30 Inch tire pressure

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ApproachMedium
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30 Inch tire pressure

Post by ApproachMedium »

What tire pressure should I be running with 30x9.5s on my crew? I have 15 inch ZR5 wheels and the V8 swap so theres a little more weight on the front end. The sidewall of the tire says 50 PSI but the truck door says 32 i believe. My friend who put the tires on for me set them at 40PSi and they look like they are a little low in the front as the truck sits. Im also not getting so great of MPG which is why I asked.

Speedo has been checked at speeds from 40-80mph and it is on the money with my phones GPS system.
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roadrunner
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Re: 30 Inch tire pressure

Post by roadrunner »

My sidewalls (BFG 235x75x15 AT tires that measure 29.5x9 I believe) also say 50psi and it has been my experience that running anything much lower than that hurts my fuel economy and my tires are wearing evenly at that pressure as well. Others will argue differently but that is my personal experience.
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killian96ss
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Re: 30 Inch tire pressure

Post by killian96ss »

32 psi cold. The 50 psi mark on the tire is the max pressure allowed for that tire, not the recommended pressure.

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Re: 30 Inch tire pressure

Post by ApproachMedium »

But it doesnt say max tire pressure on the side of these tires? It says load support at 50PSI in one place and then somewhere else it says 50PSI.
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Re: 30 Inch tire pressure

Post by ApproachMedium »

CORRECTION, i take it back. I just looked it up online on the General tire site. They said for the 30x9.5 Grabber AT2 it is 50PSI MAX. The tire itself does not say max for some reason..
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Re: 30 Inch tire pressure

Post by AVTekk »

32psi is too low, that is for a standard tire rated at 35psi max. Its up to you what you want to set them at, usually I put them 40-44psi when theyre rated for 50, but mostly for comfort. My 31s are D or E rated and i have to run them around 20spi or the truck rides like a brick.
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Re: 30 Inch tire pressure

Post by HenryJ »

Tire pressures and airing down for offroad
Find and empty parking lot.

Inflate your tires to the max pressure listed on the sidewall.

Mark the tires accross the tread with a piece of chalk or crayon whatever really.

Drive straight forward several feet, be sure not to turn at all.

Look at the mark across the tread and see which part of mark has worn off.

If the mark has worn off at the center but not at the edges you have too much pressure (duh i already told you max pressure would be too much). Drop the pressure and repeat steps 2-5 until the desired pattern is achived. Be careful too low of a pressure will rub the mark so allways start with too much and work your way down.

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Re: 30 Inch tire pressure

Post by roadrunner »

The 50psi marking on the side of the tires indicates max COLD inflation pressure.
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Re: 30 Inch tire pressure

Post by ApproachMedium »

Thanks for the info guys. I will try the chalk method. I brought the front tires up to 42PSi today and already I can feel a difference. I left the rears alone as they do look ok.

I do understand now fully that the 50 PSi is the MAX Cold inflation rating. I will avoid that at all costs.
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