Trailer Tire Questions
Steph_735
Reg. Dec 2003
Posted 2005-09-03 9:47 PM (#29947)
Subject: Trailer Tire Questions


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Posts: 76
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I have two questions about trailer tires.

First one is, what psi should i keep my tires at? I'm not sure but i think my trailer tires have a maximum of 55psi. When i checked them they were all between 42psi and 48psi. So i want to get them all set to the same number, but have no idea what psi i should have them at.

Then my other question is, my step-dad got a spare tire for my trailer, i was all happy and everything thinking he got me the right tire. He bought it from a tire/auto repair place in town. But the thing is the tire he got me meets everything except that the one number is 75 instead of 70. Now my tires on the trailer have the 70 number. But the spare has the 75 number and its also a light truck tire where as my trailer tires are trailer tires. But since its a spare i dont really care if its a light truck tire as if i do end up using it, it would only be that one time as i would get my tire fixed or replaced right away also. But does the difference between the 75 and 70 matter that much? Especially if its only a spare and i might not ever use it?

Sorry if i am confusing, i dont really know tires at all so thats why i am asking.

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Reg
Reg. Oct 2003
Posted 2005-09-04 5:13 PM (#29954 - in reply to #29947)
Subject: RE: Trailer Tire Questions


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Posts: 2689
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There are several other threads that address tire pressure.
The RIGHT pressure can be obtained from a load/pressure table for that tire size and profile. Weigh your trailer as loaded, each axle if practical, divide by two to figure the per tire load. It is OK to have a slightly different load and therefore different pressure for each axle's tire pair. The correct pressure is typically NOT the maximum inflation pressure, since that would only be appropriate if you were running the tire at it's maximum rated load and that is generally regarded as being not good.

Mismatched profiles (75 vs 70 (and probably ST vs LT or P)) is not something you would want to run on, though to get you "just down the road to a service station" it would be a lot better than having to run on a flat.
I'd spend the ~$75 to $90 and get a new GOOD spare that matches the other 4.
What am I saying ? I just DID spend about $80 for a tire and $50 for a rim that will probably never be used (-:

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