I want to make sure I'm setting the tire pressure correctly on my Fleetwood Storm. Here are the numbers:Front GAWR - 7,000 lbs.Rear GAWR - 12,000 lbs.Actual Weight Ratings Loaded for a Trip:Front Axle: 5640 lbs.Rear Axle: 11500 lbs.Bridgestone Tires: 245/70R 19.5Min. Tire Pressure 80 lbs.Max. Tire Pressure: 110 lbs.I looked up on the Bridgestone Web site and found the followingAt 80 PSI for Single Tire it is showing 3525 lbs. At 80 PSI for Dual Tires it is showing 3415 lbs. If I take the front Axle actual weight and divide by two I get 2820 lbs. based upon the information above, I would set the tire pressure to 80 lbs. cold (or a little more to keep above the 80 lbs min. PSI on the tire).If I take the rear axle actuals, and divide by 4 I get 2875 lbs.based upon the information above, I would set the tire pressure to 80 lbs. cold (or a little more to keep above the 80 lbs min. PSI on the tire).I know that I should weigh each tire individually, but I currently do not have access to a scale to make sure a weighing. Am I calculating this correctly, so that all tires should be set to between 80 lbs. and 84 lbs. ?

IMO put max psi in all tires when towing... keeps heat down period......

Your calculations look correct to me. Based on those numbers, I'd run 80 psi on front and rear tires. Did you have all of the occupants on board when you were on the scales? If not, maybe compensate for the additional weight.Fred

Your calculations are correct. If you feel any one of the tires getting warmer than the others the loading may be asymetrical so try adding 5psi. lawrosa wrote:IMO put max psi in all tires when towing... keeps heat down period......Nothing like a reccomendation that goes against every tire manufacturers recommendation. Does too much pressure keep heat down....yes it does, but there are plenty of negatives. Too much pressure will reduce tire life from uneven wear, it will reduce traction, it also increases the susceptibility to road hazard, as well as makes the ride worse. There are far more reasons not to run max pressure at any load than there are to run max pressure at any load.

lawrosa wrote:IMO put max psi in all tires when towing... keeps heat down period......Your in the wrong thread. lol

So you are counting that your RV is perfectly balanced side to side?I would be running 100 PSI in all the tires. If you like running more than 70 MPH, then increase the pressure an additional 10 PSI, so that the tires will run cooler.Chances are that the drivers side slide outs would make that side heavier than the other side.Fred.

Making Sure I'm Setting My Tire Pressure Correctly

mowermech
Explorer
May 23, 2015
Unless you compare your pressure gauge to one that has recently gone through calibration, you still don't know if it is accurate. "New, high quality" does not mean accurate!
When I was an active aircraft mechanic, ALL of my PME (precision measuring equipment) had to have an annual calibration check. That included my tire pressure gauge (a Blue Point from the Snap-On truck). It passed every year.
Sadly, after nearly 30 years of use and abuse, my half inch drive torque wrench failed calibration, could not be recalibrated, and had to be replaced!
Although my tire pressure gauge has not been verified since I retired, I still trust it.
Harvey51
Explorer
May 23, 2015
The next question is how do we know our pressure gauges are accurate? I took my best one, four ears old, to visit my mechanic friend at his workplace where he keeps a quite new, high quality one. It said mine was reading 60 when the pressure was 75 psi. Turned out the best pressure gauge I had was a digital one I got at a dollar store. Next best was an old spring one I inherited from my dad and cleaned/lubricated. The three of them agreed last summer.
AH64ID
Explorer
May 19, 2015
Grit dog wrote:

While I agree with you 100%, apparently the vehicle mfgs don't since the godd@;);$mn TPMS indicator is set to trigger at barely under 80psi on my last 2 new Ferd 250s.
I do always run full psi in trailer tires, and in the op's case, I'd run 80-90front and just air up the rears to the max when loaded at 11-12k rear axle weight.

Don't let engineering by lawyers fool you.

What happens when a guy loads up his F-250 to the RAWR and blows a tire from under-inflation? On a truck with TPMS it is the trucks fault right?? From a warranty and liability standpoint it is easier to set the TPMS to 75 psi than it is to expect the drivers to do their due diligence and air their tires up when needed.

TPMS is now set to match the max pressure needed for AWR, which is BS for most users but oh well... lawyers and their effects on our life.
Grit_dog
Navigator
May 19, 2015
AH64ID wrote:
Your calculations are correct.

If you feel any one of the tires getting warmer than the others the loading may be asymetrical so try adding 5psi.

lawrosa wrote:
IMO put max psi in all tires when towing... keeps heat down period......

Nothing like a reccomendation that goes against every tire manufacturers recommendation.

Does too much pressure keep heat down....yes it does, but there are plenty of negatives.

Too much pressure will reduce tire life from uneven wear, it will reduce traction, it also increases the susceptibility to road hazard, as well as makes the ride worse.

There are far more reasons not to run max pressure at any load than there are to run max pressure at any load.

While I agree with you 100%, apparently the vehicle mfgs don't since the godd@;);$mn TPMS indicator is set to trigger at barely under 80psi on my last 2 new Ferd 250s.
I do always run full psi in trailer tires, and in the op's case, I'd run 80-90front and just air up the rears to the max when loaded at 11-12k rear axle weight.
C-Bears
Explorer
May 19, 2015
Here is what I do (or did). First of all I weighed my rig (combination) when it was loaded and ready for the road, including full fuel and passenger. Then I made sure I even had the correct load range tires on both my truck and trailer.

Next I order a TPMS and installed it, which takes about 10 minutes and $200+ to do.

Based on my weights and ratings I set all my air pressures during the morning hours when the temperature was around 70 degrees and all the tires were in the shade.

Then I just sit back and enjoy watching my TPMS. It is the only way to really know what your tires are doing as you tow in different conditions and at different speeds.
Ivylog
Explorer III
May 19, 2015
" Who do you believe" You can listen to Lawrosa (doubled down on max pressure) who has never posted in the Class C or A forums and pulls a small trailer with a S10 PU... OR you can listen to someone who has owned three Class A's and has been on here for 11 years.

"How do you know what is correct" It's actually simple math. At 80 psi (the min pressure to keep the tire on the rim and not flex too much) you are 500 lbs under what the tire can carry. If still in doubt, then do what Lawrosa says and put 110 lbs in all the tires and take it out and compare how it handles when you had 80 psi in all your tires. Steer left/right and the back end will be all over the place with 110 in them.

OP, before you waste that much time doing the above, I did an advanced search on "weighing " in the Class A section for some better reading. You could even post your question there for answers from people that actually own MHs, not trailers that are close to overloaded and need max pressure in their tires.
time2roll
Nomad
May 19, 2015
I would go minimum to 90 psi cold all around and see how it rides. Go up to 100 or 110 if it improves the ride or handling.
cold = morning before you roll and before the sun hits the tires.
lawrosa
Explorer
May 19, 2015
foolish comments here IMO...

I did temp testing and such on my tires... Put the max psi in IMO.. I said it before but someone made fun of me and said I was in wrong forum..

Read here especially PSI area...

http://www.trucktrend.com/features/towing/1407-understanding-tire-load-ratings/
KRex-Tampa
Explorer
May 18, 2015
I had forgotten I had looked this information up on the tire site. Thanks for the reminder and the confirmation my math (based upon the information I have) was accurate. I will check to make sure I'm not going over the 10% tire pressure increase due to heat.
AH64ID
Explorer
May 18, 2015
KRex-Tampa wrote:
Yes, it was weighted filled loaded with all passengers, full tank of gas and 1/2 tank fresh water.

The scary part is the various thoughts about the right pressure amount. Who do you believe and how do you know what is correct? Anyone have a link to an authoritative web site (i.e from a tire company or RV company)?

You already found it as indicated in your first post.

There are basically 2 types of people when it comes to tire pressure. Those who believe in running the propper pressure and those who think sidewall max is the proper pressure for any load.

You appear to be in the first group and your math was spot on.

Do not worry about air for 99 mph as your tires are likely only rated for 75 mph.

Do check the pressure after an hour or so of driving to make sure you aren't getting a big pressure rise from heat. Once you are sure you aren't then not the cold pressure and go camping.