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#2716268 - 08/16/12 10:24 AM what tire pressure to go by??
lucerne06 Offline


Registered: 03/07/09
Posts: 388
Loc: northeast
Should I go by the recommended tire pressure on my car label??? or do I go by the tire manufacturer recommendations??
And what if I put in 32 or 34 lbs instead of say 30 as called for on the car???

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#2716272 - 08/16/12 10:29 AM Re: what tire pressure to go by?? [Re: lucerne06]
Quattro Pete Offline


Registered: 10/30/02
Posts: 24665
Loc: Illinoistan
You go by the PSI on the car label, and can adjust a few PSI up from there.

The tire manufacturer only lists the MAX allowable PSI, but they have no idea what car you're going to mount their tires on.
_________________________
'02 530i (PU 5W-40)
'08 C300 4Matic (M1 0W-40)
'13 F700 GS (Spectro 15W-50)

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#2716279 - 08/16/12 10:36 AM Re: what tire pressure to go by?? [Re: lucerne06]
BrianWC Offline


Registered: 02/09/06
Posts: 6873
Loc: Louisiana
_________________________
2002 Honda CR-V EX AWD
2009 Honda Odyssey EX-L
2014 Ford Mustang GT

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#2716281 - 08/16/12 10:36 AM Re: what tire pressure to go by?? [Re: lucerne06]
4x4chevydude Offline


Registered: 05/06/09
Posts: 701
Loc: Northern IL
Go by the car and you can always add a few psi if you would like to
_________________________
2000 Chevrolet K2500 5.7 Old Body Style 6" Lift and 33" Tires 149k Miles

1998 Buick Century Limited 3.1 91k Miles

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#2716287 - 08/16/12 10:41 AM Re: what tire pressure to go by?? [Re: lucerne06]
sasilverbullet Offline


Registered: 08/22/04
Posts: 843
Loc: San Antonio, Tx
Before I give my .02, what yr/make/model of car and exactly what kind of tires? There are a lot of variations to my answer, all depend on the above information.
_________________________
70 Lincoln Mk III - Delo 15W-40
14 Honda Civic EX-L - Honda Synthetic 0W-20 for now
04 Nissan Titan - Amsoil 5W-30 XL

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#2716304 - 08/16/12 10:53 AM Re: what tire pressure to go by?? [Re: lucerne06]
HerrStig Offline


Registered: 08/24/11
Posts: 2929
Loc: Boston, MA
There is a direct relationship between "slip angle" which affects handling, tire wear, and ride quality. For a particular vehicle, there is usually a sweet spot, but that can vary depending on the actual tire on the car. The car companies have a tire pressure in mind which is a good compromise based on what they are supplying as OEM , but if you go up a rim size and width and fit a "performance" tire with a stiff sidewall and additional belts, it may be well off. The companies can't control what you replace OEM with. For example, overinflation usually affects a wider tire sooner than a narrow one. Radials don't telegraph underinflation to the driver as quickly.
In the racing world, tire pressure is set by using a "tire pryometer" which measures temps across the tread. The techs shoot for even heating. Hot spots point to inflation problems and/or alignment issues. We can't do that with a daily driver, so using an accurate gauge and getting a feel for adjustments is the best we can do. Don't just assume that more air is better.


Edited by HerrStig (08/16/12 10:54 AM)

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#2716308 - 08/16/12 11:00 AM Re: what tire pressure to go by?? [Re: lucerne06]
ARCOgraphite Offline


Registered: 05/17/09
Posts: 8353
Loc: N.H, U.S.A.
+1 on the sweet spot.
_________________________
2012 Honda Fit Sport 5MT, OC#5 30kmi- PP 5W20SN+Honda PLM A02 Filter
2011 Forester 5MT 5Door, OC#7 64Kmi-PU 5W20SN+TokyoRoki 130 Filter

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#2716325 - 08/16/12 11:14 AM Re: what tire pressure to go by?? [Re: lucerne06]
CapriRacer Offline


Registered: 02/22/03
Posts: 2439
Loc: Somewhere in the US
If you are using the same tire size as listed on the vehicle tire placard, then the pressure listed there is appropriate. If you are using a different size, then the pressure has to be recalculated. The calculation isn't difficult, but it involves the use of tire load tables which are not published on the internet. But I have a copy and am willing to it.

As others have indicated, what is written on the sidewall of the tire is NOT a recommendation.

And lastly, a few more psi is not a big thing. But be aware that ride quality suffers as pressure goes up.
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CapriRacer

Visit my web site: www.BarrysTireTech.com

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#2716327 - 08/16/12 11:16 AM Re: what tire pressure to go by?? [Re: lucerne06]
Rand Offline


Registered: 08/20/03
Posts: 7178
Loc: Akron,Ohio
I usually start at oem +2psi to +4 psi and adjust from there.

in my case its 32/30 which felt way to soft.

35/33.5 is pretty good.. and if I'm towing long distance I bump the back up to about 36-37

I had tried 36psi all around but it felt abit harsh.


Edited by Rand (08/16/12 11:17 AM)
_________________________
2011 Subaru Forester X Prem. 5MT

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#2716361 - 08/16/12 11:38 AM Re: what tire pressure to go by?? [Re: CapriRacer]
Rand Offline


Registered: 08/20/03
Posts: 7178
Loc: Akron,Ohio
is this similar to your load tables capriracer?

http://toyotires.com/tires-101/load-and-inflation-tables
_________________________
2011 Subaru Forester X Prem. 5MT

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#2716390 - 08/16/12 12:04 PM Re: what tire pressure to go by?? [Re: lucerne06]
ag_ghost Offline


Registered: 12/08/10
Posts: 372
Loc: SF Bay Area, CA
No arguments with the repiles; but like most people, I don't check the pressure as often as I should; so I always go above the listing on the door jambs. Wear from underinflation is far more common than the opposite.
_________________________
66 Mustang (289)-Valvoline VR1 10W30
63 Galaxie 500 (390)-Rotella T 15W40
00 Windstar-Chevron 5W-30
99 Accord V6-Chevron 5W-30

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#2716399 - 08/16/12 12:19 PM Re: what tire pressure to go by?? [Re: Rand]
buster Offline


Registered: 11/16/02
Posts: 29080
Loc: NJ
Originally Posted By: Rand
I usually start at oem +2psi to +4 psi and adjust from there.

in my case its 32/30 which felt way to soft.

35/33.5 is pretty good.. and if I'm towing long distance I bump the back up to about 36-37

I had tried 36psi all around but it felt abit harsh.


That is what I've always done too.

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#2716424 - 08/16/12 12:44 PM Re: what tire pressure to go by?? [Re: CapriRacer]
Donald Online   content


Registered: 03/21/04
Posts: 13169
Loc: Upstate NY
Originally Posted By: CapriRacer
If you are using the same tire size as listed on the vehicle tire placard, then the pressure listed there is appropriate. If you are using a different size, then the pressure has to be recalculated. The calculation isn't difficult, but it involves the use of tire load tables which are not published on the internet. But I have a copy and am willing to it.

As others have indicated, what is written on the sidewall of the tire is NOT a recommendation.

And lastly, a few more psi is not a big thing. But be aware that ride quality suffers as pressure goes up.


Best to keep same tire size and the PSI on the manual and/or door sill. Straying from that will cause problems from a balanced perspective (ride, handling, tire life, load capacity).
_________________________
2001 Jeep Grand Cherokee Laredo 4.0 - PP & M1
1999 Dodge Ram 2500 w/Cummins - Rotella T6 & M1
Amsoil ATF in both vehicles & Magnefine filter.

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#2716445 - 08/16/12 01:21 PM Re: what tire pressure to go by?? [Re: lucerne06]
Chris Meutsch Offline


Registered: 02/27/06
Posts: 1942
Loc: Cincinnati
I go 3psi over the plate's recommendation. 29 is 32 on the CR-V, 32 is 35 on the Pilot.
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"Please add more vagueness to this question and it will be that much easier to answer."
----TomYoung, 5/29/14

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#2716451 - 08/16/12 01:26 PM Re: what tire pressure to go by?? [Re: lucerne06]
wirelessF Offline


Registered: 10/04/07
Posts: 1217
Loc: Oahu, Hawaii
For some reason the rear PSI for rear tires on a empty pickup truck is too high. For my trucks they call for 35 PSI rear but I'll lower them down to 26 PSI. Before carrying a heavy load I'll air them back to 35 PSI or higher.
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For racing or off-road use only!

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