Is 23 psi too low?

[jlandry287]

So I'm running 37x17 Nitto ridge grapplers and normally running 26 - 28 psi. It rides a little rough and wanders, but it's a lifted Jeep on 37s.

This morning when I was on the way to work I looked at tire pressures and they were down to 23psi. Surprisingly it rode smooth as butter.

I know each tire is different and it depends on a lot of variables, but those who have 37x17 Ridge grapplers what PSI do you run?

Also, is there any negative to running 23 psi long term? the tire seems to be making good contact with the pavement and doesn't appear to be flattening.

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[ParadigmDawg]

I run 30 on RG 37x12.5x18 in my TRX which is a lot heavier and never had issues. Anything over 33 and the truck is all over the place.

 

[jlandry287]

I run 30 on RG 37x12.5x18 in my TRX which is a lot heavier and never had issues. Anything over 33 and the truck is all over the place.

I'm in the diesel so it's heavier than most jeeps, but I don't think it's as heavy as a TRX

 

[Cunky]

I'm not sure what "too low" is considering the size and extra weight of the diesel. There can be significant safety concerns pertaining to the sidewall integrity if the psi is too low and you're traveling at on-road speeds. My advice is to contact the tire manufacturer with this question. Sidewall blowouts are both pricey and extremely dangerous @ speed.

 

[rcadden]

Have you done a chalk test?

 

[jellis4148]

26 psi cold is what I run. Jeep rides and drives good at that pressure. The shop put 30 in them one time, and I knew instantly they had. Drove like crap. Anyway, 26 psi seems to give me the best wear, ride, and drivability. Put in what you're happy with.

 

[Aonar]

So I'm running 37x17 Nitto ridge grapplers and normally running 26 - 28 psi. It rides a little rough and wanders, but it's a lifted Jeep on 37s.

This morning when I was on the way to work I looked at tire pressures and they were down to 23psi. Surprisingly it rode smooth as butter.

I know each tire is different and it depends on a lot of variables, but those who have 37x17 Ridge grapplers what PSI do you run?

Also, is there any negative to running 23 psi long term? the tire seems to be making good contact with the pavement and doesn't appear to be flattening.

I know you just ran them at this PSI once so far, but I would chalk test them. I am set at 27-28 cold and 30 hot on D range pizza cutters. I rotate religiously, mind you.

This should give you some visual proof on your contact patch.

 

[GATORB8]

You should be fine load wise with either the 12.50 Ds or 13.50 Es at that pressure.

Remaining concerns would be cornering stability, additional load on steering components due to the increased friction at the contact patch, and if you are still wearing evenly and not light in the center of the tire.

 

[kah.mun.rah]

Also, is there any negative to running 23 psi long term? the tire seems to be making good contact with the pavement and doesn't appear to be flattening.

Lower PSI can generate more heat. Increased heat can degrade the rubber and cause cracking. If you are getting even contact via a chalk test and don't notice any deflection, go with what you are comfortable with.

 

[6.2Blazer]

As shown in an above reply, the load inflation chart shows that each tire can support 2,150 lbs. @ 25 psi. Based on that the tires could support just under 2,000 lbs. @ 23 psi. Times 4 tires and that is almost 8,000 lbs. total weight which is well above the weight of the Jeep.
The only sidewall issues because of tire pressure is if you run too low of air pressure for the total weight AND run at higher speeds (i.e. highway) for prolonged periods of time. Too low of pressure allows the tires to flex excessively every revolution and thus causes heat build-up and fatigues them, than the sidewalls will fail. Think of a tire that is partially flat with an obvious large bulge on it. As you drive that bulge is constantly moving which means it is flexing the sidewall. First it will get really hot and decrease the strength of the tire. Now think of a paper clip....if you bend it back and forth several times it doesn't break, but if you keep bending it back and forth it will eventually fail. That is what is going on with a partially flat tire. To be clear, when I say "partially flat" that means the tire does not have enough air pressure to support the weight.

 

[Chance_P]

I have stt pros (E rates 37s) that I run 25 psi daily with no issues and great wear

 

[c20040215]

I have the same tires and size I run 25-26 psi cold at 75ish F ambient temperature. Works great for me. Even wear, tracks straight, and rides nice.

 

[XtremeRetard]

I hate low pressure on the road.
High pressures like 40psi feel much lighter on the road, performance is better, mpg etc.
Low pressures, it feels dead, sure it might just plow on with less twitching, but yuk.

Off road Im down around 10psi. But on road 40 works best for me. Chalk test sucks. Its meaningless without context. You want less contact on the road for better economy etc. Which explains why dealers set to around 40+ psi when you collect your new jeep..

Just IMO.

 

[KCSgtMaj]

You should be fine load wise with either the 12.50 Ds or 13.50 Es at that pressure.

Remaining concerns would be cornering stability, additional load on steering components due to the increased friction at the contact patch, and if you are still wearing evenly and not light in the center of the tire.

Ditto. Tire pressure inflation is set based on the weight each axle is carrying. Look for the mfg’s inflation table for the specific tire you have.

 

[iddpaul]

I've been running 37x12.5x17 Nitto Ridge Grapplers for several years, have heavy beadlocks, 3.5 inch lift, extra weight and normally set the pressure at 26 psi cold (road conditions dependent). I've spent some time changing pressures to get the best "feel", love how it handles at 24 psi cold (IMO this pressure doesn't show too much sidewall deflection and the chalk test shows contact evenly on the tread), but hate how it handles at 32 and above psi (which the dealer will try to set). Apart from looking at actual wear on the tires (and reading charts, etc.), I think the chalk test helps to assess pavement contact (and I've done this multiple times). I also do a regular 5 tire rotation and dependent upon summer/winter will fluctuate between 24-26 psi cold. (Yes I do run at 24 psi on road and air down for off-road). Again IMO, you should maybe do some tests to see what makes the most sense and gives you the best control, but obviously be cautious because if you go too low for everyday driving then you run the risk of "under inflation" and the problems that come with that condition.

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