The continuing saga of tire pressure...

[goufgators]

My coach has been weighed and according to the tire manufacturer's PSI chart, I should be carrying 80 psi. But, when you (or I) have new tires installed, the tire company insists on pressuring up to the psi identified on the sidewall. Why is that? Do they consider it a liability issue if they put in a lesser amount of pressure as requested by the buyer? It's not a problem since, when I arrive home, I can then adjust the psi to whatever I want. But, just wondering why the dealer won't agree to a psi less than the sidewall amount. Any thoughts?

[topflite51]

Appears that most people have failed reading comprehension or haven't bothered even reading what it says on the sidewall of a 19.5 or 22.5 tire. Don't read what it says on your passenger car tire or light pick up tire and think they are the same, read what it says on a 19.5 or 22.5 tire, THEY ARE DIFFERENT.

If your tires on your MH are actually LT's then the pressure on your sidewall is the max pressure. If your tires on your MH are medium to heavy duty tires, 19.5 and larger the following is correct: Michelin RV TireGuide: Quote: "If you look at the tire's sidewall, you'll see the maximum load capacity allowed for the size tire and load rating, and the minimum cold air inflation needed to carry the maximum load." From page 6 of the GoodYear RV Tire and Care Guide: Quote: "How much air is enough? The proper air inflation for your tires depends on how much your fully loaded RV or trailer weighs. Look at the sidewall of your RV tire and you’ll see the maximum load capacity for the tire size and load rating, as well as the minimum cold air inflation, needed to carry that maximum load." From the August 2010 Motorhome Magazine "Tread Carefully" tire article: Quote: The maximum load capacity allowed for the size tire and load rating and the minimum cold air inflation needed to carry that maximum load are located on the tire’s sidewall. So if one has not weighed their rig, then the min tire pressure on the sidewall should be used until they have weighed their rig.

[slickest1]

parkmanaa wrote:
SLICKESG1, are you trying to insult me? Read my post a little closer.

Since bias ply truck/RV tire didn't have belts, of course I am speaking ONLY of radial tires, and what I am saying is based on experience gained throughout 40 years in the tire industry, working for a MAJOR radial tire manufacturer.
I, too have sat thru endless tech films, viewed thousands and thousands of radial tires being made, dissected radial tires, did scrap tire analysis, interviewed users, etc., etc., etc.
I'll just leave it there.

Actually no I was not trying to insult you or anyone else. The point I was making is the pressure stamped on the sidewall of a tire is there for a good reason.

[xctraveler]

Sam Spade wrote:

holstein13 wrote:
Therefore, the burden is on you to get your coach weighed and look up the manufacture's proscribed inflation pressures.

Conditions vary for sure but.............
IF you get the same size and load range tires with the same max. pressure rating, I don't see how the recommendation at less than max. load is going to be that much different, no matter what brand they are.

I use my RV more like a camper; it doesn't have much extra load.
Those who use one like a mobile house probably should pay closer attention.

Even use as a "camper", whatever that means, may include fresh water in the fw tank, propane in the propane tank, one or more people on board and food, not to mention a few sundries like dishes and cooking stuff and just a change of clothes or two. You might be surprised at how fast that can get over 1,000 lbs. Just for laughs a giggles, weigh it empty and then set up for a camping trip and weigh it again, with the people who travel with you on board. Michelin seems to think a couple of hundred pounds of load makes a difference, but what do they know? they just engineered and built the tires.

[Sam_Spade]

holstein13 wrote:
Therefore, the burden is on you to get your coach weighed and look up the manufacture's proscribed inflation pressures.

Conditions vary for sure but.............
IF you get the same size and load range tires with the same max. pressure rating, I don't see how the recommendation at less than max. load is going to be that much different, no matter what brand they are.

I use my RV more like a camper; it doesn't have much extra load.
Those who use one like a mobile house probably should pay closer attention.

[holstein13]

Sam Spade wrote:

holstein13 wrote:
Just imagine if a tire dealer had to weigh your coach and spend 15 additional minutes trying to find the proper inflation pressures for your coach. It simply isn't going to happen.

I just imagine that this was done AT THE FACTORY and doesn't need to be done again unless you make a major change to something.

That "method" has worked for me for about 60 years now with about a hundred different vehicles of various sizes and shapes.

Not ONE catastrophic tire failure; nada, zero, zip.

I know that OCD is a disorder......but recently I'm beginnning to think it is contagious.

Unfortunately, there are two problems with this approach.

1. The manufacturer doesn't know the weight of your coach. They sell empty coaches and can't predict what you'll add, and
2. Each tire manufacturer has different recommended inflation pressures for their tires. If you switch brands or styles, you may not have the same required pressures.

Therefore, the burden is on you to get your coach weighed and look up the manufacture's proscribed inflation pressures.

[Sam_Spade]

10forty2 wrote:
I believe that statistics will show that 75% of the people make up 3/4 of the population. Sorry, but this thread needed a little humor.....

And half the people are below average too. :B

[Sam_Spade]

holstein13 wrote:
Just imagine if a tire dealer had to weigh your coach and spend 15 additional minutes trying to find the proper inflation pressures for your coach. It simply isn't going to happen.

I just imagine that this was done AT THE FACTORY and doesn't need to be done again unless you make a major change to something.

That "method" has worked for me for about 60 years now with about a hundred different vehicles of various sizes and shapes.

Not ONE catastrophic tire failure; nada, zero, zip.

I know that OCD is a disorder......but recently I'm beginnning to think it is contagious.

[10forty2]

I believe that statistics will show that 75% of the people make up 3/4 of the population. Sorry, but this thread needed a little humor.....

For me, I tend to trust the engineers who designed the tire, (and not the average owner who just drives on them), to tell me what pressure to run in them. So...I, like many others weigh the coach and inflate the tires according to the chart. I learned the hard way about underinflation....haven't tried overinflation....don't think I will. 😉

[holstein13]

I'm concerned that many folks responding to this post are suggesting that the OP fill to the maximum pressure. Many have said that it's "safer" to inflate to the max pressure.

I'm here to give my opinion that that is simply not true. The safest pressure is the manufacturers' recommended pressure for the load on the tire. Over inflating a tire will result in less contact with the road and a corresponding decrease in handling ability and stopping ability. I highly encourage you to determine the proper tire pressure and inflate to the proper pressure. Don't rely on me or anyone else on this forum. Look up your manufacturers inflation chart for your tires.

Now back to the OP's comment. I believe that the reason tire dealers / installers inflate to the maximum is that it would require much more effort to determine the proper pressure and they believe that they are less likely to get in trouble for inflating it to the max.

I went to Spartan Chassis training a few months ago and they weighed all four corners. Afterwards, we spent about an hour and a half in class learning about tire pressure safety, tire ratings, sizes and finally how to read the inflation charts and determine the proper inflation for our tires. Just imagine if a tire dealer had to weigh your coach and spend 15 additional minutes trying to find the proper inflation pressures for your coach. It simply isn't going to happen.

[Effy]

A few things you can always take away from PSI threads


There are a lot of tire experts on this forum.

Oddly enough many of the experts don't share the same method. Heck, some have no method at all.

There is always doom and gloom with respect to PSI setting. Usually without a lot of documented proof and usually as a result of not using said expert's method.

Everyone's method they use is the best. No one ever seems to want to acknowledge someone else's method is better.

People are very passionate about tires and pressure. I smell and opportunity for a best seller "Tire Love".


Tires are forgiving. Based on the myriad of methods, variance in PSI settings, changes in ambient and tire temps and psi and all of them are not blowing up. Even using a method from a manufacturer, swings in PSI and temp have a HUGE range. Based on some posts they'd have you believe you are riding on Dynamite.

[the_silverback]

My logic is to get the MH weighted and inflate the tires to the pressure the tire manufacture recommends. Has worked for me for 11 years and 80,000 miles.

[Snomas]

I have always ran back @ 100 psi and front @ 100-105 psi. Never weighed the coach. Change the tires @6K mi. Last yr I bought a TPMS system and notice they read from 92 psi cold to 110 psi hot. Never

[tatest]

Tire and alignment shop that I use inflates to the pressures I tell them. They ask me. The maximum needed is also posted in the door jamb.

But the Honda dealer where I take my towed vehicle about once a year always overinflates, to maximum for the tire, although appropriate pressures are in the door jamb. I think they are assuming the tires will not be checked again until the car next comes to them for service, the TPMS complains, or one of them goes flat. For most of their customers, it isa fairly safe assumption. Gasoline filling stations stopped doing this for customers about 60 years ago.

[WILDEBILL308]

I am not going to tell you how I check my tiers or what air pressure I use. I will say I am not like the gentleman camped next to me last week who saw me doing my "magical" test of tier pressure. He told me I was wasting my time as he had the dealer check his tiers in the spring each year and there was no need to waste time doing it in between. Well all I could do is say GOOD LUCK.
Bill