down a list of the specs you want in a truck, then start looking through the truck paper and see how many you find with the specs you desire.

Eventually, you will find a couple of models that will meet your needs and are available in reasonable quantity, and priced in the price range that you are looking at. Then, sit in them, reach out and feel switches, look at gauges, and spend some time in the interior. You will find one or two models that will rise to the top of your list.

Spend a lot of time looking at the interior, because that is where you will be spending your time and where you will be for 120k mileas year, as well as sleeping at night. Litle things mean a lot when you are going to spend much of the following year in a truck.

In my case, for the work I do, I have four favorite brands that I have selected for when I buy a truck in the future. And over time, one of those brands brought out a different model, and the truck was improved enough to jump from 4th to a tie for first.

It's a matter of what you are going to do with the truck, and how you want to use it.

By the way, I currently drive a flat top sleeper, and get by just fine in it. I use my sleeper solely for sleeping and break time, so I don't need a a huge amount of space. And weight means a lot to me, so a smaller lighter sleeper is just fine.

Thanks for all of the great info...I love this forum due to the large amount of knowledge that people are willing to share. I will keep all of this in mind when it comes time to buy my truck. Again thanks for hte awesome info, also just wondering what kind of truck do you drive?? and if anybody else has anything to share it would be greatly appreciated!!

I'm currently driving a 2006 Mack Vision, 48" flattop sleeper, 209" wb, 10 speed Mack trans, 380/410 hp engine. 201k miles on it so far.

The number means 380 hp on the throttle, and when the cruise is engaged, I have 410 hp available. Good truck, gets about 5.75 mpg pulling the tanks that I do, will bring in over 7 mpg on a van trailer.

I'm running a Kenworth T800 with the 63" midroof integral. With the Cummins N14 and the specs from my earlier post, I am averaging 6.2 mpg. The truck is a little heavy at 23,200 lbs but that includes my headache rack, my chains and boomers, 1 full set of lumber tarps, 4 LTL tarps, a smoke tarp, my toolbox with all my steel corners and softeners, and my steel coil bunks.

My Mack, full of 200 gallons of fuel, weighs in right at 18,000 pounds. I don't carry all of the items he does, but I do have a truck unloading blower mounted on it that adds about 500+ pounds to the equation.