Cold pressure means before hauling the trailer any significant distance.  But unless you have a compressor at home, you 'll just have to fill the tires at the service station.  

Since trailer tires don't have to steer or drive... Just inflate them to the max pressure as marked on the tire sidewall. You'll want to check them before any long trip.  Tires will slowly lose pressure over time.

I read this all the way through three times...are you recommending not to use the maximum cold pressure, or to use the maximum cold pressure?

The tire should be filled to its maximum cold pressure as indicated on the sidewall. As it is being used, the air will warm, expand, and increase the internal pressure beyond its initial pressure. This variance is built into the operating pressures allowed by the manufacturer.

If the tire is being used, and the pressure is checked and found to be high, some people will let the excess air out. This will result in an under inflated tire, and should not be accomplished.

That is why tire pressures should be checked when cold.

Gard

I agree with you Gard...I was just trying to figure out exactly what Paul was telling us.

If you don't want to run the maximum pressure.... Weigh the trailer loaded and inflate the tires accordingly...

The original poster was speaking about trailer tires.  You seem to be speaking about truck or vehicle tires.  These are separate issues.  Your TRUCK tires have to steer or drive.  The truck manufacturer's tire pressures are figured for traction, ride, load and wear.  Follow their recommendations.

Trailer tires are just along for the ride.  Air them to max cold pressure as stamped on the tire sidewall.

There are two factions within this forum; those who run their truck tires at the maximum pressure as indicated by the tire manufacturers, and those who follow the recommendations of the truck manufacturer.

I choose the tire manufacturer's recommendations. I can do so, because I don't normally use my truck in an unloaded configuration, which would usually cause the center threads of the tires to wear more quickly. I enjoy even tire wear patterns, and I don't have to re-air when I'm ready to pull.

On my truck and trailers, I always run at the maximum rated tire pressures. This provides the largest load factor, and the least amount of road friction, which results in a lesser amount of heat build up, and the best mileage.

Gard

Probably not..... The one's that turned air out were probably the ones that had tire problems on the way home. Imagine what that under inflated tire looks like making that short, tight turn at the filling station all the while climbing up and over the curb.... If it don't pull the bead off the rim, then it will probably break a cord/belt in the tire..... It probably won't blow out today, no, it's going to wait untill you're in a big hurry, going to an event, with the kids, all the horses, pick-nik gear, on a Sunday, in the boonies, then all of a sudden that under inflated tire is going to go BOOM...... Hey! GOT....  http://usrider.org/

Keep you tires properly inflated and replace them every 5 to 6 years...

No.  The difference from 75F to 100F is not enough to over-inflate a tire.  Over-inflated tires do not blow out due to heat.  Under-inflated tires blow out due to heat.  But, not because of the ambient air temperature or because the pressure gets too high.  Under-inflated tires blow out due to heat build-up in the rubber caused by excess flexing.  Like retento said, the people who let air out of their tires at 100F probably are the ones having tire problems in the first place.

I always go to the max pressure printed on the tire.  But, there used to be a member here that recommended following these charts:

http://www.goodyear.com/rv/pdf/rv_inflation.pdf

While we're on the subject, what does everybody think of this?

http://www.goodyear.com/rv/pdf/marathon_gen_info_032806.pdf

Goodyear says that industry standard says the trailer tires are rated for 65 mph at the max pressure, but if you want to run up to 75 mph, you can increase the air pressure by up to 10 psi over the rated pressure, provided your wheel will handle it.  Does anybody actually over-inflate their tires in order to run at higher speeds?

I agree with the chart. The lower the pressure the less rating that you have. If you know you are carrying less than max weight, you could lower your pressures  for a smoother ride. Most people don't know their weights well enough or pay enough attention to do this. Me personally, I am going to check it cold and inflate to the cold max everytime. I'd rather be safe on the load rating.

I hadn't ever seen this. I don't pay attention (although I should) to the max speed rating. I know that they are there and I know that I am running it faster than rated, but when it comes to load, I tend to overkill on my tires...so theoretically if I inflate to cold max, I am good to 2730 going 75 mph vs. 3000 at 65 mph on a Marthon tire. I only have one trailer that I use very much that it would make much difference, but I don't use it long hauls. 50-75 miles at a time. Kind of evens out, don't you think?

I run truck tires on my trailers, so I don't pay attention to the speed ratings of ST trailer tires. If my truck is safe at speed, so will be my trailers.

I've been to many schools on tire maintenance. They were directed and taught by the FAA, various tire manufacturers and my employer. They all agreed on several points:

1) More damage is done to tires by under inflation than over inflation.

2) The heat damage to the sidewall bead area laminations is irreversible.

3) The cord areas are more subject to physical damage with low air pressure

4) In extreme low pressure, overloaded circumstances, the sidewalls can be damagedt by the rims.

5) Any tire that has been used with under inflated pressures (these pressures will vary according to the ply rating) are subject to change, will not be reused, and have holes drilled in them to effect a scrap value.

6) Once your maximum cold pressure has been satisfied, the air pressure should not be readjusted

Gard