Francesca Knowles wrote: Per mfr's recommendations for age of tires:
It's too bad the U.S.A. doesn't have a Rubber Manufacturers Association like the Brits do. These are the people that supply the material from which tires are MADE- not makers of the tire itself. Presumably they'd know what they're talking about in terms of the makeup up of the finished product.
According to Tire Rack's Tire Tech site(not Capriracer's private blog- the other one) these folks issued the following warning in 2001:
Tire Rack Tire Tech wrote: The British Rubber Manufacturers Association (BRMA) recommended practice issued June, 2001, states "BRMA members strongly recommend that unused tyres should not be put into service if they are over six years old and that all tyres should be replaced ten years from the date of their manufacture."
I actually think that even if not "advertised", most American companies follow the same guidelines, at least when ASKED about the subject. This may be partly due to raised public awareness after ABC aired that 2008 video on the subject of overage tires being sold all over the country.
THAT was a public relations problem, and the industry has definitely adjusted....
There is an RMA in the US. One of the main reasons it will be difficult if not impossible for any tire company to come out with a hard number is the lawyers in the US. The moment one company states "x" years there will be thousands of lawsutes from people who bought tires with certain expectations of having "y" numbers of years service but now can't so they want a 100% refund.
The other reason is competition. Imagine for a moment that Michelin said 6 years, Bridgestone said 7 years and Goodyear said 66 months. Now since most buy tires based on cost so you take the price and divide by the number of years to make your buying decision. Do you want to try and be competative in that market?
In the US it is against the law for the tire companies to discuss and agree on a max tire age so no one wants to be first because the competators will simply go a few months longer and you will end up out of business. You cannot change to match the competition because that will result in millions of dollars of inventory being worthless.
Then what happens if A. you wear your tires out before the age limit? You will sue for a refund. B. you fail to properly inflate your tire and it fails before the age limit? The tire company now has to prove itself innocent and that the tire was not properly maintained. C. You take care of your tires, don't drive much and they still have 25% tead left when the clock runs out. Now if they fail for any reason you are responsible for all damage or for the accident etc because you didn't change the tires at the age limit. Are you prepared for someone to tell you that you have to replace your tires when you think they are OK?
On the engineering side the facts are that if you spend all your time in Ohio your tires will "age" at about half the rate of what you would see if you spent all your time in Florida. So now how would you monitor where the owner spent their time?
The other reality is that England is a bit smaller than Michigan so the temperature range (aging rate) is significantly more uniform than in the US. Read my post on Tire Covers and at the end you can see a comment on different aging rates based on if you use covers or not.
In closing, DOT has been working for over 10 years trying to develop a simple, repeatable, aging test so they could include it in the regulations. So far, even with the support of the tire industry they have not found a test that takes even most of the variables into consideration never mind all the variables and the lawyers will sue if you don't consider all the possibilities.
You can learn more if you visit my tire blog RVTireSafety
In my opinion as a QS9000 and ISO/TS 16949 Quality auditor the word "Quality" does not appear to be in the RV industry dictionary.
It doesn't matter what the composition of the rubber is. What matters is how to express the aging thing in a way that is meaningful - in a way that Mr. Joe Average can know what to do. Unfortunately, this doesn't seem possible.
And what I was aiming at is also part of a tire's final composition.
Many of the ST tire manufacturers boast the addition of ozone protection chemicals in their ST tires. Are you saying those chemicals are from an industry wide standard and in no way aid or hinder tire aging?
FastEagle wrote: And what I was aiming at is also part of a tire's final composition.
Many of the ST tire manufacturers boast the addition of ozone protection chemicals in their ST tires. Are you saying those chemicals are from an industry wide standard and in no way aid or hinder tire aging?
FastEagle
No. What I was aiming at was that it only matters how the age limit is expressed so people can use it.
It doesn't matter what the composition of the rubber is. What matters is how to express the aging thing in a way that is meaningful - in a way that Mr. Joe Average can know what to do. Unfortunately, this doesn't seem possible.
And what I was aiming at is also part of a tire's final composition.
Many of the ST tire manufacturers boast the addition of ozone protection chemicals in their ST tires. Are you saying those chemicals are from an industry wide standard and in no way aid or hinder tire aging?
FastEagle
Tire performance is based on test results on standard, repeatable tests not on specifice chemical composition of a tire.
The best examples are seen in the UTQG rating system used on passenger tires. There are standard tests used to arive at the UTQG traction rating levels and temperature rating.
Marketing claims that Company A uses "more anti-ozone chemicals" can be true but are relatively meaningless as some rubber compounds are more naturably resistant to Ozone attack than others so would need less additives to achieve equal performance. "More" than what tire? The ones they make for wheel barrows or the ones made for passenger tires?
You also are confusing the relationship between external visible sidewall cracking and the remainimg structural integrity of the internal components. In general more cracking is an indicator of the tires usage and exposure to heat, UV & O3 but is not absolute.
Think for a moment of Blood Pressure. Is there a specific number that if exceeded means you will definately have a heart attack?
Tires are organic as I pointed out in my post. Organics are very complex and not as easy to control or measure as the Aluminum and Titanium used in fighter aircraft. You know a lot more about aircraft than I do but I don't think you can say there is an age in months when an airplane is no longer safe to fly.
You know a lot more about aircraft than I do but I don't think you can say there is an age in months when an airplane is no longer safe to fly.
In this huge military aircraft graveyard in Arizona most of the aircraft aged out and we knew when they were going to do it. But, the materials that age out are much more predictable than DOT certified tires. (LOL)!
When a tire manufacturer is mixing up a lot of different compounds for building tires and those mixtures are, for the most part, confidentially known only to the builders, then they should be able to put a ball park figure on how long they will last (age wise). Michelin will not put an absolute figure on it but their most often published number is 10 years.
The six year number for shelf life of new, unmounted tires is not firm, but is most often mentioned.
The ST tire manufacturers are pretty close to unanimous on predicting a 3-5 year life expectancy for those issues. Where did that come from?
It’s a big country and the aging issue cannot be solved for numerous reasons. Maybe they should start by setting geographical regions and working from there.
FastEagle
* This post was
edited 04/02/12 11:56pm by FastEagle *
You also are confusing the relationship between external visible sidewall cracking and the remainimg structural integrity of the internal components.
Common Tireman, I'm not confusing that any more than I would confuse the function of expander tube brakes with disc brakes.
We are talking tires here. Try and analyze what I said and what impact the unknown has on the subject. When something is injected to prevent something it often causes some side effects. Could the injection of ozone inhibitors designed to offset early tire cracking have a side effect on the same tires aging? That’s all I was writing about. I know there is a very low probability of any positive answers. It’s a discussion forum about tires. Does the ST tire suffer more from these injections than other tire designs? Would it help to explain the ST tires 3-5 year life expectancy?
I wonder what happens to such tire additives when they set unexercised for five or six months in the desert states during the summer months? Cracking on the top half of the tires and nice smooth sides on the lower half?
Thank you for taking the time to explain the complexity of what is thought to be a simple question about tire age. It is much appreciated.
The manufactures of ST tires sort of hint to a possible life in their warranty. I have not seen every warranty but it seems that 5 years is found often as a tire warranty. Some slightly more some less. Weather checking seems to come up as 4 years or is not mentioned but the warranty stops at 5 years.
FE found this link for me that I could not find. On page 14 it states 1/16" (2/32") is the max depth of a side wall crack and then it needs to be replaced. This is the 1st I myself have seen a rating. It did not mentioned thread cracks with is what showed up in my last 2 sets of Maxxis ST radials at year 4.5
FastEagle wrote:
JBarca wrote:
Ex, Can you find the warranty on line? I look today and could not find it that I knew for sure it was for ST trailer tires. I wanted to see what they say about "weather checking". Some tire companies mention it and some do not.
While we do not yet have a simple answer to when a trailer tires should be replaced, we at least understand the situation better.
For me and towing mainly in Ohio, it appears the 5 year thought is about the expected life. If you get 6 or 7 years it may be luck. The damage to the camper from a blow out can be often times be worse then tire which you need to buy anyway. Since I deal with machinery for a living and believe in Preventive Maintenance programs for wear components, why shouldn't a tire be any different then a brake lining, oil change or any other consumable wear parts. Replace them before the fail.
Thanks again.
John
John & Cindy
2005 Ford F350 Super Duty, 4x4; 6.8L V10 with 4.10
CC, SB, Lariat & FX4 package
21,000 GCWR, 11,000 GVWR
Ford Tow Command
1,700# Reese HP hitch & HP Dual Cam
2 1/2" Towbeast Receiver
2004 Sunline Solaris T310SR
(I wish we were camping!)
You also are confusing the relationship between external visible sidewall cracking and the remainimg structural integrity of the internal components.
Common Tireman, I'm not confusing that any more than I would confuse the function of expander tube brakes with disc brakes.
We are talking tires here. Try and analyze what I said and what impact the unknown has on the subject. When something is injected to prevent something it often causes some side effects. Could the injection of ozone inhibitors designed to offset early tire cracking have a side effect on the same tires aging? That’s all I was writing about. I know there is a very low probability of any positive answers. It’s a discussion forum about tires. Does the ST tire suffer more from these injections than other tire designs? Would it help to explain the ST tires 3-5 year life expectancy?
I wonder what happens to such tire additives when they set unexercised for five or six months in the desert states during the summer months? Cracking on the top half of the tires and nice smooth sides on the lower half?
FastEagle
What is on paper and what happens in real life will very a lot. In real life use you should have it pretty well figured out. Why don't you lay out the time line of your tire use. Maybe others will learn from it, and to not run a ST beyond is warranty.
I tried to find the warranty period for the GY Marathon's. Tire Rack lists it at 6 years, however I think I have seen you post three years. I could not find anything on GY web site other than the G670 warranty at 6 years, and I think that Tire Rack was confusing that.
At any rate give that a failed tire can cause up to 4 or 5 thousand in damage to a trailer, then running it pass warranty is not wise. Good Year excludes consequential damages in their warranty, however they have been willingly paying it. Does Tow Max pay for damages to one's trailer?
A good table would be the tire make, warranty periods, coverage's and track record.
Chris
My Rig
2001.5 2500 STD CAB AUTO SLT 4x4, CTD 4:10's, Bomb'd to Tow
2005 Cardinal 29WBLX.
It’s a big country and the aging issue cannot be solved for numerous reasons. Maybe they should start by setting geographical regions and working from there.
FastEagle
Geographical regions sounds reasonable till you have to ask how fine of a measure do you want to consider. As I pointed out in my blog the "aging" process is just chemistry. The rate of change is not linear so it gets even more complex.
I have done extensive research on the "rate of aging" and will give but one example.
When you say Arizona is hot, people generally think of the high numbers we hear about from Phoenix but the reality is that there are large portions of Arizona that are not at all like Phoenix. In fact Flagstaff is colder than Cleveland, Ohio so tires actually "age" faster in Cleveland than Flagstaff if you were to spend 100% of your time in one location or the other and we were considering the heat related history only. I don't have the figures with me but tires in Phoenix 100% of the time "age" about 6 to 8 times as fast as those in Flagstaff as I recall.
The owner has a number of factors in their direct control such as load, speed, inflation, and sun exposure, but to exercise that "control" means having the knowledge and then taking action.
It is well known that getting your RV weighed and confirming you are not overloading or underinflating your tires is good thing to do so why do more that 55% of RV owners run overloaded when they have been told not to?
I have shown the effects in my blog of not having white tire covers when parked. So I have provided the data and knowledge that you should use white covers but just how many people have gone out and bought and started to use covers? I would guess fewer than 15% have or use white covers. Some even make things worse by using black cover because they like the looks.
So looking at my numbers how would you as a tire company give an age limit on an RV owner who spends months at a time parked with one side of the RV South facing without tire covers but is running light load so has a 25% reserve when running the 10,000 miles a year he travels at 55 mph vs another RV owner who always covers his tires but runs 5% overloaded and at 70 mph for his 10,000 miles. Oh ya one lives in Mobile AL and the other in Prescott AZ.
People here in the US would never accept the restrictions or follow the regulations that would need to be imposed to have meaningful tire age limits. We can't even get them to follow the speed rating and load capability guidelines and the mere mention of a Government regulation brings some to the point of violence.
* This post was
edited 04/03/12 08:26am by Tireman9 *
You also are confusing the relationship between external visible sidewall cracking and the remainimg structural integrity of the internal components.
Common Tireman, I'm not confusing that any more than I would confuse the function of expander tube brakes with disc brakes.
We are talking tires here. Try and analyze what I said and what impact the unknown has on the subject. When something is injected to prevent something it often causes some side effects. Could the injection of ozone inhibitors designed to offset early tire cracking have a side effect on the same tires aging? That’s all I was writing about. I know there is a very low probability of any positive answers. It’s a discussion forum about tires. Does the ST tire suffer more from these injections than other tire designs? Would it help to explain the ST tires 3-5 year life expectancy?
I wonder what happens to such tire additives when they set unexercised for five or six months in the desert states during the summer months? Cracking on the top half of the tires and nice smooth sides on the lower half?
FastEagle
The anti ozone chemicals are mixed into the sidewall compound and to a lesser extent into the tread compound as those are the components exposed to Ozone. The compounds that are of primary concern for long term durability are those directly around the steel belts and at the ends of the belts. These are internal compounds and do not need the same protection from external Ozone.
So when I said "confusing" I may not have used the best word.
Sidewall cracking will get worse with time and heat. Belt compound rubber will loose its strength with time and temperature (remember the non linear relationship).
My point was that we are using a feature (cracking) of one component to try and predict the properties of a different component. While both see heat of operation and both see heat due to different ambients the external compounds also are affected by Ozone, UV, car wash chemicals and abrasion. The relationship is not exact.
I believe flight hours are one of the primary measures of the life of aircraft and if hours were the only unit you could record you would come up with some number and apply statistics to arrive at a confidence level that the aircraft should or should not be ok to fly. This works till you run into an unusual situation as seen with Aloha Airlines when the side of the fuselage blew out.
I do not believe the ST tires suffer more from the inclusion in anti-oxidants in their sidewall rubber. (I have no knowledge of and do not believe that all ST tire sidewalls have more AO than any other tires.
I do believe that ST tires suffer from abnormal side loading due to tandem axles and to higher loading than they can tolerate at the speeds they are operated at, compounded with demands that they be lower cost than many other tires. Just as TPMS were mandated on cars because drivers refused to check their tires so a good portion were driving at 20% to 40% low I would like to see all RVs have TPMS.
I would also like to see metal valves on all RVs. Rubber valves are rated 65 psi max cold but most RVs seem to come with low cost rubber valves even when the spec is 65 psi for zero reserve. How about speed limiters on the TV when the RV is hooked up?
Sorry got off topic but the answer is not as simple as many would like.
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