Tire Pressure

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Mar 30, 2023 | 07:21 AM

#61

RidgwaySD

Cargo Master

Joined: Jul 2021

Posts: 2,969

Likes: 2,407

From: Ridgway, CO

Quote:

Originally Posted by scraprat

All that inflating and deflating with algebra figuring gets you the same amount of tread life as I get and I carry over 1500# all the time. I see 50k mile life all the time with my tires with 65psi front and rear.
I even had one set of Les Schwab brand tire go 62k miles but those were pricey tires.

Tire rotation is important for the longest possible life. Especially for someone like yourself that is pulling trailers and plowing.

Since I do not carry 1500 lbs all the time my truck gets way better mileage when just commuting. just the 800 lbs I carry most of the winter kills the mpg. Way too many days on bombed out gravel roads to run high pressures so it is worth it to air up and down for me. I really do not obsess over the math. Just figure it out when the truck is new, it isn't hard to remember 50/42 empty, 60/52 plowing, 50/65 towing. So I could do 60/65 all the time but the difference in ride off highway is pretty substantial so I take the time for the adjustments.

Dec 26, 2024 | 07:03 PM

#62

Vanteer

5th Wheeling

Joined: Jan 2024

Posts: 28

Likes: 9

From: Oceanside

Quote:

Originally Posted by jadatis

Because in reaction #36 loadindex 129 was given AT 80 psi, I made a pressure/ loadcapacity list for it, as example for topicstarter. This with the system, I described in post #32.

So look acurately determined axleloads back in my list, and use the cold pressure in front of it, and still acceptable comfort and gripp.

This acurate determining of the axleloads in your situation is the most tricky part in it all, and your responcibility. So succes with that.

Then maximum reserve for things like :
1. Unequall weight R/L on the axle.
2. Inacurate reading of pressure scale, and pressure loss in time.
3. Incidental extra load.
4. To 10. Etcetera

So can be used for every tire with singleload LI 129/ 1850kg/4079lbs maxload AT 80 psi. And speedcode Q or higher, on singleload axle.
So dont add reserves or devide by 2 yourselfes, all done for you.

Cold psi/ 90% of axleloadcapacity
20 psi / 2088 lbs
22 psi / 2270 lbs/ lowest inEUR
24 psi / 2451 lbs
26 psi / 2632 lbs/ lowest in US
28 psi / 2812 lbs
30 psi / 2991 lbs
32 psi / 3170 lbs
34 psi / 3348 lbs
36 psi / 3526 lbs
38 psi / 3703 lbs
40 psi / 3880 lbs
42 psi / 4056 lbs
44 psi / 4232 lbs
46 psi / 4407 lbs
48 psi / 4582 lbs
50 psi / 4757 lbs
52 psi / 4931 lbs
54 psi / 5105 lbs
56 psi / 5279 lbs
58 psi / 5452 lbs
60 psi / 5625 lbs
62 psi / 5798 lbs
64 psi / 5971 lbs
66 psi / 6143 lbs
68 psi / 6315 lbs
70 psi / 6487 lbs
72 psi / 6658 lbs
74 psi / 6829 lbs
76 psi / 7000 lbs
78 psi / 7171 lbs
80 psi / 7342 lbs/ referencepressure
82 psi / 7512 lbs
84 psi / 7682 lbs
86 psi / 7852 lbs
88 psi / 8022 lbs
90 psi / 8191 lbs/ maxload x2 and sometimes given maximum allowed cold pressure.

Can be that other referencepressure is used for a E-load tire, have seen 75psi, 77psi, and 83psi, mostly on European version of LT is C- tyre, C for Comercial, so dont assume automatically 80 psi for E-load/ LRE/ 10 <acronym title="Page Ranking"><acronym title="Page Ranking">pr</acronym></acronym>(Plyrated as is used in Europe).

Jatadas - Thanks for all the info. I have Bridgestone Dueler LT 275/65/R20, load range E, Max load 3750 at 80 PSI, on my 2024 F250. So that is a max load of the front axle of 7500 lbs, way over the sticker of 5200lbs GRVW for the front axle.

Does the above chart work for me? If not, would you generate one for me?

I plan to lower the TMPS threshold to 55f / 50r. Empty I plan to cary 400 - 600 lbs just to smooth out the ride.

My front GAWR is 5200 lbs, and Ford says 60psi. The chart says 55 lbs would be fine.

Thanks for your help.

Dec 27, 2024 | 02:33 AM

#63

jadatis

5th Wheeling

Joined: Sep 2012

Posts: 45

Likes: 6

Quote:

Originally Posted by Vanteer

your tire has loadindex 126maxload 3748 lbs AT 80 psi , so lower then the 129 of that other list.

here list for your tire.
the 5200 lbs GAWR front gives also 60 to 62 psi in my list, but I think that is coincidence, and they did not like to go lower then 60 psi, calculated with officiall used formula in US with no reserve build in , as is done , would give lower pressure.
mij list gives 90% of calculated loadcapacity for the pressure, calculated with a tighter formula , that leads to lower loadcapacity.
I determined tis 90% given for max 160 kmph/99mph to give maximum reserve, at wich comfoet and gripp is still acceptable.

Li 126 / maxload 3748 lbs/ 1700 kg AT 80 psi

Axleloadcapacity/ cold psi
1750 lbs/ 18,0 psi
1918 lbs/ 20,0 psi
2086 lbs/ 22,0 psi
2252 lbs/ 24,0 psi
2418 lbs/ 26,0 psi
2584 lbs/ 28,0 psi
2749 lbs/ 30,0 psi
2913 lbs/ 32,0 psi
3077 lbs/ 34,0 psi
3240 lbs/ 36,0 psi
3403 lbs/ 38,0 psi
3565 lbs/ 40,0 psi
3727 lbs/ 42,0 psi
3888 lbs/ 44,0 psi
4050 lbs/ 46,0 psi
4210 lbs/ 48,0 psi
4371 lbs/ 50,0 psi
4531 lbs/ 52,0 psi
4691 lbs/ 54,0 psi
4851 lbs/ 56,0 psi
5010 lbs/ 58,0 psi
5169 lbs/ 60,0 psi
5328 lbs/ 62,0 psi/ gawr 5200 lbs
5486 lbs/ 64,0 psi
5644 lbs/ 66,0 psi
5802 lbs/ 68,0 psi
5960 lbs/ 70,0 psi
6118 lbs/ 72,0 psi
6275 lbs/ 74,0 psi
6432 lbs/ 76,0 psi
6589 lbs/ 78,0 psi
6746 lbs/ 80,0 psi/ referencepressure
6902 lbs/ 82,0 psi
7059 lbs/ 84,0 psi
7215 lbs/ 86,0 psi
7371 lbs/ 88,0 psi
7527 lbs/ 90,0 psi/ sometimes also given max cold pressure.