Over tire inflation

I had my oil changed and tire check done yesterday. When I started on the highway, my car seemed to be hard to control. It was raining. I noticed that my tires were all inflated over 40, one at 45. I called today to complain and he said that they set all tires at 40. I told him my car seemed skittish and hard to control and he said, “I find that hard to believe” I stopped and released some air and things were better. Is that a routine thing to set at 40. My car door says 32.

Don’t let those people touch your car again!




It’s such a shame that @Terry_Mateya had to wait so long for a reply and then such a long and indecisive answer. I’m sure you’ll do better next time @Tester.

Yeah, I don’t get how a shop could miss that. Just fill 'em to the pressure on the door unless the owner tells you something different. Not that hard.

You should have lowered the pressure to 37 PSI then check them in the morning to see if the pressure is correct, the tire pressure increases by 4 to 5 PSI as the tires heat up while driving.

Also one must consider the shop temperature compared to the outside morning temperature when filling tires. If the shop is 70 F and the outside morning temperature is 25 F the technician must add 4.5 PSI to the value shown on the tire inflation label or the tires will be under inflated once cooled.

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What I do is, I raise the vehicle on the lift to do the oil/filter change.

By the time I’m done with the oil/filter change, the tires have cooled off.

Then I do a tire rotation as a courtesy service.

Once the rotation is performed, I check the door placard for the proper pressure for the front/rear tires.


I can understand why the ride would feel a lot different at 40-45 psi vs 30-35 psi. I can notice a difference in the ride quality and handling on my Corolla , 35 vs 32. 32 is a lot better on both counts than 35. I can’t even imagine what 45 would feel like, but it wouldn’t be good. On my truck, tire pressure differences affect ride quality too, but it isn’t nearly as evident.

OP, next time suggest that before leaving the shop after that service, bring along your own tire pressure gauge & check the tire pressures yourself; also check the oil level on the dipstick, and that no oil is leaking under the car.