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Discussion Starter · #1 ·
Since there are always questions about what tire sizes, tire pressure, tpms settings with programmers, I thought this might prove interesting so here is the idea.

List your Jeep's
year,
model, (JK, JKU, JKUR, JKUS)
Tire brand (GY Duratrac, Nitto Grappler etc.)
Tire size, class and weight if known,
Wheel data (aluminum or steel, size, offset, make and model
Any weight related mods (bumpers, armor, winch) with weights if known

And of course, pressure where the front and/or rear tires passed the chalk test.

Ok so I have nothing better to do tonight so lets see if this goes anywhere.
 

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Discussion Starter · #2 ·
I'll start

The parameters are on my signature
the additional data is that the Duratracs are E rated, 34 x 12 and about 30 lbs heavier than the stock 32 x 10 18" wheels
4.5" backspacing on the aluminum V-tec Warlords
The front bumper is about 130 lbs
The winch was about 80 with the fairlead and steel cable
The spotlights are about 5 lbs
The rear bumper and carrier weighed in at around 100 lbs
I keep the spare tire on the carrier
No other armor at the moment.

Passed the chalk test at 30 psi so I set the flashcal to 26 psi
 

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The chalk test is a great way to gauge pressures but there's going to be some inconsistencies if
- running a 12.5 tire (most common) on a 7 or even 8" wheel. The tires tend to balloon and less psi is needed for full contact.
- worn tires from improper alignment ie feathering /cupping.

I run E rated 315/75/16's. Light weight 2 door w/ only a front stubby 100 lb bumper.
24 psi for full contact, but I run 26 psi
 

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I AM THERE4 I JEEP
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12,295 Posts
Oh sure, just shoot down his thread right from the start lol.

What jeeper said is true though. :D
 

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Running 35" BFG KM2's - with the hard top on, the winch, security box and all my gear, 28psi was the right number. MPG is 14.5. I rotate all 5 after every oil change myself. May be overkill on the rotation, but I want these things to last as long as I can. Wear has been exceptional btw with close to 40K on them now.
 

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Discussion Starter · #6 ·
The chalk test is a great way to gauge pressures but there's going to be some inconsistencies if
- running a 12.5 tire (most common) on a 7 or even 8" wheel. The tires tend to balloon and less psi is needed for full contact.
- worn tires from improper alignment ie feathering /cupping.

I run E rated 315/75/16's. Light weight 2 door w/ only a front stubby 100 lb bumper.
24 psi for full contact, but I run 26 psi
Makes sense for a lighter JK without much extra weight on the front or rear bumpers and the tall wide tires on smaller rims.

Im thinking this thread would apply to a well aligned rig with newer rubber

Oh well. Doesn't look like it's going anywhere anyway.
 

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08 jkur 35" GY mtr/k running at 25 psi cold (almost full contact) but dislike the fact that when turning the steering wheel gets jumping as most of the contact goes from the whole surface to 2/3 of the surface and mostly the outer (lugg) side. Im in a pickle either run higher psi and wear out the center faster or just deal with the extra tire lugg effect
Edit: 35x12.5/17 stock wheels , hard top and front poison spyder brawler lite with skid
 

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07 JKU - Soft top Stock bumpers Stock wheels
LT285/75R17 Nitto Terra Grapplers
Chalk test at 27PSI, usually run at 28-30.
 

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Anyone do a chalk test with stock size DuraTracs on stock 17" wheels?

I've been running them at 33 PSI but didn't chalk test them yet.
 

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08 JKU 35x12.5x17 Pitbull Rockers 26psi

09 JK 35x12.5x17 Pitbull Rockers 24psi

07 JK 33x12.5x16 BFG A/T KO 30psi

13 Power Wagon 35x12.5x17 Pitbull Rockers 40psi
 

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07 JKU 37x12.5x17 MT/R wKevlar on 17x10 rims

Chalk test last night at 33 showed a quarter inch of intermittent chalk on the outer lugs. Going to try 32 this afternoon.

Lunatic Fridge
 

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2012
2 door rubi
Duratracs
315 75/16
level 8 zx
front LOD armorlite w/ synthetic line winch, hardtop, full size spare, (stock rear bumper)
26psi
 
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