"The tire is defective" More information

 I hear that statement quite often and will admit it is a bit of a "hot button" for me. For a good part of my 40 years as a tire design engineer I was tasked with doing Forensic level tire inspections and issuing "white paper" engineering summaries of the findings of the results of my inspection of tires that had failed. My inspection was not simply looking at the tire and saying "Yup it failed". I was expected to learn and identify the reason, the Root Cause for the failure, and to issue a report to management or even the auto company engineers. In a number of cases the report could be simple such as: "The tire suffered a belt separation at x thousand miles. The separation initiated between the two steel belts on the serial side and progressed until the tire failed. The bead area showed signs of under-inflation/overload."    or    The tire suffered a "Run Low Flex Failure which resulted in the melting of the polyester body cord as seen here.

It would never be acceptable for me to say "The tire failed so it obviously had a defect".

 I gave a short list of examples in my post of Sept 20, 2015. Improvements can not be made in tire production or in the manufacturing of any product if you only say "There was some Defect" for without knowing and clearly identifying the actual defect there is no way to know what material or process needs to be changed or improved to make the product better.

While simply saying the tire had a "defect" means you can't be sure that simply replacing the tire with a new one or even a new tire from a different manufacturer will prevent a re-occurrence of another similar failure.

Tire failures come from a number of different Root Causes. Some have nothing to do with the tire itself. These can include wheels that are porous like this one,

other wheels can develop cracks so they leak air, or are even the wrong size as seen here. I have previously covered the variety of "failures" that involve leaking valves.  Many failures are from external causes as seen in these examples. 

Now some may feel that because I worked in the tire industry I always want to blame the consumer but this is not the case. In fact I am personally responsible for one recall of over 8,000 tires based on my inspection and research that identified the root cause for the failure was a tire plant manufacturing error due to improper identification tag on a pallet of a specific rubber compound. Others had already seen the tires and decided they were "defective" but they stopped there and did not make the effort needed to properly identify exactly what the "defect" was.

While I understand that consumers really are only interested in getting back on the road. But if the reason for the failure was not something in the tire you can end up with another tire failure in your future.  If you have a failure and really care about the facts I may be able to help. First you need to keep the tire if possible. Get good overall picture IN FULL SUN LIGHT, Also some close-up pictures, Close enough that you have no more than about 12" of the tire in each shot.. Email me the pictures and I will be happy to work with you so we might learn the real cause. 

##RVT975

Valve stem extender potential problems

Sometimes my wife accuses me of being too negative because I seem to always come up with something negative about almost any topic. I really don't consider it negative when I see there might be a way to make something or a situation better.

I guess it's in my DNA to never be satisfied and always want things to be better, easier, safer or more durable.

The simple act of checking tire air pressure is an example.

 Each time you use a hand gauge to check air (morning of every travel day) you are pushing on the valve stem. If you have a standard short (less than 2") valve stem, no problem, BUT for dual tire positions as seen on almost all Class-A and Class-C RV motorhomes there are either valve stems that have a bend in them or there are  extenders  of some type. Pushing on a bent or angled stem will place a torque on the stem mount in the wheel. This can lead to eventual degradation of the rubber seal between the wheel and the stem.  Here is what happened a few years ago to the tire of a friend of mine. He was not running a TPMS so got no warning that the valve stem developed a leak at the rubber gasket between the wheel and the stem.

 

 The tire lost air and the steel body cords fatigued due to over-flexing of the sidewall which resulted in the sidewall "blowing out". Initially he thought it might be a "defective tire" but when inflating the new tire it was discovered that the valve stem no longer had a solid rubber gasket at the wheel. So obviously this was not a "defective tire" as any tire can fail if you do not keep the air in it. Soon after this he installed a TPMS.

 If you have some type of extenders, flexible hose or hard line, you might end up moving or bending re even loosening the extender if it isn't supported when you push a gauge or air chuck on the outer end.

One advantage of running TPMS that few people consider is that the TPMS gives you a pressure check each morning, as well as continuous as you drive down the road so this eliminates the need to push on the stem or extender.

TPMS eliminates this torque force on the valve stem mount along with saving you time to go out, get down on your knees, remove the metal valve cap, push on the stem and get a reading. Lots of fun if it is cold or raining.

 

I prefer to just turn on my TPMS in the morning and after my cup of coffee look at the TPM monitor and in a minute or two know the state of inflation for every tire.

 

No Muss or Fuss and the additional benefit of no torquing the valve stem mount. 

##RVT969

 

Are your tires "Defective"? (updated post from Nov 2018)

People making the claim that their tires were somehow "Defective" is an all too often occurrence on various RV forums. I even hear this complaint at my RV tire seminars. I do note that when there are tire problems, including actual "failure" it's common for some to say "My xxx brand tires failed, I will never buy xxx tires again".

It's important that we have a mutual understanding of what is meant by tire "failure". For some, this means the tire simply came apart. The term "failure" could also be applied to a snow tire that didn't provide enough traction to prevent getting stuck on slick ice. To a driver of a race car, it might mean that the cornering on one specification tire wasn't as good as with a different specification. It could even mean the dry slick tread pattern failed to provide enough traction when it started to rain during the race.

Well sorry to tell you but there is no such thing as "Fail-Proof" tire. This was even said, under oath by DOT spokesperson during the Ford Explorer rollover fiasco of 2000.

Even the new "run-flat" tires available on some expensive cars can "fail" if driven too fast or too far when "flat".

Today's tires are amazingly robust. Even when they are made in some country other than the US. I am sure that many of us remember how bad "Made In Japan" was considered when we were growing up, but just think of the quality perception is today of cars made or designed in Japan.  As I pointed out in this blog previously it is important that the tires you are using are appropriate for your ACTUAL loads and usage. If you have a heavy trailer application and both the tire type and the size was wrong and the tread pattern was wrong. for the application. Why would this be the tire's fault?

If you put a truck tire with a heavy off-road mud traction tread design on the front of your 40' DP and had loud noise and vibration and the harsh ride would that be the tire's responsibility?
Would simply changing tire brands from say Bridgestone to Michelin solve the problems? No of course not.
From my experiences as a tire engineer, I can tell you that I can probably "fail" any tire in under an hour and under 50 miles if you let me set the conditions.

A tire is just a tool you use to get a job done. If you don't select the correct tool that is appropriate for the job you want to be done why is it the fault of the tool manufacturer? Think of the absolute best tool company. Now select one of their flat blade screwdrivers. OK now start using it as a chisel and pound on it as you try and cut through some rusty bolts. After cutting through a few bolts would you blame SK or MAC or  Snap-On or ???? if the point of the screwdriver is dented and chipped?

All too often tire selection seems to consider price as the number one concern. This observation is certainly supported by almost every post that asks for tire suggestions from RV owners. Sometimes it seems as if the price might also be the only consideration for some RV assemblers. Now I would be the last to offer that simply having a higher price doesn't automatically make any given tire "better" and I am not suggesting that price should not be considered.

For some, any tire "failure" is considered proof that it was somehow "defective" even is the tire was

We need to smarter consumers when it comes to tires if we want to avoid ending up with tires we consider "Defective". To me, a "defect" would mean there is an identifiable condition, in the tire when new, that would prevent the tire from performing as expected for the stated life of the tire "when applied and used properly for it's intended purpose".
This means we should not expect a tire to run overloaded or underinflated or at excessive speed for years at a time.

The various RV owners' manuals I have seen, include warnings and advice on load, inflation speed, and tire life. Have you read that information? Do you follow the recommendations? If you don't and the tire "failed" do you accept responsibility or do you simply claim the tire was somehow "defective"?

##RVT929