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Old 11-06-2012, 07:31 PM   #1
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Does tire pressure really effect MPG that much

Been running 45lbs on my 97 TJ... yeah it help on gas but man it rides hard. So I couldnt take it anymore and decided to drop tires down to 35 still higher then normal. Well rides nicer but feels lower and more sluggish. Does that make any sense ?

P Scott

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Old 11-06-2012, 07:34 PM   #2
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It does make a difference but I doubt you are actually feeling anything different. I'm not calling you crazy by any means and I'm not saying that what I'm about to say is what is happening but most likely it's in your head. But who knows you did make a big jump in tire pressure so you might be feeling some sluggishness

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Old 11-06-2012, 07:48 PM   #3
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More air in the tire equals less rolling resistance and also a firmer ride. 28 psi would provide you a good compromise of the two.
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Old 11-06-2012, 08:19 PM   #4
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I like running a few lbs above normal, and yes it does help mpg. But 45 PSI??? I would be very, very careful running cold tire pressures that high, especially in the summer. It wouldn't take much highway driving to push that pressure well over 50 or maybe 55.

Another concern is traction in wet weather, and you will also wear out the center of your tires long before the edges.
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Old 11-06-2012, 08:25 PM   #5
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Originally Posted by noz34me View Post
I like running a few lbs above normal, and yes it does help mpg. But 45 PSI??? I would be very, very careful running cold tire pressures that high, especially in the summer. It wouldn't take much highway driving to push that pressure well over 50 or maybe 55.

Another concern is traction in wet weather, and you will also wear out the center of your tires long before the edges.
X2 was distracted with answering his question and forgot to say something about 45psi which is wayyyy high.
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Old 11-10-2012, 02:45 PM   #6
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My tires say max PSI 50, which seemed incredibly high to me, so I ran them at 35-37 PSI and my gas mileage as well as how the Jeep drove was HORRIBLE. A few weeks ago I aired up to 45 PSI and my gas mileage increased by appx 50 miles/tank and my power and just overall drive-ability has increased. So I'd say yes, tire pressure can make a huge difference
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Old 11-10-2012, 05:08 PM   #7
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I run my 30s on 15s at 35psi street and I wouldn't run them any higher then that. It seems to be the best comp between ride and mpg.
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Old 11-10-2012, 05:23 PM   #8
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Quote:
Originally Posted by 99tjnc View Post
My tires say max PSI 50, which seemed incredibly high to me, so I ran them at 35-37 PSI and my gas mileage as well as how the Jeep drove was HORRIBLE. A few weeks ago I aired up to 45 PSI and my gas mileage increased by appx 50 miles/tank and my power and just overall drive-ability has increased. So I'd say yes, tire pressure can make a huge difference
Max psi on the side of your tire is just that, not the recommended psi you should run the tire at. Jeep specs around 30 psi for stock tires
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Old 11-10-2012, 05:28 PM   #9
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The more air you put into the tire, the less of the tire you're using to drive on, steer with and stop with. Put about 28 psi, as mentioned earlier, in the tires and you'll get better handling, stopping and ride. Your tires will last longer too.
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Old 11-12-2012, 12:51 PM   #10
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the side of my door on my 2012 jeep stock tires says 35psi
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Old 11-12-2012, 02:59 PM   #11
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Quote:
Originally Posted by Abnmarine
More air in the tire equals less rolling resistance and also a firmer ride. 28 psi would provide you a good compromise of the two.
Yup what he said. HOW you drive makes much more of a difference. I just got 22MPG by driving like an old man. I shift before 2k and don't go above 55MPH.
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Old 11-15-2012, 06:24 PM   #12
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Tires are rated at cold air pressure .
So if it says max air is 50 that will be 50 psi cold and almost every tire will
say max pressure is ..... cold
The higher the pressure will give a firmer ride, you will feel more vibration in the steering whee, slightly reduced tire life, but you will increase your mpg .
I like running mine at 40psi on the street and i air down off road to match the type of off roading i am doing .
Then I air back up before I hit the road.
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Old 11-15-2012, 09:10 PM   #13
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good read
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Old 12-08-2012, 12:10 AM   #14
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Originally Posted by freestate23
good read
I would like to drop my pressure lower than 35 but the tpm light in the dash lights up at 35 and below.
On my 2013 I have been trying different pressures to find a good on road ride since I am taking the family on a round trip from chicago to Florida to visit relatives. the dealer gave it to me with 40 and wow it was harsh. I dropped to 35 and it is better but 30 -32 seems to be the best on road ride.
This is an unlimited and I would really appreciate feedback. Btw, the tires are goodyear silent armor 275/17
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Old 12-08-2012, 12:53 AM   #15
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Quote:
Originally Posted by SeeLee

I would like to drop my pressure lower than 35 but the tpm light in the dash lights up at 35 and below.
On my 2013 I have been trying different pressures to find a good on road ride since I am taking the family on a round trip from chicago to Florida to visit relatives. the dealer gave it to me with 40 and wow it was harsh. I dropped to 35 and it is better but 30 -32 seems to be the best on road ride.
This is an unlimited and I would really appreciate feedback. Btw, the tires are goodyear silent armor 245/75R17...
...
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Old 12-08-2012, 01:22 AM   #16
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I run the tire pressure on my 31X10.5's at 32psi. Seems to be a good place for mine mounted on 8" wide wheels...
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Old 12-08-2012, 08:38 AM   #17
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I did a test on high and low pressures for MPG, but it was not significant. I run 18 in the back, and 22 in the front based on the chalk test. It helps smooth the ride a little bit, but tires are not a part of the suspension and running low psi to smooth out the ride is not the ideal situation. Ideally the suspension would soak up the bumps, and you could run at higher pressures to keep the side walls stiffer in the corners.

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