ST Tire Life - Fiberglass RV


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Old 06-28-2012, 01:18 PM   #1
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ST Tire Life

I know this can has been kicked over and over but I stumbled onto something at the Discount Tire Direct web site. Buried into their FAQ regarding trailer tires, which in total is fairly interesting was this sentence.

Time:

  • Time and the elements weaken a trailer tire.
  • In approximately 3 years, roughly one third of the tire's strength is gone.
  • Three to five years is the projected life of a normal trailer tire.


That note about the tire's strength is really interesting. I just wonder if one could project how that relates to the load bearing capacity/and the operating speed of an ST tire. No wonder so many of these things are self destructing at a young age.

Based on the tire failure poll here on the forum (est) you see an almost 100 % increase in tire failures in the year 3 time period. If the Discount Tire info is correct, it is entirely possible that our ST tires deteriorate enough over their first two years life to be truly unworthy of trusting in that third year of use.
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Old 06-28-2012, 01:58 PM   #2
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Quote:
Originally Posted by MC1 View Post
I know this can has been kicked over and over but I stumbled onto something at the Discount Tire Direct web site. Buried into their FAQ regarding trailer tires, which in total is fairly interesting was this sentence.

Time:

  • Time and the elements weaken a trailer tire.
  • In approximately 3 years, roughly one third of the tire's strength is gone.
  • Three to five years is the projected life of a normal trailer tire.
That note about the tire's strength is really interesting. I just wonder if one could project how that relates to the load bearing capacity/and the operating speed of an ST tire. No wonder so many of these things are self destructing at a young age.

Based on the tire failure poll here on the forum (est) you see an almost 100 % increase in tire failures in the year 3 time period. If the Discount Tire info is correct, it is entirely possible that our ST tires deteriorate enough over their first two years life to be truly unworthy of trusting in that third year of use.
My OE Marathons went 4 years and 26000 miles and were removed with 40% tread. It's now been 4 years and 30000 miles on better Carlisle tires,
When they need replaced it will be with Carlisle's newest radial which has been improved once again with better compounds and greater UV resistance for better longevity. This discussion generally degenerates into citing the Logan's Run method of tire replacement... But two years with average mileage?...
If they've been on a good axle they should be fit for resale to someone who knows how to inspect a tire.
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Old 06-28-2012, 03:32 PM   #3
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Originally Posted by floyd View Post
If they've been on a good axle they should be fit for resale to someone who knows how to inspect a tire.
I think that's the problem - I had a pair of tires that looked just fine - that was until one day when they were two months short of their 4th birthday they decided to start to come apart.

The information that MC1 stumbled on is pretty well what I was told at the tire store as well. But they suggested the reason for it was due to the fact that trailers spend way more time parked than a car which results in much faster deterioration. Which leaves me wondering if you would see the same deterioration results of a regular tire vs a trailer tire if the car was parked as much as the average trailer.
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Old 06-28-2012, 03:42 PM   #4
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Most race cars spend nearly all their time parked, yet the tires seem to be good for speeds unimagined by most drivers and continue to do so for 5-7 years.

ST tires on the other hand are unreliable upon installation and then they get worse. They cannot even be used to travel at the speed limit.

The definition of a happy Marathon owner is one who got more than 10 miles from the tire store with his brand new ones before the first failure happened.
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Old 06-28-2012, 03:52 PM   #5
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Originally Posted by BCDave View Post
Most race cars spend nearly all their time parked, yet the tires seem to be good for speeds unimagined by most drivers and continue to do so for 5-7 years.

What type of race car are referring to Dave? The ones I spent part of my youth around rarely made it through a race without a tire change - in fact at least one complete tire change was always planned if not two depending on the length of the race.
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Old 06-28-2012, 04:20 PM   #6
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I'm a drag racer from WAY back. The slicks would sometimes be good for 2-3 years but fronts were often on the car for longer than I was ever associated with any one car. In the "pro" classes, a car can go thru a pair of slicks in a weekend (or even several in a day!), but "doorslammer" sportsman cars are generally cheaper to play with (and WAY more fun) than nearly any sport out there! In many classes, if you are using up more than one pair of slicks per year you are doing something wrong

Often the cars just got unloaded and parked in the back yard "til next year" with the occassional move into the shop for an update/refresh and then it gets pushed back outta the way back into the yard again, maybe with a cover on it.

The Camaro I drove last year was on its second pair of slicks in 3 years but still had the same fronts after 5. No idea if it has any tire changes now, as it was sold to a guy in California last fall, while the engine & trans are awaiting a new assignment, which I am told is likely to be a late-60's Nova.
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Old 06-28-2012, 07:01 PM   #7
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My thoughts on the ST tire debate previously shared on another forum:

Few things generate more passion than discussion of tires on the forums. Since I was not a tire expert I did a lot of research before making my decision on tires. This includes researching every related forum I could find and corresponding with different tire manufactures directly.



The above picture shows my M8008 Maxxis tires at 32,000 miles being replaced with a new set of M8008 tires. My old tires have traveled from Canada to Mexico in snow, mud, gravel and washboard roads without a failure. I saw no defects in my tires when I replaced them, in fact they look almost like the new ones.

At the time I acquired my trailer there were a lot of postings about tire failures on Casitas and other travel trailers.

The US manufacturers had outsourced trailer tires (ST) overseas and there were apparent startup quality problems.

At the same time, Casita and other trailer manufacturers were equipping their trailers with inadequate load rated tires on their trailers. Casita was offering ST205/75R-14, 6 ply, 1,760 lbs capacity ea.(or 3,520 total lbs) load range "C" tires, inadequate for loads experienced on the road.

The heavier SD model Casita trailers when loaded weigh up to 3,500 lbs. (Measurements at the Oregon Ralley)

Casita now offers 15" load range "D" Goodyear tires as an option that seem to be holding up well.

I contacted Maxxis Technical Support and asked them what was the best tire I could put on my 3,400 lb loaded Casita trailer. The response was the Maxxis M8008 ST tires, 225/75R/15. load range "E" tire. These 10 ply tires are rated to carry 2,830 lbs each at 80 psi. Maxxis ST tires are specifically designed for trailers.

Discount Tire has been the largest independent tire distributor since 1960, as such they should have some insight into tires for trailer use, here is what they say.

Why Use An "ST" Tire
*"ST" tires feature materials and construction to meet the higher load requirements and demands of trailering.
* The polyester cords are bigger than they would be for a comparable "P" or "LT" tire.
* The steel cords have a larger diameter and greater tensile strength to meet the additional load requirements.
* "ST" tire rubber compounds contain more chemicals to resist weather and ozone cracking
* Always inflate trailer tires to the maximum inflation indicated on the sidewall. (They say this twice to get your
attention. Anyone that tells you over inflation of trailer tires is the leading cause for failure is WRONG).

* In approximately three years, roughly one-third of the tire's strength is gone. (Another reason why you need a tire
with a load rating that greatly exceeds the weight of your trailer).
* Three to five years is the projected life of a normal trailer tire.(forget what you know about passenger tires, it does not apply to trailer tires).
* It is suggested that trailer tires be replaced after three to four years of service regardless of tread depth or tire appearance.
Trailer Tire Facts - Discount Tire

According to Mac Demere of 'Edmunds,' nearly every tire blowout occurs on a warm day, on a straight road, at highway speeds when a tire is under-inflated.

Tire Rack says:
"Your trailer is a follower, which often makes tire sidewall flexing a negative. Sidewall flexing on trailers, especially those with a high center of gravity (enclosed/travel trailers) or that carry heavy loads, is a primary cause of trailer sway. Typical passenger radial tires with flexible sidewalls can accentuate trailer sway problems. The stiffer sidewalls and higher operating pressures common with Special Trailer (ST) designated tires help reduce trailer sway.

Goodyear Tire Company says this:
"For trailer tires, inflating near the max pressure indicated on the tire sidewall is a good option for cooler running lower rolling resistance and load-carrying capacity. If the load the tire is carrying isn't near its capacity, lower-than-maximum psi can be used (see load and inflation tables for proper inflation) and this may give a slightly better ride, but never allow the tires to be under-inflated (lower than what the trailer manufacturer recommends)."

"Industry standards dictate that ST tires are restricted to a speed of 65 mph unless a different speed restriction is indicated on the tire sidewall. If speeds from 66 to 75 mph are used, the tire cold inflation pressure can be increased by 10 psi without any increase in load." (Same thing Maxxis told me, wheel pressure maximum rating must be considered if over inflating the tires to run at higher speed).

I don't ride in my trailer so a "slightly better ride" is not a consideration. I inflate my tires at near maximum, I want the cooler tire temp and maximum load carrying capability. With some 40,000 miles now on M8008 tires without any failures, I am completely satisfied and have zero worries about tire performance as I travel down the road.

Gary RV Forum Staff: Trailer tires seem to be prone to early failures. There are several potential reasons and the anecdotal reports we get are seldom detailed enough to make sound conclusions. Here are some of the major factors:

(1) Most trailers have barely adequate tires right from the factory. By that I mean that they are rated just high enough
for the axle GAWR, so that they are always running right at their outer limit of capacity. To make matters worse, trailer manufacturers have been skimping on the axle ratings as well, so that the axle itself is usually loaded right to the max in normal use. In my opinion this high level of stress causes trailer tires to fail far more often than passenger car cars, which typically have a substantial safety margin in carrying capacity.

(2) Trailer tires (and RVs tires in general) do not get regular use (exercise). Instead, they sit around getting stiff and flat on one side and the anti-aging chemicals in the rubber do not get spread around. Then they get taken out on the highway and run hard and hot on the highway, usually in hot summer weather. And sometimes on rugged roads too (campground access roads). This is the worst style of usage for a tire, according to tire manufacturers, and leads to a failure rate greater than average for all tires. Some people also feel that long exposure to sun (UV damage) and contact with the ground or concrete will also cause tire damage while it sits. I don't see any meaningful difference vs passengers cars, though, and they routinely last 4-5 years or more.

(3) As with many RVs, trailer tires are often underinflated for the load. Yeah, I know, YOU always check yours and never run under-inflated (and your dog never barks in the campground either), but weight checks by the RVSafety Foundation show that a substantial percentage of RVs have one or more tires under-inflated for the actual load. An under-inflated tire flexes more than it should and gets much hotter than when properly inflated. That greatly increases the likelihood of tread separation or sidewall failure, i.e. a "blow out".

It is my contention that most trailer tire problems are the result of using tires with inadequate load ratings for the trailer weight along with inadequate inflation to allow the tires to handle the load. Tire age, sun damage, and not moving the trailer for long periods in storage are also contributors to failures.
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Old 06-28-2012, 07:14 PM   #8
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Originally Posted by Carol H View Post
I think that's the problem - I had a pair of tires that looked just fine - that was until one day when they were two months short of their 4th birthday they decided to start to come apart.

The information that MC1 stumbled on is pretty well what I was told at the tire store as well. But they suggested the reason for it was due to the fact that trailers spend way more time parked than a car which results in much faster deterioration. Which leaves me wondering if you would see the same deterioration results of a regular tire vs a trailer tire if the car was parked as much as the average trailer.
Trailers with torsion axles are supposed to be stored with the axle at least nearly unloaded and ST tires are supposed to be stored unloaded and at reduced pressure. Mine are stored indoors on the trailer partially unloaded at full pressure, but they have seldom ever been stored for more than three months at any given time and even in storage, they get moved around.
I can't say if "looked just fine" would be the same to you as it would be to me, but every tire is subject to the possibility of sudden catastrophic failure from the first moment it is mounted and inflated.( Heck..i've even seen them fail in the process)
I take every (subjective) reasonable precaution and I have never had a flat or a blowout on a trailer tire, but it is still a possibility everytime I leave the driveway with trailer in tow. I just don't buy the "Logan's Run" approach.
It is said that "generalities are always false" and it is especially true when you consider the variety of construction and materials used to manufacture tires... Heck they still make some of them out of carbon steel!
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Old 06-28-2012, 07:20 PM   #9
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Quote:
Originally Posted by baron100 View Post
My thoughts on the ST tire debate previously shared on another forum:

Few things generate more passion than discussion of tires on the forums. Since I was not a tire expert I did a lot of research before making my decision on tires. This includes researching every related forum I could find and corresponding with different tire manufactures directly.



The above picture shows my M8008 Maxxis tires at 32,000 miles being replaced with a new set of M8008 tires. My old tires have traveled from Canada to Mexico in snow, mud, gravel and washboard roads without a failure. I saw no defects in my tires when I replaced them, in fact they look almost like the new ones.

At the time I acquired my trailer there were a lot of postings about tire failures on Casitas and other travel trailers.

The US manufacturers had outsourced trailer tires (ST) overseas and there were apparent startup quality problems.

At the same time, Casita and other trailer manufacturers were equipping their trailers with inadequate load rated tires on their trailers. Casita was offering ST205/75R-14, 6 ply, 1,760 lbs capacity ea.(or 3,520 total lbs) load range "C" tires, inadequate for loads experienced on the road.

The heavier SD model Casita trailers when loaded weigh up to 3,500 lbs. (Measurements at the Oregon Ralley)

Casita now offers 15" load range "D" Goodyear tires as an option that seem to be holding up well.

I contacted Maxxis Technical Support and asked them what was the best tire I could put on my 3,400 lb loaded Casita trailer. The response was the Maxxis M8008 ST tires, 225/75R/15. load range "E" tire. These 10 ply tires are rated to carry 2,830 lbs each at 80 psi. Maxxis ST tires are specifically designed for trailers.

Discount Tire has been the largest independent tire distributor since 1960, as such they should have some insight into tires for trailer use, here is what they say.

Why Use An "ST" Tire
*"ST" tires feature materials and construction to meet the higher load requirements and demands of trailering.
* The polyester cords are bigger than they would be for a comparable "P" or "LT" tire.
* The steel cords have a larger diameter and greater tensile strength to meet the additional load requirements.
* "ST" tire rubber compounds contain more chemicals to resist weather and ozone cracking
* Always inflate trailer tires to the maximum inflation indicated on the sidewall. (They say this twice to get your
attention. Anyone that tells you over inflation of trailer tires is the leading cause for failure is WRONG).
* In approximately three years, roughly one-third of the tire's strength is gone. (Another reason why you need a tire
with a load rating that greatly exceeds the weight of your trailer).
* Three to five years is the projected life of a normal trailer tire.(forget what you know about passenger tires, it does not apply to trailer tires).
* It is suggested that trailer tires be replaced after three to four years of service regardless of tread depth or tire appearance.
Trailer Tire Facts - Discount Tire

According to Mac Demere of 'Edmunds,' nearly every tire blowout occurs on a warm day, on a straight road, at highway speeds when a tire is under-inflated.

Tire Rack says:
"Your trailer is a follower, which often makes tire sidewall flexing a negative. Sidewall flexing on trailers, especially those with a high center of gravity (enclosed/travel trailers) or that carry heavy loads, is a primary cause of trailer sway. Typical passenger radial tires with flexible sidewalls can accentuate trailer sway problems. The stiffer sidewalls and higher operating pressures common with Special Trailer (ST) designated tires help reduce trailer sway.

Goodyear Tire Company says this:
"For trailer tires, inflating near the max pressure indicated on the tire sidewall is a good option for cooler running lower rolling resistance and load-carrying capacity. If the load the tire is carrying isn't near its capacity, lower-than-maximum psi can be used (see load and inflation tables for proper inflation) and this may give a slightly better ride, but never allow the tires to be under-inflated (lower than what the trailer manufacturer recommends)."

"Industry standards dictate that ST tires are restricted to a speed of 65 mph unless a different speed restriction is indicated on the tire sidewall. If speeds from 66 to 75 mph are used, the tire cold inflation pressure can be increased by 10 psi without any increase in load." (Same thing Maxxis told me, wheel pressure maximum rating must be considered if over inflating the tires to run at higher speed).

I don't ride in my trailer so a "slightly better ride" is not a consideration. I inflate my tires at near maximum, I want the cooler tire temp and maximum load carrying capability. With some 40,000 miles now on M8008 tires without any failures, I am completely satisfied and have zero worries about tire performance as I travel down the road.

Gary RV Forum Staff: Trailer tires seem to be prone to early failures. There are several potential reasons and the anecdotal reports we get are seldom detailed enough to make sound conclusions. Here are some of the major factors:

(1) Most trailers have barely adequate tires right from the factory. By that I mean that they are rated just high enough
for the axle GAWR, so that they are always running right at their outer limit of capacity. To make matters worse, trailer manufacturers have been skimping on the axle ratings as well, so that the axle itself is usually loaded right to the max in normal use. In my opinion this high level of stress causes trailer tires to fail far more often than passenger car cars, which typically have a substantial safety margin in carrying capacity.

(2) Trailer tires (and RVs tires in general) do not get regular use (exercise). Instead, they sit around getting stiff and flat on one side and the anti-aging chemicals in the rubber do not get spread around. Then they get taken out on the highway and run hard and hot on the highway, usually in hot summer weather. And sometimes on rugged roads too (campground access roads). This is the worst style of usage for a tire, according to tire manufacturers, and leads to a failure rate greater than average for all tires. Some people also feel that long exposure to sun (UV damage) and contact with the ground or concrete will also cause tire damage while it sits. I don't see any meaningful difference vs passengers cars, though, and they routinely last 4-5 years or more.

(3) As with many RVs, trailer tires are often underinflated for the load. Yeah, I know, YOU always check yours and never run under-inflated (and your dog never barks in the campground either), but weight checks by the RVSafety Foundation show that a substantial percentage of RVs have one or more tires under-inflated for the actual load. An under-inflated tire flexes more than it should and gets much hotter than when properly inflated. That greatly increases the likelihood of tread separation or sidewall failure, i.e. a "blow out".

It is my contention that most trailer tire problems are the result of using tires with inadequate load ratings for the trailer weight along with inadequate inflation to allow the tires to handle the load. Tire age, sun damage, and not moving the trailer for long periods in storage are also contributors to failures.
Great Post!
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Old 06-28-2012, 07:32 PM   #10
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To be honest I have never had an ST tire fail while on the road. As I mentioned above I did have to replace a set of ST tires this winter that where just short of their 4th birthday but it didnt actually fail while I was driving. I do keep the tires inflated to max and I had already done a lot of miles on that trip (over 3000) and one day having traveled a couple hundred miles on a fairly rough road when I stopped for gas it was noticed that one of the tires appeared to be separating in a tiny spot in the middle of the tread -went directly to a tire store who confirmed it and replaced both right away. Now I know that once an ST tire hits over 3 years of age I should start thinking about replacing them regardless of how good they may look on the outside to me.
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Old 06-28-2012, 07:37 PM   #11
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[QUOTE=floyd;318168]
I take every (subjective) reasonable precaution and I have never had a flat or a blowout on a trailer tire, but it is still a possibility everytime I leave the driveway with trailer in tow. I just don't buy the "Logan's Run" approach.
It is said that "generalities are always false" and it is especially true when you consider the variety of construction and materials used to manufacture tires... /QUOTE]

LOL Floyd what you say is very true! But the same can be said with car tires. Now thats a topic!
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Old 06-28-2012, 07:46 PM   #12
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After reading the above post concerning the Maxxis tires I was intrigued - anything has to be better than Badyear Marathons!

So I went to the Maxxis website and looked 'em up

They, too, cannot be towed at the speed limit

Oh well - back to the drawing board
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Old 06-28-2012, 07:54 PM   #13
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Originally Posted by BCDave View Post
After reading the above post concerning the Maxxis tires I was intrigued - anything has to be better than Badyear Marathons!

So I went to the Maxxis website and looked 'em up

They, too, cannot be towed at the speed limit

Oh well - back to the drawing board
Back to the drawing board ?

....okay......Kumho 857 or Hankook RA08.
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Old 06-28-2012, 08:01 PM   #14
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Originally Posted by BCDave View Post
After reading the above post concerning the Maxxis tires I was intrigued - anything has to be better than Badyear Marathons!

So I went to the Maxxis website and looked 'em up

They, too, cannot be towed at the speed limit

Oh well - back to the drawing board
All ST tires are labeled for 65MPH...
Bureaucrats always have your best interest at h...never mind!
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