Stock Tires 2007 Liberty Sport

BoyNamedSue · **Joined:** Mon Mar 12, 2007 3:32 pm **Posts:** 66

I'm confused about my tires. I've heard different things.
The sidewall of my tires says 44 max PSI, Goodyear Wrangler ST.
Is that the standard tire everyone else has with a Sport 4x4?

I already had a flat with only 600 miles, so I need an excuse to make them give me new tires. :lol:

tommudd · **Posted:** Wed Apr 18, 2007 10:48 pm

44 is the max amount that you want to put in a tire that size to carry the full load limit of the tire. Check on the drivers door or your owners manual for the right air pressure.

BoyNamedSue · **Joined:** Mon Mar 12, 2007 3:32 pm **Posts:** 66

tommudd wrote:

44 is the max amount that you want to put in a tire that size to carry the full load limit of the tire. Check on the drivers door or your owners manual for the right air pressure.

I should have clarified. I'm not asking about what pressure should I be at. I'm just wondering if I have the same tires as everyone else with a Liberty Sport. If I do I'll just go by the door jam which says 33psi cold.

SavageUrge · **Posted:** Wed Apr 18, 2007 11:41 pm

My '03 Liberty Renegade says exactly that - 33psi on the door jam, however the sidewall of the Goodyear SR-A's that came with the Jeep said 44psi. DO NOT GO BY THE DOOR JAM STICKER! ALWAYS INFLATE YOUR TIRES TO THE MAXIMUM RECOMMENDED PSI ON THE SIDEWALL WHEN DRIVING ON-ROAD. Don't mean to yell, but I want to stress that point. A tire that is under-inflated by 2-3 psi is 3 times as likely to cause a dangerous performance failure than a tire that is 5 psi overinflated! Of course this whole theory goes out the window when off-road, where the idea is to maximize traction by deflating the tires to create more surface area for them to grip with.

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

SavageUrge wrote:

My '03 Liberty Renegade says exactly that - 33psi on the door jam, however the sidewall of the Goodyear SR-A's that came with the Jeep said 44psi. DO NOT GO BY THE DOOR JAM STICKER! ALWAYS INFLATE YOUR TIRES TO THE MAXIMUM RECOMMENDED PSI ON THE SIDEWALL WHEN DRIVING ON-ROAD. Don't mean to yell, but I want to stress that point. A tire that is under-inflated by 2-3 psi is 3 times as likely to cause a dangerous performance failure than a tire that is 5 psi overinflated! Of course this whole theory goes out the window when off-road, where the idea is to maximize traction by deflating the tires to create more surface area for them to grip with.

The theory goes out the window anyway. The 44psi on the tire is the MAXIMUM that the tire is rated to-- you cannot put more air than that safely in the tire. The maximum does not mean the recommended-- that is determined by tire design and construction AND by the wieght and suspension type on your vehicle. Filling your tire to less than the maximum posted on the sidewall is not underinflating it. Underinflating it would be less air than recommended for the vehicle wieght-- as posted in the door jamb and in the owners manual.

Also, if you look at the rest of the fine print on the P.O.S. Goodyear SRA's you will note the tire states to go by the vehicle's owner manual and placard instructions for air pressure, not to use the MAXIMUM rated for the tire as a minimum.

35 psi should be as high as you would want to go for a gas KJ. For a diesel I get the best economy out of 40 psi... I am not concerned with the tire life or ride, as the tires ride like crap and wear poorly to begin with.

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

BoyNamedSue wrote:

tommudd wrote:

44 is the max amount that you want to put in a tire that size to carry the full load limit of the tire. Check on the drivers door or your owners manual for the right air pressure.

I should have clarified. I'm not asking about what pressure should I be at. I'm just wondering if I have the same tires as everyone else with a Liberty Sport. If I do I'll just go by the door jam which says 33psi cold.

Yes, you unfortunately have the sorry stock tires.

BoyNamedSue · **Joined:** Mon Mar 12, 2007 3:32 pm **Posts:** 66

Is it strange that I would have a flat tire after only 800 miles on brand new, fairly large tires, with good tread and the tire shop only found a hole, but nothing in it?

I've had many flats in the past on smaller tires, but there was always a nail in them. Just wondering. Maybe someone in my neighborhood doesn't like my new Jeep.

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

BoyNamedSue wrote:

Is it strange that I would have a flat tire after only 800 miles on brand new, fairly large tires, with good tread and the tire shop only found a hole, but nothing in it?

I've had many flats in the past on smaller tires, but there was always a nail in them. Just wondering. Maybe someone in my neighborhood doesn't like my new Jeep.

No telling with this tire. I had to replace one of these at 10,000 miles when a thorn went through the sidewall. Yeah... a little itty bitty thorn. Some tire. When I saw the tire off the rim I could not believe it... the tires on my mountain bicycle had thicker sidewalls.

BoyNamedSue · **Joined:** Mon Mar 12, 2007 3:32 pm **Posts:** 66

Quote:

No telling with this tire. I had to replace one of these at 10,000 miles when a thorn went through the sidewall. Yeah... a little itty bitty thorn. Some tire. When I saw the tire off the rim I could not believe it... the tires on my mountain bicycle had thicker sidewalls.

You are filling me with confidence about these Goodyears. I'm broke, so I'm stuck with them. I couldn't believe I already had a flat though. They look huge compared to the little tires I had on my old S10. I wish I could have talked to the tire shop more about what this hole looked like, but they were too darn busy and did it for free. Didn't want to bother them.

AfricaJeep · **Posted:** Thu Apr 19, 2007 3:12 am

SavageUrge wrote:

My '03 Liberty Renegade says exactly that - 33psi on the door jam, however the sidewall of the Goodyear SR-A's that came with the Jeep said 44psi. DO NOT GO BY THE DOOR JAM STICKER! ALWAYS INFLATE YOUR TIRES TO THE MAXIMUM RECOMMENDED PSI ON THE SIDEWALL WHEN DRIVING ON-ROAD. Don't mean to yell, but I want to stress that point. A tire that is under-inflated by 2-3 psi is 3 times as likely to cause a dangerous performance failure than a tire that is 5 psi overinflated! Of course this whole theory goes out the window when off-road, where the idea is to maximize traction by deflating the tires to create more surface area for them to grip with.

Is it not dangerous inflating a tire to the max psi, especially when doing long distance driving? As far as I understand, the air in your tire expands the hotter it gets. So over long distances the pressure inside your tire increases.

I used to do lots of 860 mile journeys and one thing I learnt was that you only fill your tires at the beginning of the journey and never during (unless you get a puncture of course). We measure pressure in bars (is psi pound per square inch?), and when I fill up after about 300 miles the tire pressure is normally 2 - 3 bars higher. This may be an urban myth, but I was told that adding more air could result in a blow out.

sleeve84028 · **Posted:** Thu Apr 19, 2007 7:34 am

I am not sure what would happen if you ran at the max PSI for more tahn a couple hours. What I do know is that a tire inflated to the maximum PSI means that you are only riding on the center section of the tread. This leaves a minimal contact patch between you and the road which could lead to:

1) reduced hydroplane resistance
2) reduced cornering stabilitity
3) increased wear since only a portion of the tire is taking the suspension load

If the numbers on the door jam (mine might be in the glovebox) didn't mean anything why would any manufacture spend the time and money to put that sticker on?

A tire could blow if it was inflated to be as stiff as a rock. I've had it happen on a bicycle - but never a car tire.

Edit: I also forgot to mention: It is not too uncomon to get a hole in your tire and then have the object come flying back out as you drive down the road. The stock goodyear tires are pretty cheaply made and seem to be a little thinner than other tires so that might have lead to your failure.

tulsa · **Posted:** Thu Apr 19, 2007 7:56 am

Sue,
I have the same tires you have on my 05 CRD, not my first choice, but have 20K miles and plenty of tread left. I inflate to about 40 psi because that is where I am happy with the handling. Looks like the ST's will be good for 50K with my driving style, been good in snow, but need to be very careful when cornering on wet streets. I prefer Michelin but have seen sidewall punctures with them driving in soybean stubble.

SavageUrge · **Posted:** Thu Apr 19, 2007 1:29 pm

Quote:

Also, if you look at the rest of the fine print on the P.O.S. Goodyear SRA's you will note the tire states to go by the vehicle's owner manual and placard instructions for air pressure, not to use the MAXIMUM rated for the tire as a minimum.

35 psi should be as high as you would want to go for a gas KJ. For a diesel I get the best economy out of 40 psi... I am not concerned with the tire life or ride, as the tires ride like crap and wear poorly to begin with.

I got 52,000+ miles and 21mpg out of my stock Goodyear SR-A's with them inflated to 44psi all the time. In fact I am considering GOING BACK to this tire becasue I never had any problems with them at all. See my signature - I HATE the "highly recommended" Firestone Destinations. Long story, but I DO NOT recommend these tires if you do a majority of on-road driving!

Big D · **Joined:** Mon Jun 05, 2006 10:08 pm **Posts:** 349

How are your teeth?..just kidding...At 44lbs that's high.

It all depends what you want. If you factor in comfort, treadwear and handling, I would go by the manufactures recommended spec.

As for driving at max pressure, you wouldn't really get the tire to warm up properly. A tire to function correctly must be warmed up to it's optimum temperature. The pressures posted on the door jam are a compromise between empty and fully laden vehicule, while looking at comfort, treadwear and handling. If you drive empty all the time, believe it or not, the optimum tire pressure is actually slightly lower than what's posted on the door jam.

BoyNamedSue · **Joined:** Mon Mar 12, 2007 3:32 pm **Posts:** 66

Quote:

The pressures posted on the door jam are a compromise between empty and fully laden vehicule, while looking at comfort, treadwear and handling. If you drive empty all the time, believe it or not, the optimum tire pressure is actually slightly lower than what's posted on the door jam.

That's pretty interesting. I just put mine at 35psi yesterday, because I usually drive solo with no load, so I thought a couple PSI higher than the door jam would be better. But you're saying maybe I should be a couple lower than the door jam. No big deal, a couple psi higher, lower, whatever......... but interesting.

Donkeykong · **Posted:** Thu Apr 19, 2007 3:07 pm

AfricaJeep wrote:

...and when I fill up after about 300 miles the tire pressure is normally 2 - 3 bars higher....

Do you mean 2-3 psi higher?

2-3 bar higher would be 29.4 to 44.1 psi higher. :lol:

(just saw africa in your name, and figure that you use the metric standards for pressure because AFAIK, you guys use the metric system for units, not the SI.)

I always go by the door pressure, at the gas station a mile from my house.
I can't wait to get rid of my OEM tires.
-Mark

StarDreamer.us · **Joined:** Fri Oct 06, 2006 9:15 pm **Posts:** 63

05 CRD Sport with factory tires and been running 40 lbs all around since day one. A little harder ride, but that has not been a problem. This is a truck right? Mostly highway miles.

SavageUrge · **Posted:** Thu Apr 19, 2007 4:29 pm

Everyone here obviously has "heard" this and that about tires from their friend, brother, father-in-law, mechanic etc. I personally have read reports from manufacturers that if you are driving on road, then the max psi is where you should be. This is considered "full" and will give you optimum tread-wear, mileage and traction regardless of whatever else you've "heard" including "warming them up". Only people running slicks on a race car need to warm up their tires, and that's to provide maximum tackiness for a solid launch off the line and cornering. Those tires are designed for that, as passenger tires are designed to be run at the psi on the sidewall. I'm not trying to be critical of anyone, I simply do not want to see anyone get hurt as a result of an underinflated tire. With a tire that says 44psi on the sidewall inflated to 33psi, imagine you had to swerve very quickly or perform any other evasive maneuver that required quick steering. Your tires would act like a jelly donut. Besides the fact that they could flex almost to the point of coming detached from the rim, in which case you'd lose all control! I'm sure you've seen an accident on the side of the road, where the tire is off the rim on one of the vehicles? This is almost assuredly because the tire was underinflated, so it gripped and flexed too much for the bead/sidewall to handle as the vehicle was sliding/skidding. Food for thought.

tommudd · **Posted:** Thu Apr 19, 2007 5:53 pm

25 lbs of air would be underflated, 40/44 is WAY OVER inflated unless you are hauling 10000 lbs or something. Not to start anything but please do some reading on proper tire pressures. The first 10 years of my working life was spent in tire shops, I just can not believe some of the GOOD advice that is being told on here.

Has anyone ever seen the chaulk test done on tires? thats one way to come up with the best wear pattern, not running 44 lbs and riding on only the center ribs of the tire.As far a anything going through a tire after 2 hours on the road any tire is like butter to cut through trust me I have seen things go through tires that you wouldnt believe

SavageUrge · **Posted:** Thu Apr 19, 2007 6:05 pm

I to, have spent a fair share of my working life dealing with tires, wheels etc., however at this point I digress. I don't come on this site to get into heated debates about what is right, what is wrong and what people think they know. I'm simply attempting to help people to stay safe for their sake and that of their families by getting the word of the manufacturers out. I'm 10-8, on the side, reading the mail.

Stock Tires 2007 Liberty Sport

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