PSI

Is there any evidence that an over-inflated tire runs cooler than a properly inflated tire?

Drew_K wrote:
I respectfully disagree that running max PSI is bad advice for an RV. Dramatically running over pressuring the tire isn't good, but you're making a compromise when setting tire pressures: ride quality will be better with a lower pressure and be harsher as you increase PSI. Adding more pressure theoretically reduces your contact patch, but unless it's drastic, you won't notice a difference. Perhaps higher pressure will wear the middle of the tires more.

But given the higher failure rates for RV tires vs regular tires, I'd rather run max PSI and have the extra load capacity, at the expense of perhaps a slightly harsher ride and wearing out the tires a little earlier. Even then, I've had to replace RV/trailer tires due to age before they wear the treat out.

In the end, I don't think it's wrong to run at the exact tire PSI for your RV weight, but I also think there is merit to running at max PSI, which is what I do. And I don't think anyone will argue that it's good to run underinflated (unless perhaps if you're on sand, before some smart ass tries to make that argument).

X-2

Less heat build up running max recommend air pressure. I myself always ran the air pressure listed on the tire.

Dennis M M wrote:
Max PSI is bad advice. The correct way to do it is to weigh the vehicle and use the tire manufacturers weight/pressure charts to determine the correct pressure.

From the Michelin RV Brochure:

THE IMPORTANCE OF TIRE PRESSURE
The most important factor in maintaining the life of
MICHELIN® RV tires is making sure they are always
properly inflated. Incorrect air pressure for the weight of
the vehicle is dangerous and could cause things like
premature wear, tire damage, or a harsher ride.

An underinflated or overloaded tire will build up more
heat that could go beyond the endurance limits of the
rubber and radial cords. This could cause sudden tire
failure. Underinflation will also cause poor handling, faster
and/or irregular tire wear, and can decrease fuel economy.

Overinflation, on the other hand, will reduce the tire’s contact area with the road, which reduces traction, braking ability, and handling. A tire that’s overinflated for the
weight it’s carrying is more prone to a harsh ride, uneven
tire wear, and impact damage.

X2!!!!

More is not always better, My 5er has 16" "E" rated tires 3,042# ea. my 5er puts between 9,000# to 9,500# on the trailer tires, so I run 70 psi not 80 psi.

One size does not fit all!!!

Same with the TV,I adjust the rear tires when towing and not towing. Max pressure is for MAX LOAD not all LOADS!!!

bdpreece wrote:
None really. You need to go to a scale and get loaded weight then go to tire manufacturers charts for correct PSI.

IMO, this is exactly correct. You want an inflation pressure that gives the best tire life and best road grip.
Adjusting the tire pressure according to weight does that.
However, ALL the tires on a trailer should be inflated to the same pressure.

Tires--
IMHO, buy the highest rated rims, highest rated tire d,e,g that will fit on your RV rig. Some subscribe to the idea of buying the lowest price tire available in order to avoid spending extra money. Good theory but generally speaking means that you have greater possibility of blow outs/ tire seperations and more often.
Good Year Tire man with "G" rated tires:):):)

At the risk of being nontechnical and simple, check the capacity of the wheel. There should be a max pressure rating stamped on the inside of the wheel. Aluminum wheels will typically be able to handle higher pressures than steel rims, or so I'm told by the tire dealers I have dealt with. That taken into consideration, I suggest using the highest weight rated tire you think you need then air them to the max stamped on the tire sidewall.

Max sidewall pressures for tires on a trailer works best. Folks are always asking for some sort of document from a reliable source so here we go;

fifthwheelstreet.com

Step #5..
Selecting the Correct Tire Pressure for Your Trailer
We at Fifth Wheel St. no longer recommend adjusting trailer tire inflation pressure below the maximum load PSI rating molded on the sidewall (and only if the wheel/rim is appropriately rated) regardless of the measured scaled weight of individual tire or axle positions for all multi-axle trailers.

However, we do strongly recommend weighing individual trailer tire positions to ensure none of the axles or tire positions are overloaded. Reports have shown that trailers do not have equal weight across all tire positions. Some RV load configurations may reveal as much as 20% difference between the front and rear axle. This especially true for Toy Haulers. It is possible that mismanaged trailer load distribution will cause one end of an axle or a tire to be overloaded. It has been stated, but never confirmed by any RV Weighmaster, that there are many RVs traveling on the road with at least one tire or axle side overloaded. The only way to ensure tires and or axles are not overloaded is to weigh each tire position on your trailer. Unfortunately, attempting to obtain accurate individual tire position weight is practically impossible at all truck scales. View our list of recommend RV Weighmasters here.
- See more at: http://fifthwheelst.com/step5.html#sthash.FIAc3k0Z.dpuf
.......................................................................

And from our resident tire engineer Tireman9 blog (rvtiresafety.com) on the subject;

"The manufacturers do not take into consideration the side to side unbalance, as to do so would require them to provide larger (more expensive) tires. The other thing RV industry does not take into consideration is the forces to the tire structure due to running close axle spacing. Engineering analysis shows that when turning corners the forces trying to tear the tire apart can be over 20% higher in multi-axle applications than with tires at the corners of the vehicle.
The only options for the trailer owner are to up-size the tires (if there is room) or up-rate and increase inflation (if a higher Load Range tire and stronger wheels are available). Lacking the above being sure to run the tire at the inflation shown on the sidewall (i.e. max) will slightly decrease but not eliminate the overload forces.
...........................................................................
and anther professional source;

rvsafety.com

Tire Load and Inflation Ratings

Note: Towable – Travel Trailer/ 5th Wheel owners Due to the severe use conditions experienced by tires when axles are very close together – tire industry experts recommend maximum (sidewall) inflation pressure for towable tires unless this causes a sever over-inflation situation (20psi+), often referred to as the ‘basketball effect’. If this is your situation allow a 10 – 15psi safety margin above the minimum required inflation pressure.
............................................................

And we all have seen Goodyear max sidewall recommendations for tires on a trailer.

And we all know about Carlisle max pressures for their new tire warranty.

Now if someone has over tired the trailer then at some point less pressures will be needed. Not knowing any of the OP tires particulars we can only guess his trailer needs a 65 psi rated tire.

This is no different than the tow rating of any TV...a specification/rating/etc
are just that for whatever it is written for

Molded on the tire info is for 'that' tire, period

Trailer manual is for that trailer and the OEM tires it is supposed to
come with. But the molded in tire info trumps the manual or anything
else....period

That molded in spec is for the max weight, which is also molded in
the same area of the tire sidewall

So unless you are running 'that' tire at molded maximum side wall spec
the best tire PSI is lower...meaning do NOT go over the sidewall
weight rating

What that lower PSI is what I think you are asking help in figuring
and that means you need to know the actual weight that tire is
carrying...meaning you need to go out and weigh your trailer...axle by axle

65 is what i would run.

JKwock wrote:
Trailer says 50psi, tires say 65psi, tire store says 5 less than max which is 60psi. Who is right?

65psi will give you the best service that particular tire can deliver.

Anyone that says differently doesn't know what they are talking about.

If in doubt, contact the manufacturer.