Some simple math regarding fuel economy

the actual sweet spot on many trucks is indeed 72-75 mph-no ifs,ands,or buts.therefore to drive slower does decrease the mpg-

 

Your math is flawed.

Let's call the 75 mph truck 'C'
75 mph x 10 hours = 750 miles divided by 5 = 150 gallons X $4 = $600
600 - 344 = $256 extra per day
Not sure how you came up with the 193,440 extra in fuel ... 193,440 / 256 = 755 days ....

Instead, I prefer to look at fuel cost as a per mile cost.
$4/g / 7.2 = 0.5555 per mile
$4/g / 6.8 = 0.5882 per mile
$4/g / 5.0 = 0.8000 per mile

Now, if one can keep the cost of fuel (PER MILE) at their determined PERCENTAGE of gross revenue(I try for 25-33%), you will still be good to go. These adjustments can be made through smart fuel purchasing and driving efficiently, as well as MPG upgrades.

Now we have the difference between good paying loads and low paying loads. I have found that when a load needs delivered by a certain time in order for shipper to keep their customer happy, they are more than willing (most times) to pay a bit more if they know you will get the job done. This more than compensates for the added cost in fuel. Also keep in mind that the aero truck that gets 7.2 at 62 mph is not likely to have a swing down to 5.0 mpg if it began moving at 75 mph. If that were true EVERY truck on the road would be going slow. On the flip side, that big shiny 379 getting 5.0 at 75mph, would probably do well to get 6-6.5 at best if it were to slow to 62 mph.

There is also the issue of how many miles can you put on your logbook without the DOT getting on you for it. It is better to use estimates of how many miles you will run in a given time. I like to use a few different scenarios of 80k, 100k, 120k miles per year.

Ever see the bull wagons and reefers just flying in the middle of the night?

MPG is a big factor, but it isn't everything.

 

The trucking companies are the ones who make the decisions on how fast the trucks go. They don't care about how much the drivers make they care about fixed expenses (the loan payment on the truck & trailer, insurance, etc..) and the non-fixed expenses/operating cost (fuel, oil, etc..). So if they can save $100 per week on fuel cost that is $5,200 per year times 5,000 trucks = $26,000,000 per year.

Mega-carriers have a little more leeway with making or changing appoints then a small company like mine with only 56 trucks. I could pay my truck and trailer notes and all my expenses with 1000 miles a week. I'm sure a mega-carrier even has a lower overhead and operating expense.

 

This is the mistake. You may drive an additional 4030 miles but it will not cost you an extra 16,120.
With your math, 4030 miles at 5 mpg = 806 gallons X 4 = $3224. That is not extra fuel cost, that is just the total fuel cost of those extra 4030 miles.

 

There are so many variables which is why this topic goes on forever. What if I'm headed down the road and short on time. If I do 65-70 I can make it to the customer that day and dump off. Which might mean that I can reload that day and get back up the road to dump off in the morning but if I do 55 I'll be sleeping at the customer that night and won't dump off til morning and therefore I'll have to spend most of that day reloading and coming back up the road. If that goes on and on for a week, month, year. I'm losing a lotta money sitting around so I can get another .5 mpg. Just my .02 without getting a lot of arithmetic involved and this is really just an example for me. I fully understand that non bulk haulers deliver and load in a completely different manner than I do... If u no what I'm saying

 

Your arguing just to argue here. The laws of phuics do not change from one truck to the next. Load and weight do.
Engine sizes gear ratios, alot plays in/

Less drag means better mileage.

My running weight in my new Coronado is 79800 lbs average. DD13 425 hp, 10 speed pulling double pnuematics.
I shift about 16oo rpms on the flats, but I also run it up to 2000 pulling the hills ( the Grapevine / Tehachapi ). Currently running Victorville to Modesto (395/58/99 north, 99/138/18 south) ;loaded both ways.

At 55-58 I average 7.85 mpg, At 60-62 my average drops to 5.90. Loaded both way less than 20 empty miles in a 545 mile day.

My Cascadia with a dd15 set at 600 52-55 averaged 4.85, 60 -65 4.15/ still a difference but with the extra hp, it was not as nig of difference but still changed none the less. The 600 sucked all the time on mileage.

 

Excellent points. I think this topic is not a ( one size fits all).

 

Not speaking at you Pwdr Joints, just generally... and thx!


I know I've been out of designing/ and spec'ing trucks for too many years to follow computer enhancements... but the internal workings are still the same. This is a perfect example of knowing your rig... you have a sweet spot for torque (where you find best mpg/hold speed uphill) and another for horse power (get it moving/acceleration). All of which is determined by your transmission, and rear end gearing.

For example: an E7 Mack engine is still an E7 no matter if its rated @ 350hp or 425hp. You still have the same sweet spot. If the driver abuses the extra ponies you loose mpg, but if he knows the engine and given the proper gears he can out perform the 350hp in mpg by %2-3.5 optimally.

I'll say it again, speed kills MPG! But be dang the common thinking that restricting drivers to 62 mph is the best answer. Teach them the truck and stop mass manufacturing morons that need to be babysat by computer. JMO money savings would be better spent offering a fuel mpg bonus rather than an everyone suffers solution.

BTW did you know the most fuel efficient truck when the T series Kenworth was released... was still the 1988 Kwhop cab over. The cab fairings to trailer were designed too long.

 

i'd like to know who here makes the same amount of money working less then those working harder.

and i'm talking the same category people. cuz brutha, i made less with the last company then i did the first company.

less miles. less pay.

an o/o might make more depending on his freight. but all others. that rely on teh miles. i don't think so.

that would be YOUR 2 year e xperience misnomer.