A new number to figure into the tire equation calculation

[jonrjen]

A week or so ago I had started a thread about ST vs. LT tires on a 5th wheel.

Here is a link to that thread: http://www.forestriverforums.com/for...t-52212-3.html

I received a pretty good education from all the replies. Some of the replies focused on the tire load carry rating of LT tires not being as great as that of the ST tires. Seems that the ST tires were rated somewhere at or near 3420 pounds where as the LT tires were rated at only 3086 pounds each. I did confirm these numbers and agreed that the LT tires were not equal to the ST load numbers and would result in a total drop in carrying capacity of 1400 pounds give to take a few.

So today I took the Wildcat up to have it state inspected and noticed that one of the tires had a slow leak. I had filled the tires up to 80psi a week ago and before taking off to get the safety inspection one of the tires only read 30psi. So I checked all four tires and filled them up to 82psi. After passing the safety inspection I asked them to remove the subject tire and inspect it for either an air leak in the tire or the wheel. Turns out that somewhere along the line the tire had been plugged which was not holding pressure. I had the tire dismounted, plug pulled and the tire patched. While the tire was off of the wheel I thought I would look for the MAX PSI rating on the wheel. This number was no where to be found.

However, to my surprise the wheels themselves are stamped made in China, with a MAX WEIGHT Rating of 3200 pounds each. Which made me stop and pause and ask, what is the big deal on having a tire that will carry 3420 pound of payload when the wheels are only rated for 3200 pounds of payload? I guess you could just as easy say well the axles are rated at 6000 pounds, so 2 wheels rated at 3200 pounds exceed the carrying capacity of the axles. So then you add in the fact that each tire will carry a load of 3420 pounds of payload each. So now each 6000 pound axle now has the tire load capacity of 6840 payload ability.

Now taking everything into proper context, and using the "chain is only as strong as the weakest link" formula, what's the point of so much focus on the tire weight rating.

Now I'm not saying I am starting to agree with the conspiracy of "ST" tires being a marketing ploy from the tire industry......but......just but at this point.

[Airdale]

Originally Posted by jonrjen

A week or so ago I had started a thread about ST vs. LT tires on a 5th wheel.

Here is a link to that thread: http://www.forestriverforums.com/for...t-52212-3.html

I received a pretty good education from all the replies. Some of the replies focused on the tire load carry rating of LT tires not being as great as that of the ST tires. Seems that the ST tires were rated somewhere at or near 3420 pounds where as the LT tires were rated at only 3086 pounds each. I did confirm these numbers and agreed that the LT tires were not equal to the ST load numbers and would result in a total drop in carrying capacity of 1400 pounds give to take a few.

So today I took the Wildcat up to have it state inspected and noticed that one of the tires had a slow leak. I had filled the tires up to 80psi a week ago and before taking off to get the safety inspection one of the tires only read 30psi. So I checked all four tires and filled them up to 82psi. After passing the safety inspection I asked them to remove the subject tire and inspect it for either an air leak in the tire or the wheel. Turns out that somewhere along the line the tire had been plugged which was not holding pressure. I had the tire dismounted, plug pulled and the tire patched. While the tire was off of the wheel I thought I would look for the MAX PSI rating on the wheel. This number was no where to be found.

However, to my surprise the wheels themselves are stamped made in China, with a MAX WEIGHT Rating of 3200 pounds each. Which made me stop and pause and ask, what is the big deal on having a tire that will carry 3420 pound of payload when the wheels are only rated for 3200 pounds of payload? I guess you could just as easy say well the axles are rated at 6000 pounds, so 2 wheels rated at 3200 pounds exceed the carrying capacity of the axles. So then you add in the fact that each tire will carry a load of 3420 pounds of payload each. So now each 6000 pound axle now has the tire load capacity of 6840 payload ability.

Now taking everything into proper context, and using the "chain is only as strong as the weakest link" formula, what's the point of so much focus on the tire weight rating.

Now I'm not saying I am starting to agree with the conspiracy of "ST" tires being a marketing ploy from the tire industry......but......just but at this point.

You sort of answered that when you found only 30 psi in one of your tires. They are flexible and NEED excess load capacity reserves to increase their survivability.

BA