Chalk Test Results

[CarbonSteel]

I am assuming that I need to reduce the pressure a bit more to have full contact or is this close enough?

Currently at 33PSI.

@blnewt

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[Chocolate Thunder]

The outermost edges of that tread are not intended to touch the ground unless you’re cornering.

 

[blnewt]

I forgot if those were E-rated, if so you may want to go down to 30, that seems to be where my E-rated Pats liked to be, and you'll get a bit more contact patch, just a bit I heard those Kanatis were similar to the Patagonias as far as being a bit curved vs. a flatter contact patch on most other brands.

 

[WranglerMan]

My KO2 35’s chalked out at 30#, the DT Tire Rep said they are wearing really well, not sure how many more miles I can get from them but currently have about 30k on them and they are 1/2 gone according to there specs and mine are “C” rated

@Chocolate Thunder i did not know that the outer lugs could show chalk, I would have thought the pressure needs to be lowered.

 

[CarbonSteel]

I forgot if those were E-rated, if so you may want to go down to 30, that seems to be where my E-rated Pats liked to be, and you'll get a bit more contact patch, just a bit I heard those Kanatis were similar to the Patagonias as far as being a bit curved vs. a flatter contact patch on most other brands.

They are load range E. I will lower to 30 and retest. Thanks for the tip.

 

[limeade]

The outermost edges of that tread are not intended to touch the ground unless you’re cornering.

@Chocolate Thunder i did not know that the outer lugs could show chalk, I would have thought the pressure needs to be lowered.

If the tire is meant to run on the center tread blocks (crown), such as the Milestar Patagonia MT's, then the chalk test is irrelevant and you need to run the pressure on the door or recommended by the tire manufacturer. I'm not sure what other brand/model tires are made to run on the crown other than the Pat MT's. The Pats are designed to run on the crown since the centers are an all terrain tread and the outers are mud terrain. They also do this to keep the noise level down.

For other tires meant to run on the full contact patch (BFG AT's and MT's, Cooper STT Pros, Nitto TG's and RG's, etc.) then the chalk test is an excellent way to determine the proper pressure you should run. This is especially true if you've added a lot of weight (skids, winch, etc.), have a tire load rating higher than stock, etc. You definitely want a full contact patch for the vast majority of tires as this provides the best traction and grip, whether that's high speed cornering or slow speed rock crawling.

So @CarbonSteel , I would lower the pressure until the chalk is worn off evenly across the contact patch, unless of course those tires are meant to run on the crown., but don't go too low. A tire with too little air pressure will get hotter than a similar tire with the correct pressure (or even too high pressure). This excess heat will lead to increased wear and under certain conditions, tire damage (tread separation, sidewall blowouts, etc.). Remember the Uniroyal tire fiasco on the Ford Explorers about 20 yrs ago? The tires weren't defective, it was the low pressure as spec'd by Ford which lead to the tire failures.

I'm unfamiliar with the Katai's, but they look similar to Duractracs, which are a flat contact patch tire. Plus, your tires have siping on the center and outer tread blocks, so that right there tells me they would be a flat contact patch tire.

 

[CarbonSteel]

I'm unfamiliar with the Katai's, but they look similar to Duractracs, which are a flat contact patch tire. Plus, your tires have siping on the center and outer tread blocks, so that right there tells me they would be a flat contact patch tire.

The Kanati's are very Goodyear Duratrac-esque and so I suspect you are quite right in your assessment and as such are full contact tires. I am mindful of going too low on pressure because I have seen tires get very hot when under inflated. I will not go below 30PSI in the interest of safety despite the contact area.

 

[WranglerMan]

When I first got my 35” KO2’s I ran the pressure at 35# and the ride was very bouncy so I got some chalk and went down 1# at a time and ended up in the 29-30# cold range and once warm they normally run 32-33# which is in the 10% range and from my research that’s about right, I do go down to about 25# on the sand and air up before I hit the road

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