Just weighed and have PSI question

["007"]

---------A SHORT HISTORY OF WHY THIS POST WAS DEVELOPED---------

---------Not sure why everyone gets all flustered over tire PSI pressures.-------

This thread starts at post #1 naturally and you can see why "tnedator" had frustrations leading up to why I have placed this post for information as to how and why your PSI for your tires are very important for your safety and your family's.

Before we continue you may have some questions you want answered as "tnedator" did, here are a few with answers by Tireman9.

# 1 --- Is there a difference between a TT ( TOWABLE RV) and a MH in fingering my PSI.---- ANSWER

# 2 -- Other than harsh ride, what are the downsides to over-inflation.---When you receive your coach from your dealer the tire pressures will be high, maybe tire side wall pressures? ------ ANSWER

# 3 --Should I add PSI above my minimum PSI ?----- ANSWER -- #1 --- #2 ---- # 3 Finale Result

CONSIDERING NEW TIRES SOME THINGS TO CONSIDER --by PackerPower

GOT NEW TIRES NOW HAVE VIBRATIONS, WOBBLE WHEN DRIVING by Dhilbe

- WHEN IS A SHIMMY A SHIMMY by GLWilliam58

MORE INFO ON TIRE INFLATION ---- YOU STILL NEED YOUR COACH WEIGHT FOR YOUR TIRES TO HAVE THEIR PROPER TIRE INFLATION.

Your coach is empty, you drive it home everything rattles, coach rides hard over bumps and its just miserable to drive.

The coach is now in your hands to put in the correct PSI for your tires.
You load your coach compartments spreading out the load as even as possible than your personable items, food, generally all the items you will use on the road.

As your doing this the springs and suspension will be feeling the pressure build up as you add a full tank of fuel, LP gas. fresh water in tank, full water heater and the bodies that are going to ride in coach including the dogs if you have them.

You drive to a local scales ride may have changed for the better or worst.
You get it weight and drive home next morning your ready with the air pump and air gage to put proper PSI in your tires, night before you have figured the proper PSI by using your tire MFG's tire inflation tables with the weights you got at the scales,

HOW TO DETERMINE THE CORRECT PSI ---- courtesy of the TIREMAN9

Now you proceed to add or decrease the air in your tires.
Your doing this in the morning because you would check same time when on road and your tires are at their coolest in the morning.
You will find that in the mornings on road checking the tire PSI's are going to hold pretty much the same with no variation, in the colder months you will see more variation from the cold temps.

So you do all this and decide to try out on the road and you notice no more rattles, softer ride, better control and a much happier coach and driver.

When your driving your coach the tire PSI will increase from 15 to 20 PSI as the tires heat up, all your tires were at the proper tire pressure when you checked them in the morning and now is not the time to check them because they have heated up.

Their are to sides to tire inflation the correct PSI as you applied to your tires and the result of what happens when you do not have properly inflated tires a soft tire blow out link provided by the TIREMAN9.

OTHER IMPORTANT TIRE INFORMATION ---- DOES COLD WEATHER EFFECT TIRE PRESSURE

Now for example my coach a Newmar gas 37' long, 22.5 tires came to me at 100 PSI all tires.
After getting coach weight four rear tires, 85 PSI, front tires at 90-95 PSI, the variation depends what was loaded in front compartments.
We have some people that like to add another 5 PSI for safety, I never did it in my coach's.

DP's will have larger tires and higher PSI's but the same procedures are used to get proper PSI's..

This is how I have done tire pressure for 6 different coach MFG's with different tire MFG's never had a tire blow out in many miles of travel.

Some other advise is place a plywood board under the footprint of your tires to separate tires from surface the tires are setting on, you can use plastic cutting boards found at SAM's or other stores, your tires will last longer for it.

You need your tires cared for, for peace of mind and many miles of good use.

Enjoy your motor homes and many miles of safe travels.

MICHELIN TIRES --- GOODYEAR TIRES --ANOTHER TIRE SIDEWALL

DISCUSSION YOU MAY FIND OF INTEREST --- TSPS SYSTEM

ALL THESE LINKS FOUND IN QT's 1 & 2

[Crasher]

Originally Posted by 007";3850868]As you can guess I am no expert either never measured the tire inflation before a blow out while driving.
All I can say over time side wall expansions may eventually weaken the tire for a blow out.
Did you read [B][URL="http://www.irv2.com/forums/f103/tire-pressure-115624-2.html#post1091032

this link[/URL][/B] provided.

When I was "learning" how to manage and care for my RV tires, I consulted a Michelin tech regarding the pressure buildup from carrying the load. I explained that the minimum for my steer tires was 110 psi and that I inflated to 115. The sidewall says 120 psi for maximum load. On a 100* day on hot asphalt, the pressure would climb to 142psi. His response was that as long as the cold psi was at or above the minimum required to carry the load, I should not be concerned about how high the "Hot" pressure went to. The tires are designed to deal with that and it will not weaken them. He emphasized maintaining the correct "cold" pressure. The exception would be the added heat that a faulty brake or bearing might add. I currently have 43,000 miles on the tires and they appear fine.

["007"]

He was correct as long as your cold psi is below side wall psi on tire, your safe.

Many start with the side wall tire pressure and leave it at that pressure, the link on side wall print psi's should get people to think better of that thinking.

If you ever have some tire work done and tire removed from rim take a look at the inside of tire they should look like new as mine did with 40,000 miles, couldn't believe it, thought there would be some bands showing through white interior with the abuse tires get on our roads.

[4x4van]

If a tire dealer EVER says to inflate the RV tires to the # on the sidewall without at the very least consulting the tire placard, it's time to start going to a different tire dealer.

["007"]

YES SIMPLE I AGREE

The placard everyone is now talking about is the coach after build by MFG of weigh added to the chassis and what they think you will be loading for weight fully loaded, you still get your coach weight and use PSI's from your scale weight tabulations with the tire MFG TABLES.

["007"]

Now the biggest problem is the confusion people ask in how to calibrate the correct PSI using the tire MFG's tables.

Here is another link I have saved by Tireman9 as to how to accomplish that task.

I hope with all the links, provided in my posts,you all have a better understanding of the responsibility you have for correct usage of your tires and protection of your family's.

Enjoy your lifestyle and many miles of safe travels.

[Tireman9]

Originally Posted by tnedator

Ok, so I went by a CAT scale today. After I weighed and the wife went in to get the printout the kid said he'd never had an RV get weighed and she said a truck driver was there and said the same thing. Thought that was interesting.

Anyway, so, I have a Thor ACE 30.3. it was 6340 front axle and 9960 rear axle.

Since I don't have a four corner weight, my understanding is I would divide the front weight by 2 (3170) and the rear by four (2490).

According to the Goodyear chart, the minimum is 80 PSI (the ford placard says 82 PSI) and that's for 3640 for a Single wheel and 3415 for a dual.

So, do I just stick with the minimum of 80? Go with Ford's 82, or go 5 PSI higher as I've read recommended some places, which would be 85 PSI?

As I see it I'm way below (1,000 lbs front axle and 4,000 lbs rear axle) the weight listed for the minimum PSI for my Goodyear tires (245/70R 19.5)
3415

OK jumping past all the other posts.

When a tire company stops showing lower tire pressures that are telling you to not run lower than the lowest pressure shown.

It is unusual to have a MH as light as yours is when the MH is full of water, fuel, propane and all your travel stuff. many folks find that when they check their MH on a scale they are overweight and exceed the GAWR and/or the tire load capacity.

The suggestions for +10% or +5psi are based on an inflation shown in the tables which should be considered the MINIMUM inflation to run. The plus is to give a margin so you are not chasing the inflation as the pressure changes with changes in Ambient temperature.

Given that 80 is your MINIMUM inflation I would suggest you consider running 82 to 84 psi cold F and similar rear.

[Tireman9]

Originally Posted by 007";3851526]Now the biggest problem is the confusion people ask in how to calibrate the correct psi using the tire MFG's tables.

Here is [B][URL="http://www.irv2.com/forums/f103/what-tire-pressure-186375-2.html#post1903233

another link[/URL][/B] I have saved by Tireman9 as to how to accomplish that task.

I hope with all the links, provided in my posts,you all have a better understanding of the responsibility you have for correct usage of your tires and protection of your family's.

Enjoy your lifestyle and many miles of safe travels.

Here is the new link

http://fifthwheelst.com/documents/Br...eWeighForm.pdf

[Crasher]

Originally Posted by "007"

Thanks Tireman

Not sure how we can convince people to weight their coach's and not just use sidewall info or placard info.

I've asked before, but how about a sticky written by Roger or does that create a potential liability for the forum and moderators?

["007"]

This information link will be posted in New Rig Showoff, Class A Forum, TECH INFORMATION, Newmar forum, NEWBE's new to irv2 , 5th wheel forum links for starters.
It will be referred to when misinformation is posted by members or members seeking help for proper tire inflation's for both TT's and MOTOR HOMES.

I will be open to the Tireman for any adds he may identify, his links are identified in the large post.

[kedanie]

All of the federal regulations are only applicable to manufacturers. None of them apply to the end user. This was confirmed by Tireman9 in a recent post. So, you are correct in your application of tire inflation charts provided by the tire manufacturer, also provided by Tireman9.

Keith

[tnedator]

Originally Posted by Tireman9

OK jumping past all the other posts.

When a tire company stops showing lower tire pressures that are telling you to not run lower than the lowest pressure shown.

It is unusual to have a MH as light as yours is when the MH is full of water, fuel, propane and all your travel stuff. many folks find that when they check their MH on a scale they are overweight and exceed the GAWR and/or the tire load capacity.

The suggestions for +10% or +5psi are based on an inflation shown in the tables which should be considered the MINIMUM inflation to run. The plus is to give a margin so you are not chasing the inflation as the pressure changes with changes in Ambient temperature.

Given that 80 is your MINIMUM inflation I would suggest you consider running 82 to 84 psi cold F and similar rear.

Thanks for the reply, that was the conclusion I came to on my own. Before leaving on a trip earlier in the week, I aired them all up to 84.

My F53 is rated at 18,000 ----7000 F / 12,000 R

The CCC on the 18,000 lb chassis for my coach is nearly 2,600, so being below max isn't too surprising (considering how many coaches have 1,000-1,500 CCC).

The goodyear chart on the G670 tire would still have the rear tires 400lbs below the minimum entry on the chart (3415 @80PSI) if the rear axle was at max.

If the front was at max it would be 140 lbs per tire below the minimum entry (3640 @80PSI).

So, unless I'm missing something, on this coach, it would have to be an extremely overloaded coach to move out of the minimum column on the Goodyear tires (especially since most of the additional coach weight (water/holding tanks/cargo) would be rear of the center line.

That said, rather than running them right at the minimum entry, I figured it would be best to run them at 84 to give some breathing room above the minimum (cold mornings, pressure gauge variations, etc.).

["007"]

OK some observations when ever there is a tire pressure post posted on this or other forums on irv2 a large " OH NO NOT AGAIN" GROAN IS HEARD, this is what happens, remarks are made by people and they are given points for them, some posts members will never see, some member may be move off forums for a time or just band from the forums, this is what is going on in the back room.

This has been going on for years that I have been on irv2.

This is not what irv2 is here for, its suppose to be a friendly exchange of idea's and solutions of peoples problems.
In most cases whats highlighted is carried out by members on these forums so why all the fuss when a tire pressure question is asked.

I'll give my take on maybe why, we have ----- TT owners ----- MH owners that never had a TT ---- TT owners that moved up to a MH ----- MH owners that still think they still own a TT -- maybe there is and other I can not think of right now.

THE POINT IS TIRE PRESSURES ARE FIGURED DIFFERENTLY between the RV's owner's involved.

I have friends that own MH's and suffer blow outs all the time and their tires look good at the pressure they are using and not a soft tire look that Tireman9 says will most likely cause a blow out, I agree with him on the soft tire link he provided.

After looking at their damaged MH, which can be extensive, I asked if they ever got their coach weigh and they said know.

Also looking at that soft tire link you can get a blow out from tire nail puncture, that builds up heat as pressure lowers, valve stem problem or just age of tire which brings up side wall crack situations.

I have seen soft tires on TT's and informed people to check their tire pressure, that they were not even aware of.
We pulled a sleeper pop-up for the children we had and I always use the TP on sidewall of tire, yet suffered a blow out, maybe because of age of tire.

Running through all the threads pass few days I came upon one I should have saved where Tireman was answering a members question where the member was unaware of tire pressures in using a MH and Tireman had some harsh words for that dealer.

Maybe Tireman9 will answer some of the differences between PIS's of TT's and MH's to clear up some of the misconceptions people have.

The master post # 15 I have been compiling will be posted in certain forums with the traffic that will warrant new members noticing TP problems.

TT's AND 5TH WHEEL TIRE INFLATION INSTRUCTIONS

[Tireman9]

Originally Posted by Tireman9

Here is the new link

http://fifthwheelst.com/documents/Br...eWeighForm.pdf

Here are the instructions from Goodyear on how to learn the correct inflation but they do not include the pictures on how to calculate which end of an axle is heavier but they do tell you to figure out which end is heavier.

So for those that visit a location that can give you the individual axle end loads such as RVSEF you can go straight to the Load / Info tables.

If you only can find a platform scale and need to do the calculations you can use the drawing provided by Bridgestone.