Fuel Economy fuel economy - classic vs. aerodynamic trucks

Van Wyk came to the same conclusion with the super singles. They didn't last as long as they were supposed to, didn't get the advertised MPG increase, some late loads & costly roadside service when one would blow out 200 miles from the nearest shop that had a replacement (and an alloy rim) in stock. Uneven tread wear, drivers complaining they had no traction in snow, etc.

And that was with the auto-inflation systems on the trailers & cat eye monitors on the drives.

They ran that equipment out til trade but went back to duals on new orders.

They made a similar decision to dump either the tails or the skirts recently but I can't remember which one. I hope it was the tails because they're a pain in the ass in the winter when snow gets on them. And they look stupid too.

The only thing about the skirts I don't like is on some of them, to make room for the skirts they mounted the reefer tanks too far from the edge and it can be a pain in the ass to get the fuel nozzle in them.

So... what kind of tires and model were they using? Not all wide singles will deliver the performance increase.
 
So... what kind of tires and model were they using? Not all wide singles will deliver the performance increase.
I'd have to go digging through old posts to find it. I've posted it before but forgot.
 
So... what kind of tires and model were they using? Not all wide singles will deliver the performance increase.

Michelin probably has the best one (lowest rolling resistance), but even then, you can get duels so close to the same rolling resistance that the mpg increase would not even begin to be noticeable.
 
Very true. That is why I never advocate someone changing over to wide based, unless they are looking for a little weight savings. There are some really good low RR standard tires that will give as much economy as wide based. Now, I run wide based, but I ordered it that way from the factory, so the cost was nominal. I would probably never switch a truck from duals to wide based.

As for lasting as long as standard duals, it all depends on the setup, and many fleets and owner have no real clue what they are doing. Like axle length. Axles come in 3 lengths, standard, intermediate, and wide. I spec'd intermediate axles. That allows a wider stance with wide based rubber, but I can still go back to to duals if I needed to, though instead of a 96" width with duals, I would have a 102" width with duals. And I used Zero offset wide based wheels. Many go to with 2" offset wheels that put excessive strain on bearings and increase axle flex. Tire wear tends to go up.

With my setup, I got 447,000 miles out of my wide based, they still had 8-9/32 tread left, no uneven wear, and I got $180 for each wide based tire when I changed them out last month. It is all in the setup. Truck has averaged 7.93 mpg for it's entire life. I only use Michelin wide based and I get a good pricing value from my tire dealer. I just did all the wide based and the steer tires, got $1020 for all the old tires, and got the new tires for a total of $5200, minus the $1020, and I got all the tires changed out on the tractor for about $4180. I got 447K out of the old drives and 227K out of the steers. Very cost effective for me.
 
I drive for a big fleet in the Canadian Maritime provinces (NB, NS, and PEI). I have noticed that the MPG I get varies as follows: 5.8 to 6.2 when I'm pulling 68 000 lbs (tridem dry van limit) and up to 7.8 when I'm hauling 10 000 lbs of LTL. And it varies from 6.8 to 8.2 when I'm empty. I drive a 2012 Volvo VNL 670 with a 15 litre Cummins that's turned down to 435. It's got a 10 speed. Rears... I dunno, it turns about 1450 at 62 mph, so whatever that works out to. Anyway, based on my limited knowledge here's what I think is going on: The two biggest factors that affect your fuel mileage are, the trailer by itself and then the weight in the trailer. We have some trailers that you don't even know are there and we have some others that pull harder empty than others that are at their limit. The next factor is where you're running. It's tough country here on the East Coast (hilly, windy, and in the winter... well c'mon up and try it out). The next biggest factor is the driver. I'm a little better than average, if you look at the company fuel mileage stats (they publish them for all to see). The last factor is the truck, but it's an important factor because if it's not set up to haul the weight you're hauling in the terrain you're running in, it won't matter how good of a driver you are or how easily the air passes over your truck, you're gonna burn fuel. I believe aerodynamics are important to some extent, but it really depends on the application. I do not believe that there is a 1 mpg difference truck for truck. There is a tenth to three tenths, that is why fleets buy the "ugly ducks", because it's an aggregate savings. If 0.1 to 0.3 mpg over 100 000 miles is the difference of you staying in business or not, then maybe you have bigger problems. There's tons of Classics, 389s and W 900s running up here... there's not a lot pulling vans, but there are tons of them pulling bulk stuff and decks, because it doesn't make a bit of difference with the weight they're hauling.
 
Our 610, 611, and some 612 series trailers have skirts and tails but the newest 612, 750, and 755 trailers ditched the tails. Most of the time they weren't even deploying.
 
I always thought aerodynamics was a major factor ... BUT . When I drove for Cypress the old 389 Peterbilt with a cat , 1999 I think , and the 99 Freightliner SLD Both got better fuel mileage than the new Peterbilt I drove .
Sure their are multiple factors that caused this but I know every international I've driven , both auto and stick get the worst fuel mileage of anything I have ever driven .
 
I always thought aerodynamics was a major factor ... BUT . When I drove for Cypress the old 389 Peterbilt with a cat , 1999 I think , and the 99 Freightliner SLD Both got better fuel mileage than the new Peterbilt I drove .
Sure their are multiple factors that caused this but I know every international I've driven , both auto and stick get the worst fuel mileage of anything I have ever driven .

Decent MPG out of emissions engines is a challenge, over well maintained older engines.

It's just that the hippies thought we were putting too much bad stuff in the air. So now we just use more fuel but supposedly burn it cleaner so it will take longer to Earth to become the same tropical garden.

I say this because I don't think we hit 20 degrees today.
 
LOL . I'm not against clean technology but I'm also a realist , so I understand that even though someday we may not get around with fossil fuels , today isn't that day and it will take time to get to that day . Damned Progressives think they can just say , WE WANT IT LIKE THIS , and it just happens. LOL
 
LOL . I'm not against clean technology but I'm also a realist , so I understand that even though someday we may not get around with fossil fuels , today isn't that day and it will take time to get to that day . Damned Progressives think they can just say , WE WANT IT LIKE THIS , and it just happens. LOL
Global warming /climate change has been debunked as a hoax many times over. But it's still not a good idea to pump gazillions of tons of toxic stuff into the atmosphere if we can avoid it.
 
I'm working on a truck that runs on unicorn blood.

It's estimated to get 4,500 miles per gallon and cost $1,789,456 MSRP. But don't worry, there will be rebates.

On a more serious note, I follow this stuff and am still on the fence with respect to which purchase direction to go, similar to an O/O deciding whether to "upgrade" or not.

There's a strong argument in favor of less spent on older equipment and potentially more in fuel/maintenance but an equally strong one in favor of equipment for comfort/convenience/economy.

Staying local though I think favors the old stuff. You don't get great mileage anyway doing relatively short hops, loaded, with an inefficient rail container behind you. And those emissions systems run best when you have the highway stints. They wreak havoc on the constant start up and shut downs of local work.

But man I'd love to have some of those modern creature comforts even for the medium length hauls.
 
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Its mostly all that junk hanging off the classic large cars that kills the aerodynamic efficiency. Loose all that chromed junk (which, of course, gives them the "look") and they get a lot more efficient at moving air out of the way.
"Chrome junk"

Hand over your CDL, driver.
 
Has anyone got numbers for a yearly average for DEF usage?
Any increase in MPG would get offset by DEF costs, right?

I don't get too fussed over MPG, I think what's more accurate is how much it costs to move it one mile. Fuel, insurance, plates, maintenance, etc divided by miles that month. As an opinion
 
Has anyone got numbers for a yearly average for DEF usage?
Any increase in MPG would get offset by DEF costs, right?

I don't get too fussed over MPG, I think what's more accurate is how much it costs to move it one mile. Fuel, insurance, plates, maintenance, etc divided by miles that month. As an opinion
Fuel and what you pay yourself (and employees) are your two largest controllable expenses.

Cut back on what your right foot is doing, and the lump under your left cheek gets more uncomfortable.
 
Has anyone got numbers for a yearly average for DEF usage?

Can't remember the costs for that crap, but it's pretty low per mile. Your looking at 100+miles per gallon, can't remember the exacts I was getting. It adds up though. Everything adds up.

And, the harder you run the truck, the more you spend on DEF. Running the truck efficiently has a big effect on DEF usage. Starting running the truck hard, your fuel mileage drops, and your DEF mileage drops right along with it.
 
The price of DEF at least has remained the same for the most part for couple years at least . Think it's remained around 2.75 for 3 years , no ?
Anyone from my habit it seems to run about 10 dollars a day and I top it up every second to third fill up .
 

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