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....:?

[VinCee]

I don't know jack stuff about anything other that what I do, or can opine on. My Georgetown tells me I should run my 22.5 Michelins at 95 lbs. So I run my rig at 95-100 lbs. cold. Why do I need to weight my rig and how many really do? Or worry if two bikes that weight what, 40 lbs., will make a difference! I do agree (in theory because I know nothing) that folks RV'ing in the Southwest especially will have a whole different set of circumstances to deal with when you have air temps over 100 degrees days on end and only imagining what the road temps must be some days. An acquaintance of mine has a 1988 Winnebago with the original tires! I asked Gene, who for fun races sprint cars and is maybe the best mechanic I know how could he feel safe driving the Winnie. He just told me that they weren't cracked or dry rotted, he keeps them inflated to recommended pressure even while stored over the winter. In 2003 I bought a 1977 Kawasaki motorcycle from a friend with 3600 original miles on it. I was amazed that the original 36 yr.old rubber was still on the bike. 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. I drove the bike for another 2000 miles before I noticed they were finally showing signs of cracking and replaced them with new Dunlops.

[Harvard]

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.

[phillyg]

I don't believe one or two pounds makes any difference. But, some people don't do anything with their tires and that's a problem. Failing to start the day with properly adjusted tire pressure is taking an unnecessary risk. Running on old tires, especially STs used on most trailers, is taking as risk. In both instances where I had a blowout, it was on a Class A with a six year old tire, and a FW with a four year old tire, thus supporting the anecdotal evidence that Class A tires will last six years and ST tires will last three years. That doesn't mean someone else won't get ten or more years out of a set of tires, but it's the point at which I'll be thinking about new tires.

[10forty2]

All good points and discussions....thanks! It just seems to me that we make it overly difficult to have a good time on our really expensive toys. I just can't imagine that tires are as fragile as we make them out to be. People travel literally millions if not billions of miles on them every year. I definitely know what damage they can cause when they fail... I'm into two tire failures for a little over $6K right now. Fortunately I have insurance that is helping pay the repair bills, but I just don't want to believe that the most important component of highway safety...tires...is so sensitive that I need to treat them like glass. I don't want to ride on pins and needles, wondering if yet another blowout will happen. If that's the case, then I'm going back to hotel rooms. Most of your answers confirm that our tires really aren't that sensitive, but definitely should be part of the overall safety checks every day before driving.

Keep the opinions up... I'm learning lots here!

[Executive45]

The two brands indicated above are Goodyear and Michelin. According to their ads they impregnate the rubber with compounds specifically tailored to the RV market. I'm not an engineer and I've not delved into proving or disproving their claims. I have, however, visited both Goodyear and Michelin test tracks and was impressed with the testing they do on all their tires including the RV sized ones.

As far as your other "points"....well, the word "overthinking" comes to mind. It would be interesting to poll the RV folks as to how many have NEVER weighed their rigs. I think the number would surprise you. Take that and notice how many rigs cruise down the highway at 70-80 mph on tires rated at 65mph and you might start seeing why tires fail.

Tires are an important subject as a tire failure on an RV can have disastrous results.

I think you've received TWO very good answers already.....just my opinion, your mileage may vary....Dennis

[Snomas]

I put 100 - 105" in my 6 tires (w/tire gage readings) and have only had problems as follows:
-lost air in a tire while @ daughters driveway. Found a nail and had it repaired.
- lost air in a tire while in campground. Found a leak in the extension I added.
-lost air in a tire while in storage. Found problem w/ new TPMS sensor leaking & still trying to figure out cause of this problem.
I have never weighed the MH and replace tires every 5-6 yrs. On my 3rd set now. My new TPMS system has given me readings as low as 92 psi when cold and up to 122 psi on on tire on this recent 1200 mi winter trip.
I have always checked the tire pressures before starting a trip to be sure they are in the 100-105 psi range. The new TPMS seems to read the tires about 6 lbs lower than my gage when cold.

[Ivylog]

I go 5 over because I do not stop when there are very strong cross winds. They can shift enough weight to increase the tire temps on the down wind side by 5-10 degrees even with 5 extra psi. Guess I could calculate how much a 30 mph wind pushing on 420 sq ft would be but it's a bunch more than extra people or bikes or $200 at WalMart.

[tropical36]

10forty2 wrote:
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....:?

Story short, weigh each axle and provide a cushion of 15psi over what it says on the inflation chart to take care of all the variables.

[DanTheRVMan]

amandasgramma wrote:
My husband's opinion, and he's been "into cars" for almost 65 yrs, believes people are the cause of tire problems. 1) factory defect, 2) overloading the rig, 3) old tires, and 4) axle alignment problems. The last one has caused our friends to pay for many tires. They had an axle break on their TT. It was "welded" back together, but looking at it, you can see the tires aren't lined up right.....

The idea of scales on each wheel area is good......but don't see that happening. We pull into weigh stations that aren't open and weigh our rig.

You're overthinking the weather thing/air pressure....:) Relax, enjoy. After 45-50 yrs of traveling, we've not had a tire blow yet on a rig.

oh --- I KNOW there will be someone that comes on here and says I'm all wrong.. You'll get 1000 different ideas..... 🙂 This is just our opinions.

I would add a 5th cause - HEAT. If you live in the south you will have more problems as tires do no do well in the heat.

[DanTheRVMan]

bluwtr49 wrote:
Going out on a bit of a limb here but if you look through the multitude of posts on this subject you may notice that two brands stand out when the variety of different issues are discussed. Since both of these tires are supposedly designed specifically for the RV market it would suggest that the brand of tire you happen to be running may be more sensitive than others.

You might also form the opinion that if tires are going to be replaced on a time schedule it might be wise to buy the least expensive as possible since the incidence of failure appear to less than the high priced items.

1. why not name a brand instead of having everyone guess or search?

2. Not sure which brand you think is the problem but all tiffins come with michelin. I really have not checked other brand mh tires. But what ever has the largest market share will also have more tires out there under inflated by owners and more failures posted on forums. Simply looking at lots of brand X failures is overly simplistic without looking at other parameters.

Not trying to endorse or detract from michelin as I do not know which tire is best or worst.

[rgatijnet1]

bluwtr49 wrote:
Going out on a bit of a limb here but if you look through the multitude of posts on this subject you may notice that two brands stand out when the variety of different issues are discussed. Since both of these tires are supposedly designed specifically for the RV market it would suggest that the brand of tire you happen to be running may be more sensitive than others.

You might also form the opinion that if tires are going to be replaced on a time schedule it might be wise to buy the least expensive as possible since the incidence of failure appear to less than the high priced items.

I figure the people that buy the cheapest foreign tires are too embarrassed to post that they had tire problems. :R

[bluwtr49]

Going out on a bit of a limb here but if you look through the multitude of posts on this subject you may notice that two brands stand out when the variety of different issues are discussed. Since both of these tires are supposedly designed specifically for the RV market it would suggest that the brand of tire you happen to be running may be more sensitive than others.

You might also form the opinion that if tires are going to be replaced on a time schedule it might be wise to buy the least expensive as possible since the incidence of failure appear to less than the high priced items.

[dewey02]

Bikeboy57 wrote:
Good Morning.

I am a certified engineer, although not a tire engineer. My career was in the manufacture of medical devices where safety is of paramount concern. The load inflation tables were generated by hours of testing by lab rat engineers where the design of the tire was verified to meet safety requirements. What that means is that the tire was tested at the load, inflation, and speed listed in the inflation table and met or exceeded the requirements. If you ask the engineer what would happen if you deviate from the load inflation, you will get two answers. One, sponsored by the company attorneys and the prudent answer, is I don't have any data to predict what will happen sir. The second off the record answer is likely to be, higher inflation pressures over what is recommended in the table do not degrade safety, and inflation pressures below recommended for the load degrade safety performance in proportion to how much lower than recommended the tire is inflated. That being said, ambient air temperature, driving speed, road surface, age of tire, and history of tire all factor in to it's safety. No one can generate a accurate predictor using all those factors of what a tire may or may not do.

Given the high consequences of a blow out on a truck tire, the easy no worries approach is inflate them to the max pressure on the sidewall, weigh the coach to ensure it doesn't exceed the load rating, and replace them every five years.

However, higher than needed inflation pressures make the coach ride rougher and handle less than ideal. Replacement intervals can very widely. A tire could have less than a 100 miles but have been setting in the full Florida sun on wet sand when compared to a five year old tire with 50,000 miles that had been driven weekly. If there are no cracks in the high mileage tire, it may be more safe than the one that has not been driven. Moisture is the enemy of the steel belts. UV light is the enemy of the rubber. Driving the tire and getting it up to temperature dissipates the moisture, and causes UV protectants to bloom to the surface of the tire.

By far the biggest danger is running an underinflated tire for the load. In order to prevent that, one should know the load and the minimum inflation, plus check it periodically. Some invest in pressure monitoring systems to help them. Some use a tire gauge.

I add a third safety measure, and I see from your other posts you have invested in an IR thermometer. At each stop, I walk the coach and toad checking tire temperatures with my hand. I am looking for a tire that is hotter than the rest which would be one's early indication of underinflation.

No, they are not made of crystal. And the world does not come to an end if you are off a few psi one way or the other. Besides, it would be comical to test an array of tire gauges at the pressures we run to see how they compare to each other.

Sorry for the long discourse.

Thanks Bikeboy! This is among the most rational answers I've seen on the forum in ages.

[mike_brez]

wolfe10 wrote:

Effy 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.

Never understood the 5-10 PSi over the chart thing I see on here all the time. Why? If the chart says at x weight adjust to Y PSI, why would you go over? 10 miles down the road once they heat up now you are way outside the parameters specifically outlined in the chart. I don't get it. Over inflated tires can be just as bad as underinflated. Why wouldn't you go by the chart?

Understanding what the tire charts represent explains it all. They give the MINIMUM PSI for a given weight. Said another way, if it weighs more, the chart moves you to a higher PSI.

To keep from over-complicating PSI, most of us take the minimum and add 5-10 PSI to account for: cold fronts (lower temperatures), that big shopping trip, extra guests, full tanks, etc.

This is exactly why I do what I do. Sometimes my kids come with us sometimes they don't. Sometimes we have four bikes hanging on the Thule rack and sometimes two and yes my wife can shop with the best of them. This is just what I do and has worked out fine for me.

[rgatijnet1]

The difference between automobile and truck tires, as opposed to RV tires, is that they are run usually well under the maximum chassis weight. Most RV's are loaded, and go down the highway 90% of the time, at the full maximum axle weight for the chassis. That is why it is recommended to weigh the coach.
Truck drivers that carry the maximum weight in their trailers probably check their tires more often also. A semi-trailer loaded with potato chips or other lighter than maximum load, are probably a little less critical of their tire pressure.
I check my tire pressures regularly because I know I am always close to, or slightly over the max weight, depending on my water tank levels.