Psi ?
rtball
Joined: Feb 2019
Posts: 667
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From: Central Florida & East Texas
He told us what tires they are. You could look them up.
LT275/70/18 GoodYear Wrangler Adventure
https://www.tirerack.com/tires/tires...tnum=77SR8WATA
Load Range: E. Max PSI: 80
That max is clearly not relevant to a half ton, of course.
LT275/70/18 GoodYear Wrangler Adventure
https://www.tirerack.com/tires/tires...tnum=77SR8WATA
Load Range: E. Max PSI: 80
That max is clearly not relevant to a half ton, of course.
Is he going to get heavier duty springs, HD axle, and what else. I think someone sold him a bill of goods to convince him these tires were right for him. He still has a max weight rating for his truck to deal with, which BTW will be less now since the tires weigh more.
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Joined: Aug 2018
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These tires are way beyond what would ever be required on a half ton truck, as noted above. Load range E. The ride comfort will be ridiculous. We will see a new thread about uncomfortable ride, help!
Is he going to get heavier duty springs, HD axle, and what else. I think someone sold him a bill of goods to convince him these tires were right for him. He still has a max weight rating for his truck to deal with, which BTW will be less now since the tires weigh more.
Is he going to get heavier duty springs, HD axle, and what else. I think someone sold him a bill of goods to convince him these tires were right for him. He still has a max weight rating for his truck to deal with, which BTW will be less now since the tires weigh more.
Yeah we'd see a thread about uncomfortable ride if he kept them at the ludicrous 75 PSI they were aired up to lol
Last edited by blkZ28spt; Oct 18, 2019 at 09:22 AM.
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According to the specs of this tire, the Max inflation is 80psi. They are safe to inflate to that pressure but, you only need to increase the tire pressure with this type of tire when you are carrying a heavy load such as a camper. Under normal load, 45psi should be good enough. When I worked, our trucks were marked with a max/min tire pressure and with similar tires as these they were marked at 45/80psi. The should operate and wear pretty good a 45psi under normal conditions.
Thread Starter
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Joined: Mar 2016
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What I was asking in my original post was about an everyday unloaded pressure for good tire wear because I too was surprised the shop set them to 75.
My truck came with these same tires just a size smaller........LT275/65/18 which I kept at 36 PSI as per the door jamb sticker.
That tire was part of the FX4 package I believe.
I installed a 1.5 inch level kit and that is what drove me to the taller tire.
I do use my truck as a truck, I tow and hall a decent amount, during those times I will up the pressure to accommodate the load and keep the side wall from heating up.
Thanks to you guys that offered ways for me to achieve my answer!
My truck came with these same tires just a size smaller........LT275/65/18 which I kept at 36 PSI as per the door jamb sticker.
That tire was part of the FX4 package I believe.
I installed a 1.5 inch level kit and that is what drove me to the taller tire.
I do use my truck as a truck, I tow and hall a decent amount, during those times I will up the pressure to accommodate the load and keep the side wall from heating up.
Thanks to you guys that offered ways for me to achieve my answer!
Senior Member
Joined: Jan 2013
Posts: 305
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From: SE PA
I wet the tires, then roll on driveway to get print of full tread width . Lower each tire PSI till full print ( you will see outer edges touch ) reached . Each tire and wheel width combination will have unique numbers on each truck . HTH
Senior Member
Joined: Jan 2018
Posts: 276
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From: Midwest
I would think the psi for tires would be pretty similar regardless of maker. My Michelin Defender LTX M/S, 275/65/18 123R's are rated at 80 psi max. Per Michelins Tire Pressure Chart, they recommend 35 psi @ 1910 lbs. per tire, we run them 36-37. Our curb wt. is about 5683, divided by the 4 tires that comes to 1421 lbs. per tire, well under the max of 1910 @ 35 psi. Naturally as the weight of the truck and towing increases so will the psi. I think this logic is sound.
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Joined: Jan 2019
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So here is one of the ways you can figure out how much air to run in your tires.
1. Weigh your truck; front tires on the scale then rear tires on the scale.
2. Read the max psi @ what weight on the side of the tire. Something like 3250lbs @ 60psi, (just an example).
3. Divide the weight by the pressure, in this case it would be 3250/60=54.1 So, every pound of air pressure holds 54.1 pounds of truck.
4. Take your trucks front weight and divide it by 54.1. IE: trucks weighs 3500 lbs on the front tires, so... 3500/54.1=64.7 so that would be 64.7 psi. Divide that by 2, since you have 2 front tires, 33 psi.
5. Your tires need AT LEAST 33psi to hold up the front weight of your truck. Take this number and add a few pounds for security reasons and see how your tires wear.
6. Do the same for the rear. Yes, you will run a lot less in the rear tires when the truck is unloaded.
You can run more air in them if you like, but DO NOT run less than this number that you come up with. I do this with all of my trucks and my tire guy is always amazed at the mileage I get out of my tires.
Good luck!
David
1. Weigh your truck; front tires on the scale then rear tires on the scale.
2. Read the max psi @ what weight on the side of the tire. Something like 3250lbs @ 60psi, (just an example).
3. Divide the weight by the pressure, in this case it would be 3250/60=54.1 So, every pound of air pressure holds 54.1 pounds of truck.
4. Take your trucks front weight and divide it by 54.1. IE: trucks weighs 3500 lbs on the front tires, so... 3500/54.1=64.7 so that would be 64.7 psi. Divide that by 2, since you have 2 front tires, 33 psi.
5. Your tires need AT LEAST 33psi to hold up the front weight of your truck. Take this number and add a few pounds for security reasons and see how your tires wear.
6. Do the same for the rear. Yes, you will run a lot less in the rear tires when the truck is unloaded.
You can run more air in them if you like, but DO NOT run less than this number that you come up with. I do this with all of my trucks and my tire guy is always amazed at the mileage I get out of my tires.
Good luck!
David
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