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I live in place that routinely goes below freezing in winter. I’ve never noticed gas mileage change because of temperature. I would definitely notice a differen

I live in place that routinely goes below freezing in winter. I’ve never noticed gas mileage change because of temperature. I would definitely notice a difference of 8 MPG. Where do you get that info? Is it personal experience? If so, where do you live?

simfree 4y ago
Here in the Pacific Northwest, driving both last winter in BC and currently in the mix of snow, freezing rain and slush. I'm using the same three peaks rated all season tires as I was using in the summer, and driving the same routes as well.
gambiting 4y ago
I easily notice the difference in my car, it goes from about 8L/100km in summer to 10L/100km in winter. That's on the same tyres in both seasons.
- bch 4y ago
  Driving through snow?
  - gambiting 4y ago
    No, just driving on the motorway, at a solid 140km/h. Did the exact same drive in winter and in the summer just this year and that was the difference in consumption(I want to add that I can see the difference in daily use too, but I just happened to do the exact same 700km drive where the only different factor was the season of the year, so it gave me a very good reference point for specific numbers).
    - adrianN 4y ago
      It's even worse for city drivers doing short trips. The engine doesn't have time to heat up properly before you reached your goal. Fuel efficiency is abysmal and the exhaust treatment systems barely work.
kevin_thibedeau 4y ago
Cold air is denser. Pushing it out of the way saps more energy and drops the effective work done. You're oblivious to it because a motor vehicle has so much available power on tap. It is very noticeable on a bicycle at high speeds. Conversely. Sailboats get more efficient in cold temperatures because more energy is imparted on the sail.
- Gordonjcp 4y ago
  > Cold air is denser. Pushing it out of the way saps more energy and drops the effective work done. That makes absolutely no difference at all.
  - sokoloff 4y ago
    > That makes absolutely no difference at all. That would be very surprising if it were true, given the very large effect density altitude has on airplane performance (engine and wing).
    - maxerickson 4y ago
      It's gonna make some difference, but air resistance goes with square of speed and the change in density due to temperature isn't that large.
      - sokoloff 4y ago
        It’s about -3% change in drag force per +10°C change in temp.
        maxerickson 4y ago
        Which is like the same as 60 mph vs 59 mph.
        sokoloff 4y ago
        In drag force, yes, but in this case, you are taking the 3% penalty and aren't getting the partially offsetting 1.7% increase in distance per unit time that 60 gives you over 59. Note that it's 3% per 10°C delta so, for a 40°C swing (say 30°C/86°F summer to -10°C/14°F winter), that's a 12% difference in aero drag force.

simfree 4y ago

Here in the Pacific Northwest, driving both last winter in BC and currently in the mix of snow, freezing rain and slush. I'm using the same three peaks rated all season tires as I was using in the summer, and driving the same routes as well.

gambiting 4y ago

I easily notice the difference in my car, it goes from about 8L/100km in summer to 10L/100km in winter. That's on the same tyres in both seasons.

bch 4y ago
Driving through snow?
- gambiting 4y ago
  No, just driving on the motorway, at a solid 140km/h. Did the exact same drive in winter and in the summer just this year and that was the difference in consumption(I want to add that I can see the difference in daily use too, but I just happened to do the exact same 700km drive where the only different factor was the season of the year, so it gave me a very good reference point for specific numbers).
  - adrianN 4y ago
    It's even worse for city drivers doing short trips. The engine doesn't have time to heat up properly before you reached your goal. Fuel efficiency is abysmal and the exhaust treatment systems barely work.

kevin_thibedeau 4y ago

Cold air is denser. Pushing it out of the way saps more energy and drops the effective work done. You're oblivious to it because a motor vehicle has so much available power on tap. It is very noticeable on a bicycle at high speeds. Conversely. Sailboats get more efficient in cold temperatures because more energy is imparted on the sail.

Gordonjcp 4y ago
> Cold air is denser. Pushing it out of the way saps more energy and drops the effective work done. That makes absolutely no difference at all.
- sokoloff 4y ago
  > That makes absolutely no difference at all. That would be very surprising if it were true, given the very large effect density altitude has on airplane performance (engine and wing).
  - maxerickson 4y ago
    It's gonna make some difference, but air resistance goes with square of speed and the change in density due to temperature isn't that large.
    - sokoloff 4y ago
      It’s about -3% change in drag force per +10°C change in temp.
      - maxerickson 4y ago
        Which is like the same as 60 mph vs 59 mph.
        sokoloff 4y ago
        In drag force, yes, but in this case, you are taking the 3% penalty and aren't getting the partially offsetting 1.7% increase in distance per unit time that 60 gives you over 59. Note that it's 3% per 10°C delta so, for a 40°C swing (say 30°C/86°F summer to -10°C/14°F winter), that's a 12% difference in aero drag force.