gas mileage woes

[Tod up north]

Hello,
I got my 2015 hatchback Sonic last spring (manual transmission.) All last summer the gas mileage I was getting was incredible - hitting 60mpg on highway trips.

Last winter I put some really good, aggressive winter tires on and have kept them on in the summer for getting around better on gravel roads - that's the only difference to the car.

This summer I'm lucky to hit 45mpg. I don't think the tires should make that much difference and neither does the dealer, but they can't find anything obviously wrong with the car.

Yesterday I happened to be putting my travel mug in the console between the seats and I hit the traction control button. I wondered if that would make much of a difference with gas mileage so I held it in a few seconds to completely turn it off and my gas mileage shot back up to what I was getting last summer.

I don't know that much about how traction control works, but my understanding is that unless one of the tires is slipping it shouldn't be coming into play at all? Or will having it turned on adversely affect gas mileage?

Thanks!
Tod

 

[JesusTheAgnostic]

Aggressive tires and heavier wheels will affect mileage more than you think. Went from around 42 to 30 from changing only the tires and wheels. Went with the super grippy extreme simmer tires rated for faster than I'll even go. Also the haters will tell you it doesn't make a difference but I found it gave me about 1 mpg

 

[6speedti]

60 mpg? Yea right. Downhill, tailwind in neutral maybe.
I have a 2015 hatch with 6 speed. If your using the onboard computer then try again. Straight open highway at 60 mph no AC my computer shows 45 mpg. At 70 with AC my computer shows 38 to 40 depending on OAT and humidity levels. 87 or 93 octane has no affect. The engines sensors compensate.

 

[mysterslyckster]

45mpg is good for this car. I've got a 1.4L automatic and steady driving with the cruise set on the highway I see anywhere between 35-50 (according to my ScanGauge II) depending on hills, wind, and other conditions. Using good all season tires too (not the stock Hankookoo's...). EPA estimated highway mpg for my particular car (2013 RS Auto 1.4L) is listed as 33, but I regularly and consistently see 40 on my ScanGauge if I just set the cruise around 65. Heck, my average mpg shown on my dash is currently sitting at 32.9 and hasn't been reset in over a year.

 

[eggsalad]

60 mpg? Yea right.

I bet he's Canadian and using Imperial gallons. An Imperial gallon is 1.2 US gallons, so 60 miles per Imperial gallon is entirely possible.