Tire pressure qusetion

Chain Reaction

Chain Reaction

Active Member
Hey all,
I'm running 265/70 R17 Load range E ProComp A/T Sport tires and the sidewall says 80 PSI max (I know you don't run that much). Can I run 30 PSI or is that too low? I'm wanting to add them to the Ultimate True Tire Size database but also don't want to deflate them to an unsafe level for highway driving. Right now I'm running 45 PSI.
 
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Sgt_USMC

Sgt_USMC

Active Member
With load range E I would start at 28 like others said. With the thicker sidewalls of an E you will likely have to go a little lower to get a good chalk test result. Running at 45 that thing must feel like it has no suspension! I bet the handling isn’t great either. Does it tend to wonder a bit and constantly need correction?
 
Sgt_USMC

Sgt_USMC

Active Member
I’ve done the chalk test in the past and I saved this list as my go to bullet list for doing a chalk test. I do cover more of the tread than necessary with the chalk, and I do a couple revolutions of the tires each time. Also, if you normally carry a bunch of gear in the Jeep (tools, parts, compressor ect) do it with whatever gear you would have in the Jeep on a daily basis.


  1. Find a flat area around 25’ long
  2. Cover entire width of treat for 5-6”
  3. Drive in straight line for about 10-20’ (a couple of revolutions of the tire)
  4. Inspect chalk pattern remaining on tire
  5. Adjust air up for worn edges and untouched center, down for worn center and untouched edges
  6. Once the whole width is rubbed evenly the pressure is good
  7. Make a note of pressure for future reference
  8. ENJOY YOUR JEEP!
 
Chain Reaction

Chain Reaction

Active Member
Sgt_USMC said:
With load range E I would start at 28 like others said. With the thicker sidewalls of an E you will likely have to go a little lower to get a good chalk test result. Running at 45 that thing must feel like it has no suspension! I bet the handling isn’t great either. Does it tend to wonder a bit and
Click to expand...

Sgt_USMC said:
With load range E I would start at 28 like others said. With the thicker sidewalls of an E you will likely have to go a little lower to get a good chalk test result. Running at 45 that thing must feel like it has no suspension! I bet the handling isn’t great either. Does it tend to wonder a bit and constantly need correction?
Click to expand...
It does wonder quite a bit and I'm always correcting it and thought it was the tie rod ends. I will also say for the record, I didn't put these tires on. probably the same person who thought duct tape was a good way to insulate wires.
 
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