62 MPH rule? What is the reasoning behind it?

drag coefficient is a major player in mpg. Wind resistance increases 36% when speed increases from 60 mph to 70 mph. That additional drag is all extra fuel out the pipe. Reduce the drag, increase the mpg,

 

Had a 2008 midroof Columbia with a 430 detroit and a 9 speed top 2. Truck ran 69 mph and got 7.5 mpg. Company got influenced by the beancounters and they cut the truck back to 64. Fuel mileage dropped to 5.5. Driving on 2 lane roads became more dangerous (as it is more difficult to pass farm equipment) and you have less momentum for the uphill grades, which means the engine has to work more to pull the same hills. More bigtruck dragracing, more frustration, more fatigue on the driver from dragracing.

It allows stupid people to drive trucks. Beancounters figure that stupid drivers should be able to maintain better control with slower trucks. Point is however, stupid people should not be driving period. Put a dummy in a truck and pay him less. Now all the companies have to do is figure out how to get the driver to pay for the money in fuel theyre losing.

 

I always thought it was so I could practice my lane changeing skills. A lot.

 

Simple physics, slower speed means less fuel burned....bean counters

insurance....slower speed, less deaths or so they think!!!

Canada, Speed limiter law is 62 for US trucks that go into those areas of Canada that require it.

Tires they are now putting on most company fleet trucks are rated for 70 mph max.

 

Sorry , wrong . The speed limiter must be set at 105 km/h
105 km = 65.2439 mi.
OR 65 mi. and 429.3 yd
You people listen to the C.B. too much .

 

Very true . The rpm range at a given speed is a factor .

http://www.highwaystar.ca/careersfeature.cfm?ID=419

 

These companies are too stupid to figure that out though. Common sense is not so common anymore.

 

Your post does not completely disagree with mine! I said there are certain situations where turning faster saves fuel...like winding it up to a faster speed right before a grade, making the grade easier to pull...you get up it faster, it fatigues you less, you downshift less, and you use less throttle. Thats the biggy.

I also have a 9 speed and i feel like it is not enough gears and that it's killing my economy. In certain speed limits in cities i have to have the engine revved up to 1500 to 1600....if i upshift a gear, the engine is lugging, so i have to have it overrevved like that, *wasting fuel*. I hate that transmission with a passion.

Theres also a speed under which you're using more fuel than if youre going faster. It depends on the vehicle, and I know for cars its around 55mph. So thats not really an issue. I remember one time my dad was doing 40 on an interstate highway to save gas, I tried and tried to explain thsi concept to him, but he didnt get it. And did i mention it was ILLEGAL? god.

 

Optimal speed for the Gear you are in. I am governed at 72, I know how to coast down hill as much as poss. and I know how to keep the RPMs down and .... UP.

 

As mentioned here, keeping the throttle right up against the governor the truck will burn more fuel, but if you keep it down a couple mph below that, it will get better. Also it does depend on how a driver takes off and shifts gears, if you take off easy and shift without your foot in it, it helps a lot. Take off like Jimmy Johnson at the race and keep your foot down on the throttle between gears and suck lots of fuel. I have also done something that gained mileage that your not SUPPOSED TO DO, which is going down hill free wheeling,, or taking the truck out of gear. It did help on mileage some. But i do hate having to drive a truck set at 65, when states like utah, wyoming, nebraska, nevada are all 70 to 75 for trucks and i get passed by every dang truck thats not set at 65, or i get passed by the little green man on the moped with his teeth full of bugs lol. But you do what the company you work for says to do, thats the rules.