companies with fast trucks

Your right about safety, but fuel mileage plays a big part as well, and yes the way your average fleet trucks are spec'd they will get way better fuel mileage at 55 to 60 then 70 to 75. Even if you have to drop gears more often, which by the way there are only a handfull of hills in Iowa that require you to drop more then one gear and that probably acounts for less then 1% of total drive time in Iowa. You use way less energy fighting head winds at 63 versus 73 since wind resistance is exponential as well as rolling resistance. Even trucks spec'd to run faster will do better if they drop their speed without lugging the engine. Yes there is a limit and you can't lug the engine beyond what the engine manufacture says (not what the cb says), but otherwise going slower will save fuel. I do not care what anybody says on this website or on the CB nor do I care if they own a truck because they apparently have never done any long term experiments if they claim they get better fuel mileage running faster. The reason you see produce, seafood, cattle, air cargo, etc, etc trucks running faster is becuase they have to in order to get the products on the shelf faster, cows out of the trucks, and air cargo on the planes. Other trucks run faster either because they can afford it and or because they are maximizing their productivity, and or never tried to run slower for a few months to compare their fuel mileage.
My best friends Parents owned a medium size company out of Memphis, operating about 30 tractor trailers and 80 straight trucks. My best friend was in charge of specing and buying the trucks. Despite their trucks running 78mph and spec'd to run that speed, both him and his father would tell you that the trucks would get way better fuel mileage going 10mph slower. I owned a truck for 5 years and I caclulated my fuel mileage all the time and filed my own fuel taxes. I had a couple dedicated runs during that time and everytime I had to run faster my fuel mileage dropped off. You can't just look at the trucks dash to check your fuel mileage every now and then. You have to actually divide your miles by how much fuel you put in and do that several times and factor in what terrian your driving on, your average weight, and what fuel your useing and do this over several months at lower speeds and then several months at higher speeds. It's just simple physics. The faster you go, the more energy is required to overcome the wind resistance and rolling resistance which means more fuel (your source of energy). It's that simple.

On top of that, going slower reduces tire wear, brake wear, and a whole other host of componants.

Keep in mind, I'm not trying to tell people to go slower, heck I could careless what speed you drive. Sometimes I drive fast but please keep it real when your telling others what happens to the fuel mileage when you run faster.

 

Thanks Lego, I'm glad you explained it to them, I just didn't have the energy too. Some people can't help but spew that CB radio BS on here

 

I'm gov at 62...I got 8.157 today after I filled up...I run saginaw mi to atlanta and back

 

Makes sense to me .

 

I'm glad he explained it as well, but chances are they won't believe it.

 

When the company services the power unit it will tell them the date and time of when it was turned up, now the savvy drivers is free to explore other endeavors....

 

While I understand the physics and agree with what your saying regarding wind resistance.

I'm refering to changing(spec) how the powerplant works, or limiting the top end. Will also effect, fuel economy.

For example, a manufacturer say Detroit, will design the powerplant with an economy curve. Say, increased milage up to 40MPH a slight drop then another increase at say 65MPH then dropping off again to increasing less fuel economy with greater speed.

This curve IS developed with optimal power plant operation(ie wide open). NOT some yahoo, messin' with the limit and chokin' it down. Again, it goes down the chain the turbo will not work properly, the emissions systems will not work properly(Peterbilt w/Cat) "Reported fuel consumption for heavy-duty engines has declined to 5.72 mpg in 2006, down from 5.91 mpg in 2005 and 6.04 mpg in 2004."

While there are certainly many variables involved, I stand by my statement that governed trucks will NOT increase fuel economy. Driving slower in an ungoverned truck will!

 

From what I can surmise, it seems like a combination of things that comprise the companies' decisions to govern trucks to such ridiculously slow speeds: 1. Insurance 2. To influence drivers to become slaves to a lease-purchase option. The latter is primarily because one company representative said, "...but, if you decide to lease one of our trucks, we'll pull it into the shop and open it up for ya~!"

 

I took a trip to FL in my ungoverned pickup not long ago. Ran with traffic on the way down (70-75mph) then drove home, same route, with cruise set at 65 or just under and got 4 more mpg. Being a motorcycle rider with my face in the wind, I can say there is a huge difference in wind between 65 and 75, so I'd say speed does have alot to do with mpg. just my 2 cents

 

...and drivers'wages too