Been adjusting PSI on JLR

[Old Jeeper]

Been tinkering with PSI on my JLR. What I have finalized is: 33.5. Front, 32.5 Rear Street only.

Tires: 35 x 12:50 X 17 Goodyear Duratrac

Wheels: Fuel 17 x 9.5

Jeep is OEM stock except for the tires and wheels


The pics are showing the contact patch which I used to arrive at the PSI required. Laterally you want to go edge to edge but not over the edge of the shoulders. This optimizes the mpg, braking, and coefficient of traction.

NOTE: This only applies to my JLR, these tires and these wheels. Your psi with the same tires may arrive as a different number albeit close.

The was captured in the flat dirt (dust) parking area. The dust had not been watered down (they were watering down the parking area but had not got to where I was driving thru.

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[Shibadog]

Sounds about right. I run 32 -a lot better ride and handling that the 40 psi it came with?

 

[Deleted User 38384]

Been tinkering with PSI on my JLR. What I have finalized is: 33.5. Front, 32.5 Rear Street only.

Tires: 35 x 12:50 X 17 Goodyear Duratrac

Wheels: Fuel 17 x 9.5

Jeep is OEM stock except for the tires and wheels


The pics are showing the contact patch which I used to arrive at the PSI required. Laterally you want to go edge to edge but not over the edge of the shoulders. This optimizes the mpg, braking, and coefficient of traction.

NOTE: This only applies to my JLR, these tires and these wheels. Your psi with the same tires may arrive as a different number albeit close.

The was captured in the flat dirt (dust) parking area. The dust had not been watered down (they were watering down the parking area but had not got to where I was driving thru.

Oh man, great choice and tires. That's the ones I'll be buying in the not so distant future. I don't think a lot of people realize, you'll get 60,000 mi out of Duratrac's if you treat them well. It's the number one rated pickup truck tire, popular amongst all the construction workers I know!

I was reading another thread on here a couple weeks ago and decided to drop my PSI from 38 on the OEM Destination M/T's (I liked the stiffer ride, and I was getting about a mile per gallon more at this PSI), to 32 psi all around.

The biggest thing I noticed is I used to hit the bump stop on every little bump in the front because I don't run with the sway bars attached. The thread I was reading recommended lowering the PSI and you hit the bump stops less. After lowering it to 32 psi, honestly I can go through some pretty decent sized bumps at speed and not bottom out. It took me a minute to get used to the lower PSI though. Even only dropping 6 psi I could feel the difference on the road. Much more cushy, but also felt a little more movement in the tire side to side. It might have just been my mind, I don't really notice it now, but I also beat up my tires pretty well on daily use.

The Carfax app the dealership signed me up for, seems to think I'll still have 2 years on my tires for tread life. I'm down to 7/32nds all around from 18/32nds when I bought it a little less than a year and a half ago. Only have just under 19,000 mi on these tires right now. I'll be lucky if I get to 30,000.

Yep, I'm the guy who does burnouts at the red light on a rainy day! Or is drifting around those gravel roads on a dry day! Or will spin my rears climbing up something I shouldn't be climbing up!

 

[Luxy60]

Sounds about right. I run 32 -a lot better ride and handling that the 40 psi it came with?

Doesn't the low tire pressure idiot light illuminate at these pressures?
Also considering Duratec's when I replace my stock Firestones.

 

[JCarlos]

Oh man, great choice and tires. That's the ones I'll be buying in the not so distant future. I don't think a lot of people realize, you'll get 60,000 mi out of Duratrac's if you treat them well. It's the number one rated pickup truck tire, popular amongst all the construction workers I know!

I was reading another thread on here a couple weeks ago and decided to drop my PSI from 38 on the OEM Destination M/T's (I liked the stiffer ride, and I was getting about a mile per gallon more at this PSI), to 32 psi all around.

The biggest thing I noticed is I used to hit the bump stop on every little bump in the front because I don't run with the sway bars attached. The thread I was reading recommended lowering the PSI and you hit the bump stops less. After lowering it to 32 psi, honestly I can go through some pretty decent sized bumps at speed and not bottom out. It took me a minute to get used to the lower PSI though. Even only dropping 6 psi I could feel the difference on the road. Much more cushy, but also felt a little more movement in the tire side to side. It might have just been my mind, I don't really notice it now, but I also beat up my tires pretty well on daily use.

The Carfax app the dealership signed me up for, seems to think I'll still have 2 years on my tires for tread life. I'm down to 7/32nds all around from 18/32nds when I bought it a little less than a year and a half ago. Only have just under 19,000 mi on these tires right now. I'll be lucky if I get to 30,000.

Yep, I'm the guy who does burnouts at the red light on a rainy day! Or is drifting around those gravel roads on a dry day! Or will spin my rears climbing up something I shouldn't be climbing up!

Greg if I didn’t know better I’d think I wrote this, same year Willys same miles and yeah tires seem to not be lasting for shit. Picked it up from the dealership after the oil change and they had the psi at 40, drove straight home and dropped them back to 34

 

[Deleted User 38384]

Doesn't the low tire pressure idiot light illuminate at these pressures?
Also considering Duratec's when I replace my stock Firestones.

I don't know what the actual idiot light comes on at, but Friday morning it was 28° here in Anna, Texas and my PSI was at 31 in the rear and 32 in the front. No tire pressure light. In early January we had a couple of extremely cold days in a row, like 12-13° days. My tire pressure got down to 24 psi. And it was lit up at that point. If I had to guess, it probably goes on around mid to high 20s. 26 to 28 is my guess.

 

[jellis4148]

I run 28 psi cold. Anything over that and the tires don't wear correctly. I would think 33 and 32, like your at would cause the tires to cup real bad. Did you do a chalk test or just basing the pressure off of ride quality?

 

[Fast-n-Furious]

I run 28 psi cold. Anything over that and the tires don't wear correctly. I would think 33 and 32, like your at would cause the tires to cup real bad. Did you do a chalk test or just basing the pressure off of ride quality?

I wanted to run 28-30 psi but can’t stand the low tire pressure alert. Is there a simple solution without buying a Tazer to set the threshold to a lower psi?

 

[jellis4148]

I wanted to run 28-30 psi but can’t stand the low tire pressure alert. Is there a simple solution without buying a Tazer to set the threshold to a lower psi?

Unfortunately no. I just ignore the light. I’d rather have it than ruin tires.

 

[Fast-n-Furious]

Unfortunately no. I just ignore the light. I’d rather have it than ruin tires.

I’ll probably go the same route. Have to compromise.

 

[Ratbert]

This optimizes the mpg, braking, and coefficient of traction.

I'm fairly sure that MPG would increase at higher pressures. At, of course, the cost of diminishing other desirable characteristics.

 

[dragoneggs]

I’m finding I like 32psi with my new 315/70-17 KO2s. Stock JLR. Yeah I can get better mileage pumping them up to 36-38psi but hate the feel.

 

[Rubi6mt]

I'm at 30.5psi all round cold on 315/70/17s.

At my jeep weight this psi provides even chalk test.

Have a procal set to 28psi so no low tire pressure warning.

If I go 65mph, I still get about 19-20mpg babying it in 6th

 

[BRuby]

Tracked wear depth with gauge over many years. Best with OEM KO2s is 28 for even wear across the tread. Whatever brand or size do the chalk - but track with gauge each and every rotation. Include your spare for 5 tire - minimizing dry rot.

 

[Ratbert]

Be aware that the weight of your Jeep impacts all of this. That makes boilerplate suggestions about tire pressure somewhat challenging.

Supposedly you can measure the size of your tire's contact patch (width times length in inches), multiply that by four (4 tires), and multiply that by your average tire pressure in PSI. That should, according to the math / science, give a decent estimate of the weight of your vehicle in pounds.

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