Time really does fly!

[jsmith948]

In May of 2103, we replaced our Cougar's OE Towmax Load range 'D' tires with ST 225/75R/15E Maxxis after the DW discovered cracking/checking on the sidewall of one of the Towmax.
We have been very pleased with the Maxxis. However, having recently read on here that the load carrying capability of ST tires can degrade as much as 10% per annum, I thought I would run the numbers.

New(May 2013)-----------Load capacity = 2830#
May 2014------------------Load capacity = 2830-10% = 2547#
May 2015------------------Load capacity = 2547-10% = 2292#
May 2016------------------Load capacity = 2292-10% = 2063#

Our trailer is fitted with 4400# axles and the weight on the trailer axles usually scales at 8000#. Based on my math, the Maxxis tires are right at the minimum load capacity for the weight of our trailer.
My older brother scoffs at the idea of replacing 3 year old tires. He only recently replaced his OE Carlisles on his Forrest River TT after 12 years!
Now - My DB could fall into the proverbial 'barrel of poo' and come out with a diamond ring in his hand. If I fell into a barrel of diamonds, I would come out with poo on my hands! So, as much as I don't like spending the money, I'm leaning toward new tires before we make our planned 7000+ mile trip this summer. I e-mailed Maxxis for their take, but don't really expect to hear anything different.
Any comments? I have looked for the tire blog that CW has but have been unable to locate it. I know opinions will vary all over the map on this, but, I would really appreciate any comments/fact sources the members might offer. I realize tires are way cheaper than the damage they can cause.
(tx)

[notanlines]

Jack, just send him a message here and I'll bet he responds right away....

http://www.keystonerv.org/forums/member.php?u=1012

[JRTJH]

This is what Carlisle has to say: "3 to 5 years is the average life expectancy of a trailer tire, regardless of mileage." http://www.carlstargroup.com/cms_files/original/Trailer_Tires__Tips_Best_Practices.pdf

The West Marine website says much the same: "According to rubber industry research, trailer tires need to be replaced after 3-5 years of use, even though they usually appear to have plenty of tread left. Unlike your car’s tires, it isn’t miles of driving but oxidation of the rubber that wears out the tire. Mostly, a trailer tire sits in one spot for days or weeks at a time, and may travel only 10,000 miles (or sometimes a lot less) per year. UV radiation from sunlight and ozone from exhaust cause exterior damage to the sidewalls, and oxygen from pressurized air creates unseen damage deep inside."
http://www.westmarine.com/WestAdvisor/Trailer-Tire-Basics

RW Trailer Parts website says much the same: "Trailer tires are made NOT to wear out! “ST” tires (for trailers) contain chemicals in the rubber compounds to resist weather and sun damage. The most common reason for tire failure is underinflation. Trailer tires are designed to be used only at their MAXIMUM inflation. Trailer tires take a much higher psi than automotive tires. The stiffer walls are designed to withstand the shocks of road hazards even though the trailer suspension is inferior to an automobile’s. A trailer tire’s lifespan is expected to be anywhere from 5,000 – 12,000 miles.

Trailer tires are designed to be replaced every 3-5 years. Time and elements reduce a tire’s weight rating by about 1/3rd in approximately three years. It is suggested that you replace trailer tires every 5 years regardless of visual appearance." https://rwtrailerparts.wordpress.com/2012/03/27/interesting-trailer-tire-facts/

I'm replacing the tires on my 2014 Cougar this spring before the first trip. They are almost 3 years old and I don't want to risk any damage "just in case"...

With your "diamond barrel luck" I don't know that you'd have the good fortune to make it to 12 years on a set of ST tires, even though your brother was that lucky......

[jsmith948]

John - thanks for the response. The Maxxis have 8500 miles on the clock - about midway between the 5,000 to 12,000 average you quoted. So, I will do my part to keep the tire industry solvent and spring for a new set. Besides, the last time I got lucky was when I married my DW 48+ years ago!:)

[jsmith948]

Contacted Maxxis regarding the rate of load capacity degradation on their ST tires. Thought I would share their response:

I sent this message to Maxxis:

Purchased ST 225/75/15E Maxxis in May of 2013.
Have read that ST tires lose 10% of their load carrying capacity per year due to degradation of the rubber compounds. Based on this calculation, I would need to replace these tires after only 3 years of service.
Is this accurate? What do the Maxxis engineers calculate as the annual percentage of load capacity reduction ?

This is their response:

According to Maxxis Engineer's, a tire's load carrying capacity is from tire pressure. So long as a tire can take the same tire pressure without damage, the tire will be able to carry the same load as a new tire regardless of age.

Your Maxxis Support Team

I highlighted the key phease. I wanted a response from engineering and I think the lawyers answered:p

[JRTJH]

Contacted Maxxis regarding the rate of load capacity degradation on their ST tires. Thought I would share their response:

I sent this message to Maxxis:

Purchased ST 225/75/15E Maxxis in May of 2013.
Have read that ST tires lose 10% of their load carrying capacity per year due to degradation of the rubber compounds. Based on this calculation, I would need to replace these tires after only 3 years of service.
Is this accurate? What do the Maxxis engineers calculate as the annual percentage of load capacity reduction ?

This is their response:

According to Maxxis Engineer's, a tire's load carrying capacity is from tire pressure. So long as a tire can take the same tire pressure without damage, the tire will be able to carry the same load as a new tire regardless of age.

Your Maxxis Support Team

I highlighted the key phease. I wanted a response from engineering and I think the lawyers answered:p

I agree with your thoughts, this isn't an "engineering comment"....

Here's the "official Carlisle Tire Company comment":

It is estimated that in approximately three years, roughly
one-third of a tire's strength is gone.
– After three years, depending upon storage and conditions of
usage, consider replacing trailer tires even if they have tread
depth remaining.
– After five years, trailer tires should be replaced in all cases.

It's found on the bottom of the 3rd page: http://www.carlstargroup.com/cms_files/original/Trailer_Tires__Tips_Best_Practices.pdf

So, I guess it's more a matter of "who you believe" and "what you believe"....

Wouldn't it be great if all the manufacturers were at least "consistent" ..... LOL

[jsmith948]

Well, having read numerous posts/opinions regarding the longevity of ST tires,
we have replaced our Maxxis tires after 3 1/2 years. Having had zero issues with the Maxxis, we intended to replace them with another set, but, we were having a difficult time finding a set of LRE's. Finally found some at Discount Tire (they could order them in) but the price had gone up a good bit from 3 years ago. After reading posts here, doing some online research and watching some videos showing the construction of Carlisle's 'new generation' st tire, we decided to go with the new Trail RH Carlisle. Saved about $250 for a set of 4.
BTW, I noticed that the sidewalls on the new tires seem to be a bit stiffer than on the Maxxis and there is less 'sidewall bulge'.

[canesfan]

Well, having read numerous posts/opinions regarding the longevity of ST tires,
we have replaced our Maxxis tires after 3 1/2 years. Having had zero issues with the Maxxis, we intended to replace them with another set, but, we were having a difficult time finding a set of LRE's. Finally found some at Discount Tire (they could order them in) but the price had gone up a good bit from 3 years ago. After reading posts here, doing some online research and watching some videos showing the construction of Carlisle's 'new generation' st tire, we decided to go with the new Trail RH Carlisle. Saved about $250 for a set of 4.
BTW, I noticed that the sidewalls on the new tires seem to be a bit stiffer than on the Maxxis and there is less 'sidewall bulge'.

Let us know how you like them. They are on my list as my OEM tires are going on 2-1/2 years and even though they look fine and only have a couple thousand miles on them at most I don't trust them.

[Desert185]

I'm a Maxxis ST fan, but have mounted the Carlisle Radial Trail RH's LRD's on my carhauler and enclosed utility trailer as test subjects. I'll be curious to see how the "heavies" do when its time for a tire change on my SRX.

I also see that Carlisle makes a 235/85-16 LRF. I'm going to research my wheels to see if they're PSI compatible with the higher load rating. Having the extra margin for those heavier times on the way to a dry camping spot with water, gas, etc. might be a good option.

[CWtheMan]

Most of the information on ST tire life found on the internet is from Carlisle Tire. A lot of that is older information and is no longer relevant.

For more valid information about a specific brand the brand manufacturer should be contacted. Only they know what materials were used in their rubber compounding processes.

Maxxis has long said their radial trailer tires are normally good for 20000 miles+.

Tire aging for trailer tires has no solid information. Owner “A” may only use 85% of the maximum load capacity and have an average storage time of 7 months a year. Owner “B” may use more than 95% of the maximum load capacity and be in storage 3 month of the year. So, possibly the 3-5 year range could fit both of those situations. Personally I change my tires every three years or whenever they come out of storage with over 3 years on them. I use the date of purchase. My tires are always using 75 - 85% of their load capacity. In storage I insure the trailer is level and the tires are always properly inflated and on wooden blocks.

It’s hard to bring yourself to change tires that look just like new. Experience has taught me it’s the best thing to do regardless of mileage or looks. The good part is they will sell. In our neighborhood I can just put a sign on my old tires, set them out in the yard and they are normally gone on the first day. Those yard workers just love them for their trailers.

[fla-gypsy]

Since Maxxis warrants their tire for 5 years I have to believe they are confident in achieving that at a percentage that would be advantageous to them monetarily. They are certainly the best ST tires I have ever owned. The "new" Carlisle Radial Trail RH (only) I would consider after a couple more years of experience from those using them since they have not been available very long.