cold weather mpg

I thinks it's normal.
I'm in a brand new peterbuilt.
Seems like every time I go north into cold weather
I get about a mile per gallon less than I do in the warm weather.

Don't ask me why,I'm just a certified steering wheel holder.

 

Your numbers sound about right

When I was going to edmonton from kelowna with a tridem up to weight, I'd be about 450 there and 400 or so back? That was loaded both ways in warmer weather mind you.

Btw 1550 at 100 i bet your ratio is 4.10ish (if you have 11r22.5 rubber)

 

At -20 tire rolling resistance is increased because tires become less flexible the colder they are. Any ice on the road will also decrease your mileage, due to micro-slippage. That includes ice that is not visible, like the frost from ice fog or airborne ice crystals in northern Alberta, for instance.

Pulling a loaded Super-B (lots of tires) away from Watson Lake on the Alaska Highway after it has been sitting for the night at -40 is like having a third trailer. After about half an hour of driving the tires will warm up (from internal friction) and have less rolling resistance but will remain comparatively slow as long as the temperature is low.

There are winter tires that roll better (and stick better) at low temperatures but the treads are made of compounds that wear like pencil erasers if the temperature goes up or if you are driving south.

Deep blocks (knobbies) on winter tires decrease your mileage because the block flexes (which is what makes the block stick to icy roads). The warmer it is the more the block can flex.

Your mileage can also decrease slightly if your engine is running cold. That is possible if you are empty and you have an insufficient winter front. Keep an eye on your water temperature, especially if it is -30 or -40.

 

In Michigan hauling 157,000 pounds with a n14 500ish power 13 speed truck avg 3.8 mpg for round trips. This was a 8 axle double trailer combo. Truck ran 1700 rpm at 68mph.

 

Trucking Today magazine a few years back did a good article on the science of winter fuel economy.
The difference from summer to winter blended fuel accounted for about a 4% drop in mpg.
Stiffer drive train was another 1 or 2%.
The biggest factor was the air temperature. Cold air is a lot more dense than warm air. It takes a lot more power to push that dense air mass out of the way. They figured it accounted for about 15% of the drop in mpg.
So adding it all together, about a 20% drop.
You had 6.0 in summer less 1.2 (20%) = 4.8 mpg.
So you are pretty close to normal.

 

I lose around 1 mpg in the winter also. I pull heavy too but on flat ground so its easier on fuel. I would try to get to 5 mpg. That should be doable with a n14 if you drive for fuel mileage. That amount of idling won't have a huge effect on your mileage. Never shutting the truck off for days on end will drop it a noticeable amount.

 

That is a good point about the cold air. If you are sailing in the Southern Ocean the cold, dense air from Antarctica makes you go faster!

 

Cold air is good for power.
Hot air is good for mpg.