Why does dealer set tire pressure high?

Our local Toyota dealer often runs specials on oil changes, with the next one free, so for the past three years that’s where I’ve been going. (Changing the filter on the newer – 2011 Venza, anyway – cars is way too hard. Not a simple canister like before.)

The dealer changes the oil, looks for other things to sell me (no problem, that’s why the oil changes are cheap), and we’re both happy campers.

Included with the oil change is to set the tire pressure. I wish it wasn’t, and some times I remember to say not to do it, because my tires never lose more than a pound or two through the seasons. When I need to, I add air in my garage.

The service ticket on yesterday’s oil change showed the tire pressure had been checked and set to 38 psi all around.

This morning, while the tires were still cold, I checked them. 36, 36.5, 36.5 and 37. Looks like the tires really were set to 38.

But the sticker on the door jamb says the tires should be set to 32 psi all around.

Yes, I could get back to the Service Department manager, but what would he tell me that I’d agree with? Or even believe? It’s easier for me to just release some air from the tires.

But I’m curious. How can something as simple as setting the right tire pressure be a challenge for a dealership’s service department?

What am I missing?


Some shops use a tire inflator/gauge.

If the Toyota dealer uses one of these, ask when the last time the gauge was calibrated.

They get banged around when they’re hanging at the end of an air hose reel.


A guess here:
the temperature was higher (not like your morning temp) when the service department worked on your car, and so they estimated 38 psi (6 psi above 32) as the amount to compensate for the temp difference. As it turns out, the estimate was high by about 4-5 psi, which might be an undetectable difference in how your car feels, yet might improve your mpg a bit (while allowing you an extended period of time until the tires dip below 32 and you need to add air)

Tester, yes it could be their gauge, though you’d expect a dealership to keep its test equipment calibrated.

But it doesn’t answer why the technician chose to fill – according to the work order – the tires with 38 psi instead of the required 32.

Then I would go back to the dealer, and ask the technician who worked on your car, “If the oil capacity is 5 quarts, do you add 6?”

Makes no sense!


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I see where you’re going, and maybe it’s the only logical explanation.

It would make more sense if it was two or three psi they were compensating, and writing 35 psi on the work order. But here in San Antonio lately, doesn’t seem much compensation is necessary. The daytime highs are about 90 degrees, the night time lows about 77. Not enough of a difference to need to raise the pressure by 6 psi, right?

Last time I checked, there were four Toyota dealerships in our city. From my address on the work order, they could see I lived nearby, about three miles away. Touching the tires, they could feel they weren’t hot. Not much compensation would be called for.

You’d also think that before adding air, they’d see what the pressure already was, and go from there.

But your idea is the only one that makes any sense right now. Thanks.

I noticed my tires were inflated above the pressure specified by Toyota on the door pillar. My Sienna had just been serviced by the dealer. I surmised that the reason was that I would believe that I would realize better gas mileage and attribute it to having the car serviced.

I never thought of that!

If it’s true, though, it’s indefensible. It makes braking worse (smaller patch on the ground) and makes the tires wear unevenly.

Can’t be this. The bad PR if it were found out…

I’ve noticed that shops are tending to go high on tire pressure to ensure that the TPMS warning doesn’t trigger and cause a complaint. Very few customers actually check tire pressure after getting service done but 100% of those with the warning light coming on would come back.


I remember that EXACT scenario happening several years ago at the dealership

The tire guy . . . these guys only did tires and front end work . . . worked on the customer’s car in the afternoon and dutifully set the tire pressure as per the placard on the door jamb

The customer picked up their car that same afternoon

The next morning the customer’s tpms warning light was on, due to low tire pressure . . .

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Now THIS makes sense. Never considered it. Thanks.

The way I look at it is, if the vehicle is brought in for an oil change, and the TPMS light isn’t on, why add more air over spec?

Doesn’t make sense!


It could be they are so usede to working on Camtys that the tech thought the Venza had the same 35 pound spec. Setting the pressure 2-3 pounds more because the car had been driven would then make sense. I got 4 free tire rotations with Toyotacare. All 4 times they torqued the logs to at least 3 times the specified 85 ft lb. Complaining about it did no good, they still did it. They will actually rotate tires for free on any new car you buy from them for as long as you have it but I am nener going back there. The tire dealer I bought my tires from rotates them free and right to spec. and is 15 miles closer. I could still save time by doing it myself but letting them do it maintains the tire warranty.

We’ve talked about this on this very website in the past

If you torque the lug nuts to 85ft-lbs . . . the breakaway torque will be considerably higher

The first part regarding day and night time temps isn’t determinative because it’s the tire temp that matters, and that can be high from driving.
Thinking they should note where you live and estimate is asking a lot – and how would they know whether you drove around before going to the dealer?
As for touching the tires, how accurate do you think hands are at detecting specific temps (as opposed to hot, hot/very warm, warm, not so warm, cool, etc)?

Yes, but not so high that a 225 lb man should find them difficult to remove with a 3’ pipe over a 18" breaker bar. When I torque them to 85 lb they are easy to remove and when my tire dealer does it they are easy to remove and when a different Toyota dealer does it they are easy to remove.

I am not talking about a difference of 10,20, or even 40 ft lb.

I am talking of a removal torque of more than 250 ft lb. I may be an amateur but I have been doing this for many many years. I used to change tractor trailer tires on the road with a bottle jack and hand tools. These were torqued to 300 ft lb and were no more difficult to remove than the ones my Toyota dealer did on every visit, even when I complained about the previous visit. The service writer assured me this could not be happening because their techs used a torque stick. I said tell him to stop using it for a paperweight and put it on his air gun. I don’t need any pipe to remove the lugs when anyone else rotates the tires.

I could argue a little, but OK, I concede all your points.

Now tell me why the tires are intentionally filled six pounds over. In fact, as standard practice.

I’ve just pulled out the folder for the car. Except for those times I asked to not check the tires, the work order always shows 38 psi, not the 32 Toyota’s engineers require.

You didn’t mention the 3’ pipe over the 18" breaker bar earlier . . .

The ones in our fleet are torqued to from 450 - 500 ft-lbs . . . because that’s what our technical services said to do in a safety meeting, and also because it says so right on the lug nut

What size bottle jack were you using, by the way?

I just bought a 20 ton OTC . . . the more expensive blue one, not the budget gray “stinger” line . . . and I hope it’ll be good enough for home use and the occasional professional use

@Rod_Knox gave you the correct answer. Because people don’t check their tire pressure, ever, really. So over time the pressure stays above the recommended pressure. Higher pressure has no real down side except a bit more wear in the center of the tire offset by folks that let the pressure drop to 25 psi by never checking the pressure until the TPMS light comes on.

Your theory that braking suffers is mostly incorrect. A tire is not a balloon, contact patch does not just depend on air pressure.


My son works at Discount Tire. He tells me they are instructed to put 34psi in each tire regardless of anything.