Hey how. I thought that a chalk test would give me some great insight to exactly how my tires were wearing... not so much. It basically ball parked things,.

Jen was giving me a hard time as I had her running around the parking lot, takeing pictures of chalk marks and my tires with funny colors of chalk on them. We now have a 16 pack of sidewalk chalk with all the colors, I'll be sure to bring it to Rocktoberfest for you Frank.

 

As with everything else, it is a tradeoff and a matter of preferences. IMO, the chalk test can result in a pressure value too low depending on the tire sidewall height and rim width and tread designed (square like MT ATZs vs rounded like KM2s). Personally, I go by handling, mpg and temperature (low psi will rapidly increase tire temp) and I find a happy medium for my taste.

ROAD:
On the road I've gone as high as 35-35psi because that's what installers pumped them up to. At this pressure (4dr)they feel you are ridding on motocross knobbies over metal plates. But I have to say you can feel a difference it tire friction even at the pump. At 30-31 the bumpy ride goes away and increased friction is moderate. When I dropped the pressure 27-29 the ride felt the best, but the friction was noticeable and the tires have a heavy feeling.

OFFROAD:

I've run as low as 10-12 psi for small stretches in sand, but normally don't like to go below 15 psi. With narrower rims (7.5") you can get away with lower pressure. Just feel the tire temperature afterward. Heat is one of tires worst enemies.

BTW, IMO the KM2's are also quietest at 30-31 lbs, although it's hard to tell because there are so many noise makers on the Jeep, but the KM2 are very quiet for their void ratio.

 

Just messin' with you! we'll your lucky it's gonna be a non-kids weekend for us otherwise your chalk would be gone!

Lookin' forward to those adictive rice krispy crack like treats Jen makes and having a with you. TTYL

 

I use mine as a daily driver and want gas mileage and wear to be maximum. I therefore run 40 psi on highway roads and air down to 15 psi on the trails. I have KM2 35" on 17" rims.

 

Have you driven them in rain at this pressure?

If find my 35s feel a bit dicey above 35 psi in the wet.

 

Man, hgh pressures. I run 24 for comfort, sometimes up to 26 depending on my mood.

I run 12 psi off road and they perform great with no bead issues on the rocks.

Above 28 and the thing gets touchy, and is rougher than a wild bore in heat.

I should run 26 for wear, but so far the wear is still good.

You guys running 30psi..,.arent you getting killed over bumps?

 

I have the Teraflex full suspension and the higher psi does not really kill me over the bumps. Granted, the really bad roads, I definately feel but the Arizona roads are pretty good.

In regards to rain, I have not noticed any challenges. Granted we only get heavy rain in July during Monsoon season. I would have to say no problems.