Speed and Gearing Questions / Truck Selection

Discussion in 'Storage Trailer' started by Youngin thats Truckin, Jul 22, 2006.

  1. Youngin thats Truckin

    Youngin thats Truckin Bobtail Member

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    I'm gonna be pulling reefer, runnin mainly east of the mississippi river and texas and I'm all about the good fuel mileage, but unfortunately i'm not a gearhead. The first thing that comes to mind is a 13 speed with 293 rears and 430/470HP, where i can ride about 68 mph or so at about fourteen hundred, that'll produce some fuel mileage. but what happens on the hills when i've got 40,ooo in the box. so i guess my question is what specs do i need? should i go ahead and get a bigger rear end or will the 293's be ok?

    next question is what the difference in fuel milage between a classic and a columbia/centrury? is it that different? i'm approved to spend about 60, and i've been workin with selectTrucks, and am pleased with there service so far, but torn between comfort/looks/more expensive (classic) and better fuel mileage/better turning radius/more reliable (columbia).

    WHAT DO I DO???????

    THanks
    Blake
     
  2. Joethemechanic

    Joethemechanic Medium Load Member

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    I get a figure of about 73 mph with the ratio you mentioned, but being that I don't know the exact tire size I think we are close. without knowing what the torque and horsepower curves look like for your engine, I can't comment on what is going to happen when you hit a hill with 80,000 gvw.

    As far as the truck goes. To make money, cheaper and more reliable is always a safe bet.
     
  3. Burky

    Burky Road Train Member

    As far as the debate over aero vice classic, let me throw in some input. Had a budy of mine that ran a Classic (in fact still does), running the same routes and loads that I did with my previous CH613 Mack. The company always put out a quarterly report on our fuel mileage at the terminal. No matter what happened, he was always at the bottom of the list, usually a full mpg lower than the rest of the trucks. I typically ran 5.8-6.0, and he never once in 2 1/2 years broke over the 5 mpg mark.

    The Classic has air cleaners, exhaust stacks, a big flat grille, and a lot of other things that sit out in the airflow. And when you push the air out of the way and through the turbulence those things cause, it takes fuel to do it. Next time you are driving down the road at 68 mph, hold your hand up flat out the window and feel how much air hits it and how much pressure there is. Then look at how big an intake canister is, or an exhauist shield compared to your hand.

    So, I guess I pretty much make it clear which side of the aero vs classic debate I come in on. I want my truck to be a business tool that returns the most on my investment. I can buy toys for myself later on to satisfy my ego if I feel the need, but I make decisions about the truck strictly as a business decision. And that means that the less money I spend, the more money I get to keep.

    Second issue, you are looking at an awfully high speed for getting decent fuel mileage. I would look at setting the truck up with no more than a 65-66 top end, and then running it no more than about 58 loaded. When you are empty, you can run the higher speeds because you have shed the rolling resistance of 40k pounds, but speed makls a tremendous difference in yiur fuel mileage. And I am very much aware of the pressures in the reefer world to get it there as fast as possible, but running the lower speed is easier on the truck, easier on you, and much less likely to draw notice from law enforcement. The faster you go, the more fuel it takes to do it, and that means more money out of your pocket. And the amazing thing is that if you run about 58-60, you will arrive at almost the same time as you will if you drove faster. be smart, spend time actually driving vice making stops, and you make pretty decent time.


    Run these numbers for yourself and see what they do for you. If you run 120,000 miles a year, and get 5 mpg you have to buy 24,000 of fuel to do it at roughly 3 dollars a gallon. If you run the same distance at 6 mpg, you need to buy 20,000 gallons of fuel. At 3 dollars a gallon, that's a 12,000 dollar a year difference out of your pocket and bottom line for the luxury of having the classic styled truck. Own it 5 years, and you will spend at least 60,000 just on having those big stacks and grille.

    And don't get me wrong, I like the looks of Classic style trucks. I would kill to buy a 9900 IH when the time comes to buy a truck, but my business sense tells me not to do that. I'm just as capable as the next person of getting weak in the knees from a nice looking truck, but I do my business stuff with my head and not with my heart.

    In short, I would go with the most aero machine I could get, set the hp around 400-430 with a split power setting between the cruise and pedal, use a 10 speed or 13 speed trans, and set the cruise speed to be at the bottom of the engine's sweet spot at about 58-60 mph. I'd have the governor set no higher than about 67, and run the truck like I didn't know where my next dime to pay for fuel was coming from.

    I wouldn't haul any cheap freight with it, and wouldn't let anyone bully or persuade me into any unrealistic delivery schedules. I would make sure that the company pays a full surcharge updated at least weekly, and make sure that there is an agreed on process for paying for any lumping and detention time. And if they didn't do all these things, I would tell them goodbye.

    Doing those things, you can be around trucking a long time. don't do them, and someone else will be buying your truck from Freightliner next year at this time.

    Hope this helps.
     
  4. MACK E-6

    MACK E-6 Moderator Staff Member

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    Burky's advice is usually irrefutable, as is certainly the case here, save two things.

    He's right about the aero trucks, but some of these are simply hideous, such as the 387 Pete, and those T2000's. I, for one, wouldn't want to own an ugly truck.

    "The engines sweet spot of 58-60 mph"? Wait a minute now. First of all, this depends on the engine. For example, I've found that the Mack Maxicruise engine found in Vision models performs best between 1100 (peak torque) and 1500 (peak horsepower) RPMs. Second, at what speed that is depends entirely on gearing.
     
  5. Burky

    Burky Road Train Member


    I never specified an rpm. As far as I am concerned, you start setting up a driveline at the front of the truck. Choose the correct "sweet spot" running rpm for your truck's engine, then work your way back. Go through the trans, the rears and the tire size and keep making choices until you have the speed you want to run set at the best rpm for that engine to be working. My point about 58-60 with a load on is that you will make good time at that speed and get your best mileage right there, and keep the penalties as low as possible for pushing air out of the way. And you can still move the rpm upwards when empty, since once you shed the weight of the load, you don't see much harm in running a bit faster.

    And since this is primarily along the eastern half of the country, you don't get much advantage in running faster than that. I'm basing my advice on someone buying his own truck and having to pay for the fuel. Regardless of how cool it is for a driver to be able to run 68-70 or so, it's an unchangeable fact of physics that a truck gets better mileage by pushing the least amount of air possible and at lower speeds, where the aerodynamic effect is greatest.
     
  6. Duckie

    Duckie Light Load Member

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    It depends on what you are gonna haul, I haul heavy 90% of the time so I have a powerhouse, what do you want. First truck go with what is effecient, next truck you will know what you want.
     
  7. Burky

    Burky Road Train Member

    I haul 48-50k almost every load that I pull, running as far west as Omaha, east to the water, North into Canada, and south to water. I get by just fine with a 380/410 truck. Having a lot of hp is not always the best strategy. Every horse in that engine demands feeding, and you feed them through your foot. I may not top a hill quite as fast as you will with 550 hp, but I get up there at a reasonable pace. The point of the thread is getting the best mileage to spend the least money on fuel as an owner operator. If saving money isn't important, by all means get a big truck and a big motor and gear it to run 70 loaded. But that's not the best way to make money with the truck. It's not about how much you gross, it's about how much you net.
     
  8. Tip

    Tip Tipster

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    Burky, I have to say I've learned a LOT from your posts, man. I don't really know that much about being an O/O, at least when it comes to the equipment side, but I'm learning more and more....especially from you. Some of what you post wouldn't apply to me, but I still find the info informative.

    I appreciate it.

    Let me close by listing the latest version of my O/O truck, a truck that would be pulling a dry box regionally and coast-to-coast:

    1. Model: Used KW T-2000 or the Pete 387 with the deep sleeper and about a 230" wheelbase and around 350K miles. I'd pay cash for it and wouldn't pay more than around 30-35K. Of course, I'd make sure I'd get all the records and receipts (and would turn up my nose at any rig that had even ONE receipt missing), and make sure its ECM reading is accurate.

    2. Engine: Probably an N-14 with a split rating. 350 on level ground, 425 on hills. I'd want it governed so my top speed would be around 68.

    3. Tranny: 13 speed EF.

    4. Rear-End: A ratio that gives me the 68 speed at around 1500-1600 rpm in high gear on level ground. This ratio depends on tire/wheel size. Being as I'm not sure what the figures would be for those items yet, my ratio at the moment is unkown. I'll have to decide on tires and wheels, and then run them through my equation to find the ratio.

    5. Options: Auxiliary generator for sure. On-board fridge (to help cut down on meal costs).

    Thoughts? Advice?