[JMBisMe]

1. So I've seen some weird GOM behavior lately on my 2020 Bolt now that the weather is cooler (it's my first winter with it). Here's what I've seen: driving along when it's cool or rainy with the HVAC system completely off. Then I press the buttons to turn the upper vent and windshield/defog on together with just the fan, no heat. The GOM will go down for a second, then jump back UP several miles higher than it was before I turned the HVAC on. I can then turn both vents and the HVAC completely off again and the GOM stays at the higher value.

Cool way to get some free miles I guess? I know that I'm not actually gaining any range, I'm just puzzled why the GOM seems to think I am.

Had noticed previously that when you press just the windshield defog button it seems to run the AC compressor and/or heat to dry out the air and GOM goes down. But when you press defog in combination with another vent it just uses cabin air without the AC or heat and the GOM doesn't go down (now mine goes UP). My auto de-fog is off FYI.

2. Also, this week I had my new 205/60R16 X-ICE Snow tires on 16" regular Cruze rims (not Eco) installed. I reset my trip meter when they were installed. I'm getting 4.7mi/kWh in ~40F temps through about 140mi of around town and some highway driving...significantly better than I was getting with the stock tires at similar temps recently. I had kept the stock tires right at 39-41psi cold. I was expecting my efficiency to go down, not up. Are these new snow tires magical? This is non-scientific anecdotal observation, but I'm happy.

For reference, only have ~6600mi on the car

 

[jefro]

My HVAC system is totally unreliable at doing what the controls are set to.

Are these tires exactly the same rotations per mile?

Pressure in the tires can sometimes improve mpg. Normally on an EV the rolling resistance is the issue. Lower is more mpg.

 

[NoMoPetrol]

That's why it's called a GOM - a Guess-O-Meter.

 

[gonnabolt]

If you reset the trip meter, and look at the efficiency on the same screen, it heavily weighs the results to the presumed factory number (4.9?), you have to drive many many miles before it balances your usage accurately in the display.

 

[JMBisMe]

If you reset the trip meter, and look at the efficiency on the same screen, it heavily weighs the results to the presumed factory number (4.9?), you have to drive many many miles before it balances your usage accurately in the display.

Yes it resets to 3.9mi/kWh by default but pretty quickly starts recalculating as you drive. I was surprised that it started going up from 3.9 while I was driving in the highway

 

[JMBisMe]

Are these tires exactly the same rotations per mile?

Original 215/50R17 Michelin Energy Saver A/S = 815 rev/mi

205/60/R16 Michelin X-Ice Snow = 810 rev/mi

That’s only a .6% difference though. And the car would think it had travelled .6% shorter distance with the snows than factory, leading to a mi/kWh reading that was lower than actual, right?

 

[chrisj428]

Never mind...LOL! Running on no sleep.

 

[BobBolt]

1. So I've seen some weird GOM behavior lately on my 2020 Bolt now that the weather is cooler (it's my first winter with it). Here's what I've seen: driving along when it's cool or rainy with the HVAC system completely off. Then I press the buttons to turn the upper vent and windshield/defog on together with just the fan, no heat. The GOM will go down for a second, then jump back UP several miles higher than it was before I turned the HVAC on. I can then turn both vents and the HVAC completely off again and the GOM stays at the higher value.

Cool way to get some free miles I guess? I know that I'm not actually gaining any range, I'm just puzzled why the GOM seems to think I am.

Had noticed previously that when you press just the windshield defog button it seems to run the AC compressor and/or heat to dry out the air and GOM goes down. But when you press defog in combination with another vent it just uses cabin air without the AC or heat and the GOM doesn't go down (now mine goes UP). My auto de-fog is off FYI.

2. Also, this week I had my new 205/60R16 X-ICE Snow tires on 16" regular Cruze rims (not Eco) installed. I reset my trip meter when they were installed. I'm getting 4.7mi/kWh in ~40F temps through about 140mi of around town and some highway driving...significantly better than I was getting with the stock tires at similar temps recently. I had kept the stock tires right at 39-41psi cold. I was expecting my efficiency to go down, not up. Are these new snow tires magical? This is non-scientific anecdotal observation, but I'm happy.

For reference, only have ~6600mi on the car

I've owned a few sets of X Ice and now two sets of X Snow and while I can't say I have seen the efficiency go up...I can certainly say it does not go down. This idea that winter tires are range killers is likely true for the cheap stuff. Those also tend to have lots of vibration and noise as well.

 

[Voldar]

1. So I've seen some weird GOM behavior lately on my 2020 Bolt now that the weather is cooler (it's my first winter with it).…

40F - That’s no cold, it’s only just right. As for the GOM issue, you changed the 17" with the 16", and no, the linear math doesn’t apply in this case. The range estimation is based on more than the dimension of the tire.
Just a question, is the GOM behaving as you say every time you go out to drive or from time to time or it was once and never again ?

 

[jefro]

I'd have to assume the rolling resistance has been reduced.

 

[JMBisMe]

Just a question, is the GOM behaving as you say every time you go out to drive or from time to time or it was once and never again ?

I've seen the GOM go up multiple times in this scenario. Just started noticing it now that the weather is colder.