Tire PSI
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Tire PSI
I read alot of people running 60 psi + a few years back and i know about the jam. But what do you run for different size/type of tires. For instance the above 60+ was for tires rated at max psi of 80 psi. Mine are 65 psi max E rated 127 load so not sure the above would translate.
You wouldnt run the same psi for a 80 psi max tire as a 65 psi max tire would you? What were the stock tires max psi? Is there a way to calculate what would be a good psi by load?
You wouldnt run the same psi for a 80 psi max tire as a 65 psi max tire would you? What were the stock tires max psi? Is there a way to calculate what would be a good psi by load?
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From: Media PA
The correct way to determine proper tire inflation is to weigh the vehicle to get each axle's weight, then divide that by two to get the load each tire sees. Then refer to the tire manufacturers inflation table to see what pressure is required for the amount of weight it has to carry.
And yes, once you change the tire size or load rating from stock the info on the door jamb becomes invalid.
And yes, once you change the tire size or load rating from stock the info on the door jamb becomes invalid.
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From: Media PA
I guess that your are saying that you can’t find the inflation tables from your tires manufacturer? If so, you can use the table from another manufacturer and use the info for their tire in your size and load range. What make, model and size tire are you on?
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They are Goodyear Kelly Safari TSR 315/75/16 load rating 127 and 65 psi max. I couldnt find any load info on them except the max load.. I will look into same load rating and psi from other manufacturers.. The question is do you inflate to psi for vehicle weight or is there a margin of error that is the sweet spot for psi.
For example i find the load to psi rating for said tires. I weight at 2000lbs per tire loaded. The psi rating for 2000lbs is 35psi. You set to 35psi or would you add some weight passed your loaded weight? say 500 extra lbs per tire and that would put the pressure at 40. I imagine it would always be better to have more psi then right at the limit?
For example i find the load to psi rating for said tires. I weight at 2000lbs per tire loaded. The psi rating for 2000lbs is 35psi. You set to 35psi or would you add some weight passed your loaded weight? say 500 extra lbs per tire and that would put the pressure at 40. I imagine it would always be better to have more psi then right at the limit?
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I have found 65 PSI works good for mine with Kelly tires that are rated for 80. But i have heavy front and rear bumpers, so my truck weighs a bit more than the average V10 Excursion.
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See the issue.. The 245/70/17 and 225/75/16 are 80 psi.. Mine are 65max.. But assuming you are running the 245/70/17 65 psi would equal a max load of 2600lbs that would equal about 38psi for me...
I found this info for same size tire, load rating and psi.. This is the specs:
35 psi 2535, 40 psi 2715, 45 psi 2950, 50 psi 3195, 55 psi 3395, 60 psi 3610, 65 psi 3860 ... What would you run? It looks like i would be fine on load rating 35psi or above, i guess i can do the chalk test?
This is toyo pdf that has alot of different tire sizes load vs psi... https://www.toyotires.com/media/3729/application_of_load_inflation_tables_20200723.pdf
I found this info for same size tire, load rating and psi.. This is the specs:
35 psi 2535, 40 psi 2715, 45 psi 2950, 50 psi 3195, 55 psi 3395, 60 psi 3610, 65 psi 3860 ... What would you run? It looks like i would be fine on load rating 35psi or above, i guess i can do the chalk test?
This is toyo pdf that has alot of different tire sizes load vs psi... https://www.toyotires.com/media/3729/application_of_load_inflation_tables_20200723.pdf
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From: TN
See the issue.. The 245/70/17 and 225/75/16 are 80 psi.. Mine are 65max.. But assuming you are running the 245/70/17 65 psi would equal a max load of 2600lbs that would equal about 38psi for me...
I found this info for same size tire, load rating and psi.. This is the specs:
35 psi 2535, 40 psi 2715, 45 psi 2950, 50 psi 3195, 55 psi 3395, 60 psi 3610, 65 psi 3860 ... What would you run? It looks like i would be fine on load rating 35psi or above, i guess i can do the chalk test?
This is toyo pdf that has alot of different tire sizes load vs psi... https://www.toyotires.com/media/3729...s_20200723.pdf
I found this info for same size tire, load rating and psi.. This is the specs:
35 psi 2535, 40 psi 2715, 45 psi 2950, 50 psi 3195, 55 psi 3395, 60 psi 3610, 65 psi 3860 ... What would you run? It looks like i would be fine on load rating 35psi or above, i guess i can do the chalk test?
This is toyo pdf that has alot of different tire sizes load vs psi... https://www.toyotires.com/media/3729...s_20200723.pdf
You decide what you like, but don't UNDERINFLATE tires on an Ex.
IF you run 35lbs, you do so at your own risk (and will likely get hurt or hurt someone else from that mistake.
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Load and Inflation tables are industry standard and set by the TRA, tire manufacturers make the info available but the manufacturer is irrelevant as psi is dictating by size and type. this one provided by toyo.
https://www.toyotires.com/media/3729...s_20200723.pdf
https://www.toyotires.com/media/3729...s_20200723.pdf
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Ok so why is 35 psi under inflation for the tires i provided? It would be a load rating of 2500 lbs per tire.. This would close to that of 65 psi of the other guys tires which would equate to 2600lbs per tire... Now i am not running this psi but trying to understand what is safe, are you saying only thing is safe is max psi? If not then where is the point that its not safe if you dont factor in the load and look strictly at the psi..
i am looking for knowledge here so please back your comments up with facts and sources. I provided the info i have found to contribute to others knowledge that might read this in the future...
i am looking for knowledge here so please back your comments up with facts and sources. I provided the info i have found to contribute to others knowledge that might read this in the future...
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From: Media PA
Ok so why is 35 psi under inflation for the tires i provided? It would be a load rating of 2500 lbs per tire.. This would close to that of 65 psi of the other guys tires which would equate to 2600lbs per tire... Now i am not running this psi but trying to understand what is safe, are you saying only thing is safe is max psi? If not then where is the point that its not safe if you dont factor in the load and look strictly at the psi..
i am looking for knowledge here so please back your comments up with facts and sources. I provided the info i have found to contribute to others knowledge that might read this in the future...
i am looking for knowledge here so please back your comments up with facts and sources. I provided the info i have found to contribute to others knowledge that might read this in the future...
I'm not 100% sure exactly what you are questioning here but just remember that the PSI (Pounds per Square Inch) is what is supporting the vehicle weight. Now think about how the Square Inches are determined, the taller and wider a tire (yours are both taller and wider than stock) the larger the contact patch or footprint, so more Square inches to carry the load. If the load remains the same with more Square Inches to carry it you will need less pressure to support the same amount of weight. That's why the bigger tires in the same load rating will only be 65 PSI max vs the 80 PSI max of smaller tires in the same load rating.
Find out your actual axle weights and follow the inflation table plus a couple of pounds for a bit of elbow room.
35 PSI on that size tire (315/75R16) will support 4670lbs per axle, if you are carrying less than that on each axle then you will not be underinflated at that pressure. Its perfectly fine to run different pressures on the front and rear if your scaled weights are different, like mine when towing heavy.
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Ok so i think i am grasping the concept here. In the pdf above it describes how to convert factory psi (door stamp) to a different tire size (page 9). My factory tires size is lt265/75r16 with psi at 45 front 55 rear which would give me a load rating of 2280lbs and 2625lbs respectively.
Now you match your new tire sizes to those loads, i am guessing 35psi is the minimum for my tires (since document doesn't have specs below that) and at that psi i have a load rating of 2535lbs which works for the front but needs to be adjusted for the rear. You subtract the two load ranges you are in and divided that by the subtracted two psi ranges you are in. My would be (2715-2535)÷(40-35)=36lbs per one psi. I need to make up 90lbs of load to be at factory specs in the rear which would be an extra 2.5psi from 35psi using the formula above which would be 37.5 (we will just round to 38 psi). So yes i would of been under inflated in the rear if running 35psi. This is all if going by factory psi specs... Anyways thanks for all that helped and i did learn some stuff here.
Now you match your new tire sizes to those loads, i am guessing 35psi is the minimum for my tires (since document doesn't have specs below that) and at that psi i have a load rating of 2535lbs which works for the front but needs to be adjusted for the rear. You subtract the two load ranges you are in and divided that by the subtracted two psi ranges you are in. My would be (2715-2535)÷(40-35)=36lbs per one psi. I need to make up 90lbs of load to be at factory specs in the rear which would be an extra 2.5psi from 35psi using the formula above which would be 37.5 (we will just round to 38 psi). So yes i would of been under inflated in the rear if running 35psi. This is all if going by factory psi specs... Anyways thanks for all that helped and i did learn some stuff here.
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I could of called them and they would say x and x psi but i wouldnt of learned anything from that. Now i can say this tire is safe at this psi to this psi then work on tire wear.. The safe psi was main concern due to these things weight..