Been following an RV forum thread on tire age and have been trying to explain why there is no strict guideline for exactly when a tire should be replaced. I summed up my position...
The general guidelines for motorhomes is to have the tire inspected
starting at about 5 years and to replace at 10 years no matter what the
inspection indicates. Due to the Interply Shear effects on belt durability, trailer tires need to be closely inspected after a couple of years and it appears that 5 years may be the max life for most applications.
I do understand that people would like a
nice clear precise answer but the problem is that with load, speed and
temperatures all having an impact on the life of a tire it is impossible
to give a precise time of when to replace a tire.
In today's
society no company can give a specific answer to the question as they
would be sued if a tire failed before the "end of life" time and they
would be sued if the tire lasted past the "end of life" time. We are
talking about probability.
You have a sticker on your RV telling
you the inflation to use based on an estimate of how much "stuff" you
will be carrying. Federal Regulations say the tire load capacity at the
specified inflation must be able to support the load rating of the axle.
This assumes an exact 50/50 side-to-side load split all the time. It
also assumes you do not put more or less load in your RV than what would
result in each axle being exactly at GAWR. Many have learned of the
importance of getting the actual load on each tire.
Maybe it would help if we thought about tread depth instead of age.
Exactly
how much tread can be worn off before a tire becomes "unsafe'. Most
states say 2/32" for passenger car tires but does that mean the tire with
3/32" tread will always perform equally to a tire with 10/32"? Of course not. As the tread wears the wet traction capability goes down. Do you
always wait till each tire gets to 2/32" before replacing it? If not,
why not?
Conversely the dry traction can go up as tread depth goes down, so there is a trade-off. I dare say that if you live is an area with lots of rain or even snow, you probably change tires before they are that worn. However, if you live in the dry Southwest you may be tempted to run less than 2/32" tread as you have seldom if ever have wet traction problems.
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Retired Tire Engineer here! (Roger knows me via the internet - We've talked many times)
ReplyDeleteAllow me to reiterate what Roger says here. Because it is so highly variable, no one can absolutely determine when a tire is too old. It is clear that 10 years is a good upper limit, but in some places (like Phoenix!) the limit is about 6 years.
Further, severe cracks are a good indicator that a tire should be removed - but a lack of cracks does not indicate a tire is good. That's because some tire manufacturers use types rubber that are resistant to cracking - but that only means you can't using cracking as a way to determine how good the rubber is.
I just replaced my tires on a 2008 Monaco with only 33,000 miles. I was at the factory service center in Decatur, In. for service and was told by them that after five years if there is accident due to tire failure that most insurance companis will not cover the damage or claim (They said that the first thing the insurance adjuster looks at is the tire code for age). I went to the Michelin dealer and put on 6 new ones and they told me the same thing. Is this true or can you run them longer then five year without worry?
Deletegolfdlux@aol.com
Richard, I have not seen such a statement in writing but you should ask your insurance agent not the RV store. Can you give me a contact at Monico? My email is under picture/video on right.
DeleteI can see an insurance company wanting to use about whatever excuse they can for not making a payment but would challenge an adjuster on their tire forensic capabilities or training. The mode and cause of failure might also have an affect on if you are covered or not. Read your insurance policy
Good article. We have a fifth wheel that we have weighed and know we are within our weight limit and the tires. Since having a tread separation on one tire back in 2014 due to old tires, we religiously have the tires inspected at the start of every season - spin test too. One tire area, two years in a row showed wear and the start of separation and at the advice of our RV tech, we had our FW's alignment checked. Sure enough it was off. Tires still get inspected and are good, but they are now 4.5 years old. They again will be inspected in the spring. If they are good to go should be do just that and go with the recommendation of the tire shop, which has a good reputation in our area?
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