Tire PSI?

[ldetsf]

I have a 91 25' excella 1000 dual torsion axle. AS said 60 psi in all tires. Like to know the truth. And, I'm towing with a 2005 Dodge diesel 4x4. Someone said I should max out the PSI (80) on the truck when I tow even if the truck itself is empty. Someone else said no, the truck psi should be as shown on the door, unladen. Same issue when the truck is loaded. So, what's a guy to do? Love to hear the facts from some of the forum experts. Thanks

[bobandcarla]

I run 60 in the trailer and on my truck I run 60 in the front and 80 in the back when I'm towing. I backed off on the truck to 50 all around for winter.

[moosetags]

I am running 65 psi in the Airstream tires. This is what is recommended in my owners manual. This is also the max pressure listed on the sidewall of the tires.

My TV is a 2005 Suburban 2500 running original equipment load range D tires. I run 80 psi on the rears and 50 psi on the fronts. These are the pressures recommended by GM on the driver door sticker. The tire sidewalls show a max of 80 psi.

I check and maintain these pressures religiously becuse low tire pressure caused excessive heat build up, and in turn can cause catistrophic tire failure.

[dwightdi]

Follow the AS recommendation for the trailer. If you are using proper w/d hitch then follow the truck manufacturers recommendation for that additional load imposed by the trailer. You do not need to go to the maximum pressure on the tires as they can handle the load with lesser PSI. Running high PSI in the truck tires only leads to harsh ride for the ocuppants and trailer.

[Hawk_Man]

First run a search on tire inflation, I believe this subject was already

discussed.

On another note. I used to own a 1996 Dodge 3/4 ton long bed that I used

as a TV. I ran my tire pressure on the rear at 80 psi and my front tires were

set at 50 psi, as per the vehicle recommendation, empty or loaded. Of

course that was with the recommended tires for the vehicle. If

you changed that factor then the tire pressure on the tire would be the only

thing you can run with. Currently on my Argosy 28, the tire pressure is set

at 60 psi. and it handles great . Again I suggest doing a search in the

forum's search engine. The information is here . Good Luck!

regards, Keith

[bryanl]

The biggest source of tire failure results from under inflation. That means bias your PSI high to be safer.

The 'optimum' tire pressure is carefully calibrated to the load on that tire and the manufacturer's specifications. Door panel and similar generic vehicle OEM recommendations are guestimates based on original equipment.

You will likely get better trailer handling with higher than optimum pressure. (especially in the tow vehicle)

Higher pressure may make for a harsher trailer ride which might create some problems. It may also cause extra center of tire wear although this isn't usually a problem with trailers due to low mileage over time. (it's the age that gets trailer tires)

Overdoing the load rating on tires is probably not a good idea. Match the tire load rating to the trailer requirements. This is usually load range C or D for Airstream trailers. C tires usually have a max psi of 45, D of 65, and E (like used in a lot of pickups) of 80 psi.

Sidewall max psi is for tires that have been sitting in the shade for a few hours.

You can tell you have enough tire pressure if the tires don't get hot on the road. Use an IR thermometer and check tires as well as wheels for indications of trouble. Tires usually run about 20F to 40F above ambient. If they get hotter than this, add air.

Easiest is to run your tires at max sidewall psi. That works for a lot of folks.

[overlander63]

I run 55 all around in the truck, and 50 all around in the trailer (Airstream said 45, on load range C tires, new tires are D.

[68 Overlander]

I would look at the manufactures load chart and go from there. It will mean weighing the trailer "loaded" if you want the real answer and will cost a few bucks for the public scale.
Not the quick answer I know but the truth is loading does make a difference. On the way to the scales, I would run minimum pressure for maximum weight.

[Cracker]

The tire pressures recommended by the vehicle manufacturer address the design capacity of the vehicle when fully loaded. If you're running a dually you may never reach anywhere near that capacity - especially on the duals. This topic has been discussed many times - but the only safe way to modify the manufacturers recommendated inflation pressure is to weigh the individual axles when loaded and then consult the tire manufacturers load chart. You'll never go wrong using the pressures shown on the door sticker - but pressures that are too high can make for an awfully rough ride, as well as shorten tread life! Note also that the tire manufacturer will show a minimum safe inflation pressure - regardless of load.

Our Airstreams don't enjoy a wide range of loading conditions - due to their limited CCC - and, at any one time they may also be experiencing a significant side-to-side difference in weight distribution. That said, I would, IMHO, always stick to the maximum recommended inflation pressure for the OEM trailer tires - and, again, weigh, weigh, weigh to make sure you're not overloaded!

[startrekker2001]

Tire pressure is one of the topics addressed by the RVSEF (RV Safety Education Foundation, Inc. 4575 Annette Court Merritt Island FL 32953). They are heavy into RV Safety. While at the Florida State Rally last year I had my tow vehicle and trailer weighed. They weigh each wheel and determine based on the tire manufacturers recommendations, the amount of pressure to carry on each ... AXLE ... .

Since most TV's and trailers are unbalanced side to side, (they should be within 10%) the pressure for the heaviest side on an axle is the pressure to be used on both ends of the axle.

It is true that running at too low a pressure will cause an early failure due to excessive flexing of the sidewalls which builds up heat and weakens the tire. Too high pressure will wear the tire in the center and actually decrease the amount of rubber on the road. The whole idea is to have the tire's designed footprint on the ground for best traction and tire performance, which is what we are all looking for. Which is why we should run the correct pressure for the load.

Another factor in tire failure is the age of the tire. Every tire has the date it was cast imprinted on the tire. For tires cast before 2000 it is a 3 digit number. the first two digits are the week it was cast and the last digit is the year. For tires cast in 2000 and later, the date is 4 digits. The first 2 are the week and the last two are the year. I just purchased a 1992 Cadillac with 18000 miles on it. The tires had a date of 202. Just for grins I took the car to several tire dealers and out of 5 tries only one could tell me the correct date which was week 20 of 1992!!! The tires were 12 years old!! I have replaced them since. The point of all this is that tires have a shelf life of 5 to 7 years. Beyond that the material in the tire has broken down to the point that failure is imminent. When you purchase tires, insist on seeing the cast date. If it is more than a year old, reject it and tell them why. Unless of course they want to knock 20% off the price of the tire...

In many cases where people experience tire failure they cant tell you how old the tire was or what pressure they carried. It is usually, "oh, just what the guy at the tire shop put in, I guess" or "gee the tires all looked good and the 1996 unit only had 30000 miles on it."

I have developed an Excel spreadsheet that when the design weights, ie GVW, GVAW, for the TV and trailer and the GCVW for the TV are entered plus the results of the TV and Trailer actual weights on each tire, calculates the correct pressure for each axle on the TV and Trailer, the tongue weight, and highlights any value that is out of spec. It also tells the remaining capacity at each weight point and for the TV and trailer.

It uses the tire data for that can be found on-line at any manufacturer website. The industry is standardized to the point that for the tire size and type, the weights and pressures are nearly the same.

One last thing. There is a difference between the sidewall construction of truck/passenger tires and trailer tires. You should use only tires that are prefixed with ST as in ST225/75R15.

The upshot of all this is... use the CORRECT tire pressure. It will extend the tire life, tread life and your life.