School me on E rated tire pressures

NFRs2000NYC

Caught the Bug
Hey guys, Im a little confused about this, so if anyone has a clue, by all means, tell me what Im missing.

Im looking to get 315/75/16 Duratracs for the new rig. I have seen many people talk about running them at 25psi, 28psi, 30, etc. Discount Tire told me that their minimum psi rating is 35psi. Now, Im not sure if they are telling me that for liability reasons or that is really the minimum they can be run at. I figured since they are E rated, they are extremely over-rated for the Jeep and can be run a lower psi.

Can anyone make me understand any of this?
 

OverlanderJK

Resident Smartass
You can run a tire at 1 PSI if you want. I'm pretty sure it's their policy to set it at 35 because they did with mine.
 

wayoflife

Administrator
Staff member
35 psi is what is recommend for tires of that size and at that psi, you will get an okay ride and best MPG. Problem is, Range E tires have really thick sidewalls and your ride quality will be on the harsh side at that psi and, depending on the width of your wheels, your tread will most likely not have full contact with the ground. Typically, people run 28 psi as it helps to solve both ride comfort and tread to ground contact on most common wheels.
 

NFRs2000NYC

Caught the Bug
35 psi is what is recommend for tires of that size and at that psi, you will get an okay ride and best MPG. Problem is, Range E tires have really thick sidewalls and your ride quality will be on the harsh side at that psi and, depending on the width of your wheels, your tread will most likely not have full contact with the ground. Typically, people run 28 psi as it helps to solve both ride comfort and tread to ground contact on most common wheels.

Thats what I figured. I guess my question was is it ok to run this tire at 28-30psi for local driving (I'd pump em up to 35-37 for a cross country drive for ideal MPG) and local highway driving without the tire exploding and sending me into through the pearly gates on fire. :D Sounds like I should be ok then.
 

Army_Vet

Banned
What I have learned.... the steel belts in your tires when run at extreme low pressures will flex more than designed. This will contribute to tire failure due to the snapping of the steel belts. Just an example to illustrate. A paper clip; if you bend it more than its designed to bend, it will weaken and break only after a few bends. However if you bend it slightly within its limits you can bend it back and forth forever.
Now I understand the steel belts are not made of the same metal that paper clips are made from; this was just an example to illustrate the point.

Tire companies employ guys in white lab coats to find the failure points of all these things; and this is what they have found.

Any body care to know why it is not recommended to plug a tire?
 

CaliCrusher

New member
35 psi is what is recommend for tires of that size and at that psi, you will get an okay ride and best MPG. Problem is, Range E tires have really thick sidewalls and your ride quality will be on the harsh side at that psi and, depending on the width of your wheels, your tread will most likely not have full contact with the ground. Typically, people run 28 psi as it helps to solve both ride comfort and tread to ground contact on most common wheels.

So what's the "cheat code" to turn off the low tire pressure light? Mine comes on around <37 psi.
 

wayoflife

Administrator
Staff member
Thats what I figured. I guess my question was is it ok to run this tire at 28-30psi for local driving (I'd pump em up to 35-37 for a cross country drive for ideal MPG) and local highway driving without the tire exploding and sending me into through the pearly gates on fire. :D Sounds like I should be ok then.

I personally run Range E Toyos and Nittos at 28 psi all the time and everywhere regardless of how far I need to go. It's never been a problem for me. For what it's worth, depending on the trip (something like JKX where you are on dirt and pavement on and off a lot), I've run them at 10-15 psi at highway speeds for hundreds of miles on end and without any problems. Once, I was unaware that one of my tires was completely flat and I wheeled all of Black Bear Pass like that and once, I drove over 40 miles like that on my way back from Fordyce to South Lake Tahoe in the middle of the night. Not the best thing in the world to do and not something I would recommend but, my point is that they held up just fine.
 

NFRs2000NYC

Caught the Bug
What I have learned.... the steel belts in your tires when run at extreme low pressures will flex more than designed. This will contribute to tire failure due to the snapping of the steel belts. Just an example to illustrate. A paper clip; if you bend it more than its designed to bend, it will weaken and break only after a few bends. However if you bend it slightly within its limits you can bend it back and forth forever.
Now I understand the steel belts are not made of the same metal that paper clips are made from; this was just an example to illustrate the point.

Tire companies employ guys in white lab coats to find the failure points of all these things; and this is what they have found.

Any body care to know why it is not recommended to plug a tire?

Ive been plugging tires for ages, including race tires. If they hold up on a racetrack, they sure as hell will hold up on a Jeep.
 

NFRs2000NYC

Caught the Bug
I personally run Range E Toyos and Nittos at 28 psi all the time and everywhere regardless of how far I need to go. It's never been a problem for me. For what it's worth, depending on the trip (something like JKX where you are on dirt and pavement on and off a lot), I've run them at 10-15 psi at highway speeds for hundreds of miles on end and without any problems. Once, I was unaware that one of my tires was completely flat and I wheeled all of Black Bear Pass like that and once, I drove over 40 miles like that on my way back from Fordyce to South Lake Tahoe in the middle of the night. Not the best thing in the world to do and not something I would recommend but, my point is that they held up just fine.

Thank you sir. Sounds like I dont have much to worry about. Many thanks!
 

Army_Vet

Banned
Ive been plugging tires for ages, including race tires. If they hold up on a racetrack, they sure as hell will hold up on a Jeep.

Yes so have I(except race cars).... I was not at all saying I wouldnt. Just asking if you(or anyone) were interested in knowing what the White lab coat guys found....
 

NFRs2000NYC

Caught the Bug
Yes so have I(except race cars).... I was not at all saying I wouldnt. Just asking if you(or anyone) were interested in knowing what the White lab coat guys found....

Oh sure, Ive never heard about plugging tires and side effects...other than the tire companies wanting to sell you a new tire everytime you run over a staple. If they have a legit reason, I'd be curious to hear it.
 

Army_Vet

Banned
Oh sure, Ive never heard about plugging tires and side effects...other than the tire companies wanting to sell you a new tire everytime you run over a staple. If they have a legit reason, I'd be curious to hear it.

Besides the one or few cords that can be broken from the puncture, and then reaming tool. The opening in the rubber will allow rust/corrosion to creep in and infect the rest of the cords.

With that being said, I think it should be know that it would take years for a tire to fail from this cause.

Tire companies do plug tires. but they do it properly; and seal the damaged area.

This does not mean manufactures will recommend plugging tires, but tire service companies will if state laws allow.
 

NFRs2000NYC

Caught the Bug
Besides the one or few cords that can be broken from the puncture, and then reaming tool. The opening in the rubber will allow rust/corrosion to creep in and infect the rest of the cords.

With that being said, I think it should be know that it would take years for a tire to fail from this cause.

Tire companies do plug tires. but they do it properly; and seal the damaged area.

This does not mean manufactures will recommend plugging tires, but tire service companies will if state laws allow.

Thats a plausible reason actually, but like you said, it would take years to rot away the steel...generally the tire will wear faster than that. I have my personal trick to plugging tires that has worked very well over the years. Ream the hole, stick plug onto tool and soak in rubber cement. Insert plug. Remove tool and add more rubber cement on top. (That stuff is done with the tire completely flat.) Then, I light the rubber cement on fire, and start inflating the tire. While its burning, the rubber melts and the air pressure from being pumped up pushes the plug tighter into the rubber and the slightly melted cement bonds it all together. I have never EVER had a single plug/tire failure with the above method. "100% of the time, it works everytime."
 

CaliCrusher

New member
You need a Superchips FlashCal, Flashpaq or AEV ProCal to turn it off.

I just read another reply you posted about the increased performance that the FlashCal offers automatic 3.8L JKs (but not manual trannys.) Does it offer the same upgraded performance for the automatic 3.6L Jeeps?
 

Atch

New member
I just read another reply you posted about the increased performance that the FlashCal offers automatic 3.8L JKs (but not manual trannys.) Does it offer the same upgraded performance for the automatic 3.6L Jeeps?

Last I heard they don't have one ready for the '12's+
 

Army_Vet

Banned
Thats a plausible reason actually, but like you said, it would take years to rot away the steel...generally the tire will wear faster than that. I have my personal trick to plugging tires that has worked very well over the years. Ream the hole, stick plug onto tool and soak in rubber cement. Insert plug. Remove tool and add more rubber cement on top. (That stuff is done with the tire completely flat.) Then, I light the rubber cement on fire, and start inflating the tire. While its burning, the rubber melts and the air pressure from being pumped up pushes the plug tighter into the rubber and the slightly melted cement bonds it all together. I have never EVER had a single plug/tire failure with the above method. "100% of the time, it works everytime."

I have seen it happen, but yes it will take years, just sharing some of my useless knowledge with others.....

I would not hesitate to run plugs. Funny story, the very first offroad adventure in my jeep on the dirt roads behind my house ended in a tire plug in the factory stockers...
 

NFRs2000NYC

Caught the Bug
Haha, I believe that it can happen. Makes perfect and logical sense. It's just that I rarely run a tire long enough to see it happen. Don't don't run tires till bald. I usually replace em after they got below 3/4. I'm OCD lol.
 
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