I bought my Bolt back in mid-December 2017. I had never checked the tire pressure, other than glancing at it on the car's display, which reads it from the built-in tire gauges in each wheel. I was giving my baby Bolt a bath a couple of days ago, and I figured it would be a good idea to check the tire pressure with a decent gauge. All four tires were overinflated: about 42 psi, versus the door sticker's recommended pressure of 38 psi. So I dropped the pressure to 38 psi. Don't trust your car's TPMS (tire pressure monitoring system). I'm hoping the reduced pressure will help the braking and cornering, but it will also likely reduce my mileage slightly.