Are Our Tires REALLY that sensitive?

[10forty2]

I know I will roust the ire of many a tire aficionado, as well as those who will claim expert knowledge from years of traveling and RV'ing and quasi-engineering or actual engineering status/certification....I assure you I mean nothing personal towards anyone and I don't mean to walk on the waters of your knowledge because I have and will benefit immensely from it..... BUT with that said....

Are our tires really that sensitive? I mean, these things cost $400-$1K each and we talk about and treat them like they are made of glass or fine crystal. I certainly understand the need to ensure safety by checking certain parameters, but honestly? I must admit, after 2 tire failures within 2 months of each other, I'm a bit paranoid, myself. The first was just an old tire that I failed to verify its age when I bought the coach...my fault. The second was a new tire but turned out to be a factory defect....it happens from time to time with anything a human-being manufactures.

But can it really be so critical that the pressure stay within 1-psi of the recommended "weight table?" Do we need to have professional scales in our basement bins so we can weigh each wheel every time before we pull out so we know exactly what pressure the tire should have? And if we do, should we have two identical sets of scales so that we can leave one in the basement bin where the other one stays so we know exactly how much it weighs? Should I calculate how much weight I will gain over the course of my vacation depending on how well I eat so I know how much to compensate the air pressure? Do I have to become a meteorologist so I can predict the temperature of the places I travel so I can ensure that I have the proper pressure for the weight that I measured in that climate?

I admit it... I'm a Class A Newbie, but it just can't be this complicated...can it?

Your discussions please....:?

[tropical36]

Just a small word of caution for those who choose to air their modern tires to the max inflation level printed on the tire and have an older coach with wheels that are rated for no more than 90psi. You don't hear of it happening much, but I wouldn't want to be the one inflating it. It's one thing to have a tire explode, but try to imagine a wheel doing so. Like I said rare, but if and when it does happen, I'm not so sure if calling 911 would help much.

[wa8yxm]

Short answer is no, 1 PSI is a bit.. er,, Anal as they say, 10% is a more accurate acceptable range or better +/-5%,

But the closer to ideal the longer your tires will last.

Here is a suggestion:.. DO you know the meaning of the word interpolation?

For example: at 100 PSI a 22.5" Mitchlin XRV single tire can hold 8910 pounds, and at 105 PSI the same tire is good for 9220,

but what happens if you have 8980 pounds on the wheel? (Interpolation can give you a pressure but the chart is only done in 5 PSI steps, oh, I'd use the higher pressure (105) for that one).

And many like to add 5 PSI just for fun.

And yes, for ideal tire life (never an issue on an RV) you need to be +/- 1 PSI

HOWEVER, this has to do with tread life,, Most RV tires are relaced not due to tread life but due to shelf life,, Mine still have many thousands of miles of tread life left, but are due for replacement due to age.

[Rodz]

My MH came with 110lbs in the tires. I could feel every crack it the road. I now have 80lbs in them and it rides like a dream. I don't care what the charts say. I've owned MH's for 40 plus years and have had 2 tire failures, both from running over something in the road. When I had a DP I was told to run 110 in them. My new gasser is 10k lbs lighter and I'm told to run the same 110 in them. Not seeing the logic. A chart is someone's opinion. I don't believe everything I read.

[WILDEBILL308]

One other thing that I didn't want to add to the above reply as not to confuse anyone. Be Shure your tiers are of the right load range. This is a problem if you are at the top off the weight range for your tiers. I had a problem with a Class C I had. The front tiers kept having problems including a couple of blow outs. The coach was well under weight. I finally figured out the problem. The manufacture had used the stock tiers that came on the van chasse it was made on. The original 16 in load range D tiers were overloaded from the get-go. I moved up tp load range E and solved the problem.
The other big thing not mentioned is speed rating. When looking at tier manufactures web sites I was surprised to find some only rated for 60 mph some 65 yes there are 75mph rated tiers.
Bill

[WILDEBILL308]

Harvard wrote:
Twice a year, in the course of 3 days, we travel from Latitude 52N to 32N on Jan 1st and back again in March. That means a OAT temperature gradient of as much as 60 DegF enroute.

I go for the recommended Min load PSI before departing the North and Max PSI rating before departing the south. As such, I do not adjust the pressure enroute, but I do routine temperature checks.

I would set the tire pressure as recommended. Weigh the coach ect and set your pressure as recommended. when you get to your destination check the pressure and adjust as necessary. Checking temp is one way but better is check pressure before starting out in the morning.
Bill

[mike_brez]

crasster wrote:

mike brez wrote:
I weighed my rig once loaded up how it will travel. Inflated tires 5lbs over what inflation chart says for my weights. Check them every time before we leave. Have a tire pressure monitor system of some sort. At home when we park we park on rubber mud flaps.we don't cover our tires but is most likely a good idea.

If they are that sensative, better not stop at too many burger joints with the family and get back in the coach!

🙂

Seems like a teeny amount of over weight. Usually I find I am way under weight for tire specs.

Sorry I don't get it.:h

[crasster]

mike brez wrote:
I weighed my rig once loaded up how it will travel. Inflated tires 5lbs over what inflation chart says for my weights. Check them every time before we leave. Have a tire pressure monitor system of some sort. At home when we park we park on rubber mud flaps.we don't cover our tires but is most likely a good idea.

If they are that sensative, better not stop at too many burger joints with the family and get back in the coach!

🙂

Seems like a teeny amount of over weight. Usually I find I am way under weight for tire specs.

[Raymon]

To Bikeboy57,

You stated "Moisture is the enemy of the steel belts." How does the steel belts become exposed to moisture when the belts are vulcanized between layers of rubber? In my opinion the steel belts only become exposed to moisture due to tire wear. If the belts become exposed they will rust which is not good. Also, steel belts exposed to brine created from applying salt to the roads during winter, not only rust, but corrode very quickly.

You also stated "Driving the tire and getting it up to temperature dissipates the moisture,..." What moisture are you referring to?

Ray

[J-Rooster]

I've been RVing since 1976 and of yet I never had major tire problems. I'm not into all the technical gadgets etc. I air my tires at 100 psi before I head out on a trip and before I return from a trip and that is it. Same as when I was driving a Semi. Just as important is other tire care that no one else is talking about. Your rubber tires are very sensitive to road dirt and grime, heat, cold, moisture, going over curbs and holes in the road surface, overloading, dirt roadways, and I see this at every campground I go to RV's up on blocks and the block surface does not cover the complete tire surface which can result in inner side wall break down and damage which you can't see. Great Question

[rgatijnet1]

JimM68 wrote:
I set the alarm on my tpms to 75% of my cold tire pressure. When / if the tpms alarmgoes off, I stop.

Are you saying that when your tires which would have a 100psi cold tire pressure leak down to 75psi, you stop? In other words 25 psi below the minimum cold tire pressure.
You're kidding, right? :h

[JimM68]

There is a lot of discussion on this. And that is good, losing a tire in a violent manner is a scary and expensive thing.

I'm a technician, not an engineer. I gave up long ago wondering "WHY?" I want to know "what broke?" "how to fix it?" and hopefully on a very good day, "how to prevent it from happening again.

I've had 2 motorhomes over 7 years, and during that time I've lost 3 tires.

Today, I run a good tpms. I weighed my rig, checked my weight tables for my tires, and set my pressures at 5 lbs above minimum for the weight. I set the alarm on my tpms to 75% of my cold tire pressure. When / if the tpms alarmgoes off, I stop.

The last time I bought tires, I had them install solid metal valvestems, pointed out in all cases. My TST flow thru sensors screw right on the inner duals. The outer duals have 3" solid extensions then the (non flothru) sensors. and the fronts have non flo thru sensor screwed right onto the stems. This eliminated my previous problem of leaking extensions.

And now I just forget about my tires. Every spring coming out of storage, I check and adjust the air pressure, and the rest of the season I ignore them. Unless the TPMS alarm goes off.

[Pogoil]

My tires and brakes get a lot of my attention. As a long time CDL. holder I do not want to hurt my family or another family.

That said it is up to you the driver as it is your responsibility to do tire checks and brake checks. My recommendation is to go to your local DMV. and pick up a CDL. driver book, for free and read it to understand the responsibility you have chosen driving a large vehicle.

Do your brake tests often and check your tires often is the best advice I can give. We should be proud to be held to a greater standard of safety that most likely all states will and should require in the future.

Pogoil.

[deandec]

It is not complicated. We just make it so.

Somebody paid their lawyers a lot of money to assess the liability of publishing a table of inflation guidelines (and oil change guidelines) that the engineers calculated.

I suspect the lawyers generously covered their butt and the Corporate butt before allowing those guidelines to be published.

[VinCee]

Thanks rgatijnet1! Good info. Not being a daredevil of any type I do check the pressure of my RV's tires before every single trip. I have a digital gauge and the stick type for trucks which is the one I go by. I always check them at rest stops, visual and touch, and when we arrive at our destination. Even going and checking on the rig at its outside winter storage lot I'll walk around and inspect the tires.

[rgatijnet1]

VinCee wrote:
My friend who is a mechanical engineer told me he stored the bike in a heated garage away from any electrical source, what ever that meant.

He was telling you that to indicate that it was not stored near any electrical motor which is a source of ozone.
People that live in high ozone areas will experience more degradation of their tires than those that spend most of their time in a low ozone area. Most online weather sites will tell you what the ozone level is in your area.
Ozone and rubber are just not compatible.