Tire presure for SRW with 19.5 G rated tires?

bishkoff wrote:
Just use the formula that the tire companys use to create the inflation table. Take the capacity of the tire and divide it by the max PSI, that will give you the amount of load per PSI that the tire can carry. Take the load on the axle and divide by 2, take that number and divide it by the PSI number you came up with in step 1 and that will give you the optimum PSI to run in your tire for optimum tire wear.
For Example a 235/80R17 has a capacity of 3085 @ 80 PSI, So 3085/80=38.56
that is 38.56lb of capacity per PSI in the tire.
So if I was running 5500lb on my rear axle 5500/2=2750 So 2750/38.56=71.31 PSI per tire for optimum tire wear. Hope this helps.

It's a close formula, but it does NOT match any inflation table I have ever seen. The formula does put more air in the tires than inflation table require, which is a good thing.. but that is not how the tables are calculated.

When inflation tables are not available it will get the pressure at least as high as it needs to be, and I have used it on many tires over the years.

Example...

My 245/70R19.5 LRG are 4500 @ 110. Based on math that is 3301lbs @ 80 psi, but based on the chart they carry 3640 @ 80 psi. The backwords math on 3640 would be 88 psi.

Using the same 235/80R17 you listed requires between 65 and 70 psi, not the 71.3 from the math.

Yes they are close, but it is not how it's calculated by the tire mfgr.