air pressure tire question ?

[Tom48]

Originally Posted by padcarroll

I would check with the tire or TT manufacturer. As mentioned by rebeltown, each vehicle has a recommended psi by wright.

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The trailer manufacturer tire pressure rating is normally the maximum TIR tire is rated to handle. I have upgraded to a higher load rated tire twice before and always run cold pressure at or within a pound of the maximum rated on tire. Lowering pressure evidently increases heat and thereby increases failure defeating the purpose of upgrading to the higher rated tire.

[Tireman9]

Originally Posted by Tom48

The trailer manufacturer tire pressure rating is normally the maximum TIR tire is rated to handle. I have upgraded to a higher load rated tire twice before and always run cold pressure at or within a pound of the maximum rated on tire. Lowering pressure evidently increases heat and thereby increases failure defeating the purpose of upgrading to the higher rated tire.

^ correct

Lower psi also increases the Interply Shear which is trying to tear the belts off the body of the tire.

You can Google Interply Shear tires if you want to learn mor or read a technical paper on the topic.

[SailorSam20500]

This discussion really intrigued me. After looking at a bunch of sites on the inner-web (and burning a boat load of time), I ended up sending an e-mail to one of the big 3 Tire manufacturers yesterday asking specifically about air pressure for travel trailers because the guides I've seen seem to talk about Class A/C units (RVs). Asked specifically about the inter-ply shear issue. I got a reply today! No comment on shear. Their reply was that tire manufacturers supply charts that show the minimum air pressure needed to carry the weight of the trailer and they strongly recommend getting weights for each tire. On an axle basis all tires on an axle should have the air required based on the tire/side with the most weight.
Then, really interestingly, they went on and stated - "actual weights may fluctuate significantly between trips" because of this they stated "inflating the tires to the pressure required to carry the maximum load, is in your best interest".

That makes sense, I doubt anyone weighs their rig at the begining of every trip,

So, for me, I'm not going to worry about looking up tire pressure guides any more - I'm filling to the max weight pressure posted on my tires.

[DouglasReid]

Originally Posted by rebeltown

I'm not familiar with trailer tires but car tires only give a Max air pressure for the tire and the recommended tire pressure for the car is quite a bit lower and listed on a sticker on the front door jamb. Don't trailer manufacturers give recommended tire pressures for their trailers?

The recommended pressure is the MAX for the tire you have installed. Lower pressure means lower load carrying capacity-leading to blowouts.

Simple, inflate to max, Always.

[ofishlbusiness]

You are right passenger and light truck tire show the max recommended tire pressure and the max load at that pressure the tire is designed for. The door jam shows the vehicle manufactures recommended air pressure for that application with the recommend tire size shown. Generally because there are far fewer tire sizes available for trailer application, and one tire size may cover several trailer sizes, the max recommended psi is used. Plus by using the max pressure your tires roll on the pavement easier, thereby making the trailer pull easier and can increase fuel mileage towing.

[Tireman9]

Originally Posted by DouglasReid

The recommended pressure is the MAX for the tire you have installed. Lower pressure means lower load carrying capacity-leading to blowouts.

Simple, inflate to max, Always.

^ x2 for trailers.