Recommended PSI?
JK Super Freak
Joined: Jun 2009
Posts: 1,312
Likes: 1
From: Cashton, WI
WOW !! You can always count on Jpop for a great factual response !
Actually the text book way would be to use the door placard data along with the Service Description of the OEM tire. The Service Description is a 3 number code as to how much weight a tire can support at a given inflation rate, generally often followed by a letter for the tires speed rating.
Using an ETRTO chart you can cross reference the supported weight of the OEM tires and find a corresponding inflation rate for the service description of your new tires. It's pretty simple, the worksheets and charts are on just about every tire manufacturers website and ETRTO charts are readily available if you want to download them.
While I don't believe this cross referencing is the end all, at least you know where the vehicle and tire manufacturer recommend that you are to match stock spring rates and promote your safety. It's also important to note in the case you have any warranty issues with your tires.
I use the ETRTO charts to find my initial inflation rates and then move on to the chalk test that is the favored way to determine inflation rates by so many on this forum. Generally this will tend to be lower than the ETRTO charts suggest and I use the difference as the window of where I want my tires to be, promoting ride quality and handling.
Some description on what the chalk test entails. Use a piece children's sidewalk to draw a line across the tread width. Move your vehicle far enough to get a few rotations of the tire and inspect where any chalk remains. Chalk remaining on the outside of the tread suggests you should reduce your inflation rate while chalk remaining towards the center suggests you should increase your inflation pressure.
As for off road use, this is mostly a matter of personal preference but most will find a comfort level with between 12 to 20 psi, often lower with bead locks. Different tires will respond differently and for example on my former Toyos I would drop them to around 12 psi because of the extra sidewall support and my Goodyear MTRs with Kevlar I run at 16 psi.
Hope that helps!
Using an ETRTO chart you can cross reference the supported weight of the OEM tires and find a corresponding inflation rate for the service description of your new tires. It's pretty simple, the worksheets and charts are on just about every tire manufacturers website and ETRTO charts are readily available if you want to download them.
While I don't believe this cross referencing is the end all, at least you know where the vehicle and tire manufacturer recommend that you are to match stock spring rates and promote your safety. It's also important to note in the case you have any warranty issues with your tires.
I use the ETRTO charts to find my initial inflation rates and then move on to the chalk test that is the favored way to determine inflation rates by so many on this forum. Generally this will tend to be lower than the ETRTO charts suggest and I use the difference as the window of where I want my tires to be, promoting ride quality and handling.
Some description on what the chalk test entails. Use a piece children's sidewalk to draw a line across the tread width. Move your vehicle far enough to get a few rotations of the tire and inspect where any chalk remains. Chalk remaining on the outside of the tread suggests you should reduce your inflation rate while chalk remaining towards the center suggests you should increase your inflation pressure.
As for off road use, this is mostly a matter of personal preference but most will find a comfort level with between 12 to 20 psi, often lower with bead locks. Different tires will respond differently and for example on my former Toyos I would drop them to around 12 psi because of the extra sidewall support and my Goodyear MTRs with Kevlar I run at 16 psi.
Hope that helps!
JK Junkie
Joined: May 2009
Posts: 3,074
Likes: 1
From: Denton, TX
I think I'm going to bump mine up to 40 as well, I'm at 36 for now. Didn't notice much ride difference, the rolling resistance is brutal on these things.
JK Enthusiast
Joined: Feb 2010
Posts: 459
Likes: 0
From: Visalia, Ca
Re: Recommended PSI?
I'm also running "D" rated tires (33 x 12.50) my mileage sucks anyway so I run lower pressure for the crappy bumpy roads I have to drive. I'm @ 24, I've ran higher but its bone jarring on some of our potholes.
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JK Newbie
Joined: May 2009
Posts: 34
Likes: 0
From: U.A.E. Dubai
Sorry but that's way to low psi I drive in the desert alot and would never go below 16 psi I did once before and the tyre came off the rim