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Discussion Starter · #1 · (Edited)
TIRE PRESSURE INFORMATION
A number of you have been telling me in private, or posting publicly, that your dealers have been seriously over-inflating your car's tires, and telling you all sorts of reasons for it (one was over-inflated by 12psi... wow).

So, today, I had a chat with Grant at Subaru of America, Inc. about this. Grant is actually the very first SoA person I ever spoke to, way back in 2013, and I've had the pleasure of chatting Subie stuff with him off and on for over six years now.

Here's the answers:
"We would absolutely recommend that you go by the inflation information on the vehicle placard."
So, there you have it!
■ 20" OEM wheels: 33psi (32psi if your door says that)
■ 18" OEM wheels: 35psi

Tires that match OEM specs should also be inflated as per the door placard. For tires of differing sizes, I'd contact your local performance tire professional or @Discount Tire (they're who I got my setup from) or Tire Rack.

And, the dealers will be contacted regarding the proper information and procedures.
"I will gladly pass on your comments about the tire pressure internally. They will also be shared with our retailers."

So, hope that helps all of you looking for the proper answers.
#SubaruAmbassador #SubaruAmbassadorRobert #SubaruAscent #tirepressure
 

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Running a higher pressure doesn’t effect anything if the tires are rated for it. The tire company’s will tell you this. I don’t know what the stock tires max pressure are though and I’m sure the 18 and 20 are different.
 

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Robert:
W/ your aftermarket wheel setup, what tire pressure do you normally set it at? I saw your a pic of the guage and yours were like 40psi+

Mine was 45psi on all wheels when I got it from the SOA. I don't think my car was inspected by the dealer.
 

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Discussion Starter · #4 ·
Robert:
W/ your aftermarket wheel setup, what tire pressure do you normally set it at? I saw your a pic of the guage and yours were like 40psi+

Mine was 45psi on all wheels when I got it from the SOA. I don't think my car was inspected by the dealer.
45psi seems to be what they're shipped at. Checking tire pressure is part of the PDI, but I suspect they just missed that step.

I have 31% more sidewall than the 20" stock I was running, and actually run about 38 psi. I drive very "New Yorker" on our very windy highways with very short exit ramps, on beefy tires, so, they heat up a bit more than a regular tire would for most drivers, hence, when my car sends mileage and tire info, it's after high speed exits on sharp ramps, just a couple miles before parking.

My 20's, I ran at 33psi, for the entire 2,403 miles I had them on, which is what @Liberty Subaru delivered the car to me at, perfectly matching the door placard.
 

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TIRE PRESSURE INFORMATION
A number of you have been telling me in private, or posting publicly, that your dealers have been seriously over-inflating your car's tires, and telling you all sorts of reasons for it (one was over-inflated by 12psi... wow).

So, today, I had a chat with Grant at Subaru of America, Inc. about this. Grant is actually the very first SoA person I ever spoke to, way back in 2013, and I've had the pleasure of chatting Subie stuff with him off and on for over six years now.

Here's the answers:
"We would absolutely recommend that you go by the inflation information on the vehicle placard."
So, there you have it!
■ 20" OEM wheels: 33psi (32psi if your door says that)
■ 18" OEM wheels: 35psi

Tires that match OEM specs should also be inflated as per the door placard. For tires of differing sizes, I'd contact your local performance tire professional or @Discount Tire (they're who I got my setup from) or Tire Rack.

And, the dealers will be contacted regarding the proper information and procedures.
"I will gladly pass on your comments about the tire pressure internally. They will also be shared with our retailers."

So, hope that helps all of you looking for the proper answers.
#SubaruAmbassador #SubaruAmbassadorRobert #SubaruAscent #tirepressure
I am having my tires rotated right now at Discount Tire and had to insist that they inflate to 33 manufacturer spec. His response was okay but they usually inflate 2-3 lbs higher in Denver due to elevation. My pressure gauges have always indicated 33 or within one lb.. I do not understand why I always get pushback from Discount Tire on inflation
I have been a customer for 20 years and whenever I came in for my other vehicles air check it was the same issue. They always want to overinflate. I wonder what documentation and training they receive.
 

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Could the tire inlfation contribute to the few blowouts that have been posted on the forum, I think mainly related to the 20 in wheels?
 

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Could be that’s what he learned for the reason...
Air heats up as it’s compressed so if they add several pounds to a tire up to 33psi, it’ll cool and then be under inflated. That’s my reasoning for always adding an extra psi or two anyway.
 

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I would absolutely go with Subaru's recommendation. I had normally used 33PSI with the 20s and I everything was fine. I had an oil change at the dealer about 1200 miles ago and they put the tires at 35PSI. I left it that way to observe any differences. The ride was subtly more sesnsitive to imperfections on the road. I put them back to 33PSI yesterday and the ride is definitely more plush. I noticed the same thing with my Outback.
 

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'beef, I personally prefer the slightly more sensitive feel of 35 psi, but I'm also used to the same from Michelin Defender LTX at 38 psi on the Grand Cherokee I previously drove. I would also always recommend folks go with the recommended tire pressures in general, but I also accept that some of us do like a pound or two harder for various reasons. There are some tires that work better that way, too. No way would I suggest anyone over-inflate well beyond that, however. That can cause safety and tire wear concerns.
 
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My Ascent was delivered to me at 45 PSI and it's down to 40 PSI when I checked it last weekend.
That's the way it leaves the factory for the "trip" to your dealership. Sounds like they forgot to change it before "pickup" by you. Somewhere on this site is a checklist of things to check, and that was one of them. If you look a the label on your door, I bet it sure doesn't show 45 PSI
 

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We picked our car up at night. When I went out to the car the next morning I saw the green air stem caps and I was disappointed ( nitrogen). I also checked and the pressure was at 42, 42,42,38, so I dropped them all to 36 which is where I like to keep it. When the time comes to swap out to my winter wheels and tires I'll have the OEM tires deflated and reinflated with air.
 

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Why would you be disappointed that they are nitrogen filled? Nitrogen doesn't heat up as much and helps prevent the tires from oxidizing from the inside which helps the rubber last longer. It's an upgrade.
 

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That's the way it leaves the factory for the "trip" to your dealership. Sounds like they forgot to change it before "pickup" by you. Somewhere on this site is a checklist of things to check, and that was one of them. If you look a the label on your door, I bet it sure doesn't show 45 PSI
My local dealership forgot a lot of things. I found bits of plastic all over the car, and one of the fog light covers was missing and they haven't ordered the replacement despite being asked several times. My local dealership is a disappointment.
 

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I am having my tires rotated right now at Discount Tire and had to insist that they inflate to 33 manufacturer spec. His response was okay but they usually inflate 2-3 lbs higher in Denver due to elevation. My pressure gauges have always indicated 33 or within one lb.. I do not understand why I always get pushback from Discount Tire on inflation
I have been a customer for 20 years and whenever I came in for my other vehicles air check it was the same issue. They always want to overinflate. I wonder what documentation and training they receive.
Is there a tendency at higher elevations to add a couple of PSI in compensation for when you drive to lower elevations? Just a guess.
 

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Running a higher pressure doesn’t effect anything if the tires are rated for it. The tire company’s will tell you this. I don’t know what the stock tires max pressure are though and I’m sure the 18 and 20 are different.
The tires will be fine up to the rated PSI and will not explode or anything.

But over-inflating a tire for the weight it is carrying will reduce your tire's contact patch and therefore your grip. The tire will wear more in the middle of the tire. The ride will be harsher. Potholes and other road hazards will be more jarring. You will lose ride comfort and wear out your tires quicker which will cost $$$. Any good tire company will tell you this.

I usually have my tires about 2PSI above the placard. I get a slight boost in mpg without the harsh ride or uneven wear.
 

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Discussion Starter · #18 ·
Is there a tendency at higher elevations to add a couple of PSI in compensation for when you drive to lower elevations? Just a guess.
I just did 8,400 miles without touching my air pressure once. That started at 19.7 feet above sea level on Long Island, and includes 5,000 feet in Colorado Springs, 11,990 feet at Loveland Pass, 6,400 feet at Moro Rock and 8,800 feet in Yellowstone.

If I lived at Loveland Pass, I'd probably inflate by a whopping 2-3 psi more.

You don't compensate by over-inflating. You compensate by inflating to recommended at the altitude you predominantly travel in, or for the higher altitude you live in (eg: my fictitious example of living at Loveland Pass), so, in my "IF", if I lived there, I'd inflate to normal psi, which would be a little higher on the days I visited lower areas.
 

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If I lived at Loveland Pass, I'd probably inflate by a whopping 2-3 psi more.
But that's all the initial comment was about- adding 2-3 psi at higher elevations. I think the relative pressure of the tire will decrease as you descend to lower altitudes at which atmospheric pressure is higher.

I'm not saying it's important (I never worried about it when I lived in the New Mexico mountains). Just curious about the rationale for the Denver Discount Tire tendency mentioned above.
 

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Discussion Starter · #20 ·
But that's all the initial comment was about- adding 2-3 psi at higher elevations. I think the relative pressure of the tire will decrease as you descend to lower altitudes at which atmospheric pressure is higher.

I'm not saying it's important (I never worried about it when I lived in the New Mexico mountains). Just curious about the rationale for the Denver Discount Tire tendency mentioned above.
For people who regularly travel up and down mountains and spend time at higher and lower elevations (and I know how easy that is from my trip), they "over inflate" a bit. 2-3 psi seems normal amount and meets a wide range.

The purpose is so when the person travels to a lower altitude, they don't have low tire pressure.

But, conversely, they can simply inflate to normal psi at the lower altitude and be done. So, they aren't really over-inflating. They're inflating for the lower elevation, so the person's tire pressure is always at least normal psi.

Check this out:

It's when some of these places inflate to 40psi, or leave it at the shipping 45 psi that things get problematic.
 
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