Follow manual and fill to 29 PSI or listen to mechanic?

I have a 2019 TRD Sport, which came with Toyo Open Country A30 tires (265/65R17). I just had Michelin LTX A/T 2 tires installed. The door frame says the tires should be filled to 29 PSI, which is what I always stuck to. The new tires say "Max PSI 44" on the side. The mechanic who installed them filled them to 40 PSI. The tires are the same size as stock (265/65R17). Do I continue to follow the manual and fill them to 29 PSI or was the mechanic correct to fill them to 40? The truck is completely stock. Thanks for your help.

 

If stock tire size and load stick to what the jamb says. Dealerships and shops set them to a fixed pressure because they're lazy. I found my truck to ride really rough when I got new tires and found they were set to 40psi. Dropped them down to 29psi and they ride nice and smooth now.

 

Thanks, I'll deflate them now

 

I bet it will ride much nicer. Most shops have an automated tire pressure filler that sets them to the preset pressure the shop put it to. This is why most people end up with 40psi. They are doing to customer a disservice. Even the oil change shop I worked at as a teen was adamant that we adhere to what the door jamb decal states for this very reason.

 

Same thing happens when I go to Discount tire to have my tires rotated. I always drive it home, allow the tires to cool and deflate to what is listed on the door.

 

Every brand and model of tire is different. 2 different models of tires will wear and perform differently at the same PSI on the same truck. The door jamb sticker is a good starting point that will work with whatever tire and at least get you from point A to point B. But, the optimum air pressure for each tire model really needs to be determined by the contact patch (how much of the tread os making contact with the road), and the tread wear over time. Over inflating will wear down the middle of the tires faster, and under inflating will wear the edges of the tires faster. More PSI = better MPGs, but will ride stiffer. Less PSI = worse MPGs, but a softer ride.

If you start at what the door jamb says, you can adjust from there. I have 265/75R16 Falken Wildpeaks in standard load, and when I set em at 30 PSI (cold), I was getting noticeable wear on the edges after ~1000 miles, so I brought them up to 35 PSI (cold) and they are all wearing evenly now (over the last 15K mi.). My average MPGs went up by about 1.5 too and the ride is still nice, so for my tires, 35 PSI on my truck is undeniably the sweet spot.

 

Please someone que the "chalk test" nonsense e so I can point out again how it doesn't work. I will never understand why people keep doing it.

In any case, 29 cold is the lowest you want to go. If you want longer tire life and better gas mileage, go back to 40 or even 44. Like that cushy ride, keep them at 29. I would be shocked if you could actually tell the difference between 14psi.

 

People really drive around with 40+psi tires? You’d feel every crack in the road

 

I'm jealous. I've been oogling those Michelins for a while now and can't bring myself to get rid of the OEM A30s with 8k miles on them. How do you like them so far?

 

Curious if you noticed driving at 40 psi, then again @ 29 psi to see what your preference is????

Myself I upsized my tires, and still prefer 30 summer, 32 winter.

 

29 felt soft but also felt a bit of a roll / sway on turns especially at highway speeds

40 does feel firm but more responsive in handling.

I keep mine in the high 30’s. So far I’ve had even wear with regular rotations.

I change my psi a little bit depending on the season. Higher in winter and a bit lower in summer

 

I run 40 on my E rated. On a truck as light as the taco with a heavy load thick sidewall tire the difference between in ride between 32 an 40 is absolutely nothing.

 

I keep my psi at 32 all around. It gets to 33/34 when driving and drops to 29 in cold weather

 

Well you should be shocked already as a number of people have already posted the handling difference they observed with the tire pressure too high at way less than a 14psi difference.
My Access Cab 4 cylinder is the lightest of the models. After dealer service, on the drive home it was a harsh ride, I felt every bump in the road and the steering felt a bit wandering and I knew something was wrong. After the tires cooled off checked pressure and dealer had at 37-38 psi. Door sticker is 32psi for mine and I set pressure back to that (which is where I always keep them) and ride and handling was back to normal with steady steering.
That’s only a 5-6 psi difference.
Those with heavier truck models and mods or E rated tires may have a different experience but I don’t care who you are if you can’t even tell a 14psi difference I’m just not gonna let you put air in my truck.

 

I have put on different tires (E) and I ride around at 38 for trips. It helps gas mileage. It is a bit rougher. Around the city at 30. Down to 20 for off-roading.

 

Well you should be shocked already as a number of people have already posted the difference they observed with the tire pressure too high.
My Access Cab 4 cylinder is the lightest of the models. After dealer service, on the drive home it was a harsh ride, I felt every bump in the road and the steering felt a bit wandering and I knew something was wrong. After the tires cooled off checked pressure and dealer had at 37-38 psi. Door sticker is 32psi for mine and I set pressure back to that (which is where I always keep them) and ride and handling was back to normal with steady steering.
That’s only a 5-6 psi difference.
Those with heavier truck models and mods or E rated tires may have a different experience but I don’t care who you are if you can’t even tell a 14psi difference I’m just not gonna let you put air in my truck. [/QUOTE]
Why not? What do I care what psi you run? You ask for 10 I’ll give you 10. You want 60? 60 it is. That’s your call to make for yourself and means nothing to me. You don’t ask for a preference you get factory recommendations.

 

I run mine 30 psi. Same tire and size.

 

You went from a P-metric P265/65/17/110 to a euro-metric 265/65/17/112. Although they are the same size, they have different load ratings; as well as different inflated load capacities for any given psi. You would only continue to follow the manual if you replaced the tire with a tire that has the exact spec as your factory tire.

The P265/65/17/110 has a load capacity of 2,149 lbs @ 29 psi.
The 265/65/17/112 has a load capacity of 2,149 lbs @ 30 psi.

 

I thought the 29 was kinda lame so I keep em at 32/33

 

This.