|11-16-2013 09:48 AM|
Again, I would not trust the chalk test by itself... by itself, without knowing what is reasonable for a specific tire size for a particular vehicle, the chalk test will just cause a tire to be under inflated. For a 30x9.50 tire when supporting a Wrangler, I'd use 29 around town with the vehicle carrying just 1-2 passengers. For highway use when the Jeep is loaded with gear/passengers, I'd raise it up to 32-33 psi max.
General guidelines on a tire's air pressure... One, there is no ideal PSI for a particular tire & tire size, that depends entirely on what weight that tire is carrying. The same exact tire and tire size will have different correct tire sizes which depend solely on the weight of vehicle it is carrying. Two, the correct tire pressure with any given vehicle weight is also dependent on the size of tire. For a Wrangler, 30 psi would be fine for a 30x9.50 tire but you'd only want 24-26 psi with a 35x12.50 Goodyear Wrangler MT/R when supporting the same weight. Generally speaking, the bigger the tire the lower the air pressure & visa-versa.
|11-16-2013 09:18 AM|
The door placard only lists for p205--33psi.
The manual has 2 different numbers. In the "tires" section inside the manual, it lists the 30x9.5 as 29psi; There's a quick-reference on the back cover that lists them as 33psi.
so...one of those, I guess.
I'll do the chalk test--how far do you have to roll to get the results?
|11-15-2013 10:23 AM|
|11-15-2013 09:16 AM|
|11-15-2013 08:34 AM|
|11-14-2013 11:19 PM|
|Jerry Bransford||Also pay close attention to what was said in post #11, the chalk and water "tests" are responsible for a lot of well intentioned but inexperienced Jeepers grossly understating their tires. For example, that 26 psi the person in post #16 above came up with grossly underinflated his 30" tires.|
|11-14-2013 10:43 PM|
|Water Dog||You will find that not only does your Jeep ride a lot better with properly inflated tires, but it will also drive and handle better.|
|11-14-2013 09:52 PM|
|capncraigagain||One thought comes to mind on the chalk test and tire inflation. The load, or weight on the tires will vary from front to rear because the most weight is up front, unless you are towing or have some heavy weight in the back. Therefore, front tires will need more pressure than rear, then adjust for adding weight.|
|07-21-2010 10:08 PM|
|GoldTJ||After reading some of these posts,I decided to try it on my crappy stock Goodyear GSA 30X9.50's.was running them @32 p.s.i.,went down to 26 p.s.i.-TREMENDOUS difference in ride quality.I never would have thought of this-thanks,all!The wife will not be happy with me buying new tires until I need them-can't wait for some real tires!|
|07-21-2010 06:41 PM|
|InfernoGirl||You just have to roll over it a few times. You can do the same thing by rolling thru water or dirt or mud, just look at the tires and see where the tread is touching. Like Jerry has mentioned numerous times, you don't want the entire tread to contact, but the majority of it. If you air them down enough for edge to edge contact they are under inflated.|
|07-21-2010 06:40 PM|
|lancetkenyon||I always liked 27PSI in my 31s and 32s. 35s ran great at 21 PSI, and my 37s liked 18PSI. My 39s don't see street very often(only in Moab), but they like 11-13PSI in the rocks.|
|07-21-2010 04:04 PM|
|07-21-2010 03:13 PM|
Wow, I didn't expect to receive so many replies so quickly! Thank you all for your input. I am going to go home today and do a chalk test on my tires. Thanks again...
|07-21-2010 02:50 PM|
|07-21-2010 02:50 PM|
|InfernoGirl||Do the chalk test, but i bet you'll find that right about 28 is where you'll want to be...|
|07-21-2010 02:12 PM|
|07-21-2010 02:07 PM|
|530ktm||I have 31 inch tires which are BFG's and I run 27 to 28 on the street.|
|07-21-2010 01:50 PM|
|DUCKIT||35" tires...... 25 psi on the street|
|07-21-2010 01:45 PM|
|4Jeepn||here is a good chalk link: Checking Tire Pressure - Determine Correct Pressure|
|07-21-2010 01:43 PM|
|07-21-2010 01:38 PM|
|Jerry Bransford||For 31" tires, I'd run 29 to 31 psi. Pretty close to 29 unloaded, 31 for when your Jeep is fully loaded. Those guys at the tire store were idiots for inflating them to 45 psi, they must be among the unschooled who think the correct tire pressure to run is what is molded onto the tire's sidewall. The pressure on the sidewall is only the tire's max safe pressure, not what should be run on the street. The correct tire pressure varies by the weight of the vehicle the tire is carrying so there is no one-single tire pressure that could ever be correct for all the various vehicle weights any particular tire might be carrying.|
|07-21-2010 01:32 PM|
|JDsDream||I'm running 27psi in my 31's. Nice smooth ride and no uneven tire wear.|
|07-21-2010 01:26 PM|
|Atthehop||You should do a chalk test but I run 25 psi in my 30x9.5's.|
|07-21-2010 12:46 PM|
I have a 2003 Jeep Wrangler and I just bought a new set of Kumho 31x10.50x15 All Terrain Tires. After I picked my Jeep up from the tire shop, it rode like a wagon from the wild west.I checked tire pressure and they were all around 45 psi.I lowered them all to around 38 psi and the ride was a bit better. My question is, with this size tire, what psi can I run that will have the best ride without causing the tires to wear prematurely?