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Discussion Starter #1
i am running coopers stt---245/75/16 load range E, 10 ply, tires on my truck. it calls for 80 psi!!! what is the lowest psi i should run while just using it on the hwy and what should i run while in the mud/sand?
 

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Just duct tape it!
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i think thats max load though right? You shouldnt be anywhere near that. If you are completely unsure (i also dont know what those should be at) Do the chalk test to see what the most even wear is. Others will probably tell you what they have theirs set at if them have them.
 

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Discussion Starter #3
yes 80 is max and i am currently running them @ 40 but i want to go lower for a more smoothier ride. just wondering how low i could run them. thanks for the input
 

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05 Tacoma DC 4x4 TRD
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Just watch the sidewall and make sure the tread pattern touches the ground evenly, and doesn't cup. Load range E is generally used for heavy duty full size trucks.
 

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Discussion Starter #6
i do a lot of hunting around south texas. we have a lot of mesquite thorns, cactus and other heavy thorned types of brush.:thumbdown i have a lot rough roads and heavy brushed roads that i have to travel throughout the months of august to jan. i used to get a lot of flats with 8 ply and have had zero with these 10 ply.:clap:
 

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06 DC 4x4 TRD Sport Tow
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I've heard two rules as to air pressure...

1. Follow vehicle manufacturer recommendation as stated on b-pillar.

or

2. Max PSI - 10 % rule. Which in this case would be 80PSI - 8 = 72PSI which is obsurd.

but

Rule 1 recommendation needs tweaking since putting on some new winter rims running BFG A/T 245/75/16 the recommendation just feels wrong and appears to be evident as I measure tread depth across the tire regularly looking for the optimum PSI.

If i've learned anything its to use a digital air pressure gauge and throw away the stick gauges.

I'm still pondering what the best PSI fill should be...anyone know?
 

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2005 trd tacoma
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hi i work at discount tire and ive been in the tire buisness for quite a while. for highway and in town use 35 to 40 psi is good and for offroading like mud and sand you can safely go as low as 15 psi, but make sure you fill them up before going on the road again.
 

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My Other Truck
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SOTXYOTA, that's the first valid reason I have heard of for running LR-E tires on a Tacoma. As noted, 80 psi is the max for the tire when loaded to the maximum weight capacity -- which you will never come close to. Start by simply running the pressure your owner's manual -- or door sticker -- calls for. Keep a close eye on your wear pattern and adjust as necessary.
 

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Not completely applicable but my F-350 ran "E" tires. They were happiest at 55psi. 40psi was smoother but I started getting uneven tire wear. As stated above a chalk test or watch the sidewall and contact patch.
 

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SOTXYOTA said:
i am running coopers stt---245/75/16 load range E, 10 ply, tires on my truck. it calls for 80 psi!!! what is the lowest psi i should run while just using it on the hwy and what should i run while in the mud/sand?
I've played with inflation pressures quite a bit with my Toyo MT's, and settled on 36 psi all the way around. I've found that to be the best compromise for ride quality and MPG. Oddly enough, that's what Les Schwab told me to run when I left their shop anyway.

When hunting, I drop the psi to 18 lbs in order to save my dental work and kidneys on the NFS roads. When we wheel in the snow, I'll nominally run 9 lbs and sometimes go as low as 7 (but no lower) depending on the nature of the snow.
 

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06 DC 4x4 TRD Sport Tow
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SOTXYOTA said:
i am running coopers stt---245/75/16 load range E, 10 ply, tires on my truck. it calls for 80 psi!!! what is the lowest psi i should run while just using it on the hwy and what should i run while in the mud/sand?
Here's one way to figure...If I recall correctly, your tires are rated for 3000lb's each. That's 12,000 pounds of load range capability. Substract your gross vehicle weight...for simple math sake...a 4x4 DC LB is approximately 6000 pounds. Assuming you have a 50/50 weight distribution over the 4 tires that's 50% load. That means with a maximum 80PSI cold rating you could figure running your tires with 40PSI (50% of 80PSI).

You can run your tires pretty low, say 18 to 20PSI...some even lower but I'd experiment since I wouldn't want to damage my tires or rims. Besides, you'll also sacrifice some ground clearance going low on PSI. Its trial and error as every tire reacts differently to offroad conditions based on tread and material design. I got stuck one time and lowered the pressure from the tire spinning and that's all it took to grab differently...have to be careful you don't do any damage though and try not to spin the wheel.
 

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I ran Es on a F250 diesel. I think I used about 60.

I have run many vehicles in the sand. I stand by the rule of thumb to drop the distance from the bottom of the rim in half. I've seen a lot of beads break below 10 lbs. I would not do that. The other thing about using the 1/2 rule is that it automatically accounts for different loads, etc. No one air pressure number is always right.
 
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