tire pressure for 31s- chalk test no good

[92westshady]

Anyone have an further success with dialing pressure on the DuraTracs?

I am running the 245/75R16 on my Cherokee on 16x8 Moabs. I did the chalk test this morning at 28psi and still get about 3/4" of chalk remaining on the edges but then again my tires are only a few days old. I drive about 15 minutes on the highway on the way to work. I measured a 3psi change from 28 to 31 over the drive. The tires were very slightly warm to the touch upon arrival at the office. I might try to air down the tires and break-in the sidewalls a bit this evening.

If anyone has a pressure and tread wear story that tells the truth at this point I would love to hear it.

 

[cherokeeforbyer]

32psi for street, 10psi wheelin

 

[crash02]

32psi for street, 10psi wheelin

On an 8 or 10 inch wide rim?

 

[Tim_MN]

The point of the chalk test is to achieve the maximum possible uniform tread contact for your specific tire/rim/vehicle combination. You may or may not achieve 100% tread contact.

Normal tire inflation is about 26-32 psi for tires about 31x10.5, less for larger tires, more for smaller ones.

 

[92westshady]

The point of the chalk test is to achieve the maximum possible uniform tread contact for your specific tire/rim/vehicle combination. You may or may not achieve 100% tread contact.

Normal tire inflation is about 26-32 psi for tires about 31x10.5, less for larger tires, more for smaller ones.

The chalk comment makes sense but your suggested PSI range is interesting because I have always been told a few pounds of pressure can have significant effect on wear and fuel mileage. Sure everyone has their own preference for ride feel but I am looking for what is would be ideal for even wear and mileage. 26-32psi seems like a large range of pressures??

 

[Tim_MN]

... 26-32psi seems like a large range of pressures??

For a specific tire/rim/vehicle combination somewhere in that range should be good. Each Cherokee is different and so is its optimal tire pressure. Whatever tire pressure produces even tread wear is the ideal tire pressure.

 

[RCP Phx]

Part of your problem is the 8" rims,thats to small of a tire.I run 265/75/16 Duratracs but on 7" rims,no issues at all.

 

[92westshady]

Part of your problem is the 8" rims,thats to small of a tire.I run 265/75/16 Duratracs but on 7" rims,no issues at all.

This comment makes absolutely no sense. I a running Moab wheels on my Cherokee, if you are unfamiliar these are the wheels that came on the 2003-2006 Wrangler Rubicon and the factory tire size on the Rubicon is 245/75R16.

 

[flagdad]

If you continue to have trouble setting the air pressure, I would try setting them at something that 'seems' about right based on ride quality, handling, and the look of the tread contact. Then consider buying a tread depth gauge and measuring them now and then at your next oil change to see how they are wearing and make adjustments from there. Ideally, you'll be able to make adjustments based on uneven wear and get pretty close to your ideal pressure that way.

I am actually going through the same thing with my new Falken 31" tires at the moment. They are on 15x8 Ravine wheels. But, I don't trust what my tire gauge is telling me, so I verify with a different one when I get the chance.

American_zero I recently started running a 31” fallen mt and I’m trying to find the right pressure. Been running 28ish in the front and 26ish in the rear. If you find a sweet spot let me know what pressure you like.

 

[Black1990jeep]

So this morning my tires were at 24 psi. After driving to work they went up less than 2 psi, to just under 26. It was a bit colder outside than in the garage, so that probably reduced the pressure rise a little. Before driving home they were just over 26. It was quite a bit warmer out than when I drove in, maybe 30* or so. When I got home the tires were at 28 psi, a rise of 2 from driving and 4 from this morning.

So should I let some air out and try a lower pressure? It sounds low already but it isn't the 4 psi rise that's mentioned on gojeep's site.

Many tire pressure references refer to cold inflation pressure. The max pressure listed on tire side wall is a cold pressure. do not lower pressure cause of a hot reading. Cold pressure is what it is the values are for in near all references.

Now what is cold? My assumption is 70F, but I might well be wrong.

 

[Black1990jeep]

PS...

https://en.m.wikipedia.org/wiki/Cold_inflation_pressure

 

[lazyxj]

Each tire and rim combination has its own optimum pressures.
While I can't tell you what the best pressure is for tire life, I do suggest buying an inexpensive tire tread depth gauge and determining the correct pressure by checking the tread depth fairly often.
If the tire's center is wearing faster than the edges, lower the pressure, increase it if the edges are wearing quicker. With careful observation and adjustment, you can dial in the perfect pressure for road usage.
Some run at higher than needed pressure for the best gas mileage, which is fine if the cost of fuel per mile is cheaper than the tire cost per mile. My experience is the saving in gas mileage does not offset the increased tire wear costs.
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