Trailer Tires Explained

SilverRhino

Well-known member
Found this thread on another web site ...... thought it was interesting.

Trailer Tires Explained<!-- google_ad_section_end -->
<HR style="BACKGROUND-COLOR: #a3a4a6; COLOR: #a3a4a6" SIZE=1><!-- / icon and title --><!-- message --><!-- google_ad_section_start -->I copied and pasted this portion of a post by Mike Mitchell, NuWa (HitchHiker) CEO in a discussion regarding trailer tires on the NuWa Owner's Forum.
++++++++++++++++++++++++++++++++++++++++++++++++

"Read the following and learn from this RV.net fellows research. MIKE

As we banter about regarding tire types and loading, I believe that we are finally starting to understand a few important things.

I have asked many times for someone to explain how a ST tire can be rated to carry more weight than a LT tire in a similar size, without a good answer.

The answer lies in what is called reserve capacity. To quote from Trailer Parts Superstore and this same statement exist on just about every tire site:

HEAVY DUTY 'LT' TRUCK / TRAILER TIRES
'LT' signifies the tire is a "Light Truck/Trailer" series that can be used on trailers that are capable of carrying heavy cargo such as equipment trailers.

If a tire size begins with 'LT' it signifies the tire is a "Light Truck-metric" size that was designed to be used on trailers that are capable of carrying heavy cargo or tow vehicles. Tires branded with the "LT" designation are designed to provide substantial reserve capacity to accept the additional stresses of carrying heavy cargo.

So what is reserve capacity? It is capacity beyond the rating of the tire, capacity that is held in reserve. This reserve capacity comes from the heavy-duty sidewall of the LT type tires. LT's rank at the top of the list when we look at P, ST and LT tires.

Now I finally have an answer to how a ST tire can be rated to carry more weight than a LT tire of similar size.

The ratings of ST tires infringe into the reserve capacity of the tire. This is double bad, because the design of the ST gives us a tire with less reserve capacity to start with as it has a lighter sidewall to start with as most ST tires are much lighter than their LT counterparts.

To quote one tire site:
"Put a different way, the load carrying capacity of an ST tire is 20% greater than an LT tire. Since durability is strictly a long term issue - and the results of a tire failure on a trailer are much less life threatening than on a truck - the folks that set up these load / inflation pressure relationships allow a greater......ah......let's call it load intensity."

There it is in print to be read. They make a calculated decision to give the ST tire a higher load rating because a failure is less life threatening.

I have on a number of occasions pointed out the weight difference between the different tires and have been told that does not matter. Well it does matter. The rubber in the average tire only makes up around 40 some percent of its weight, the rest is in the steel belts, gum strips, steel beads, and the carcass plies. The remaining 60 or so percent of the stuff in a tire is what builds in the reserve capacity.

So to review again, here are some weights:
1. Michelin XPS RIB LT235/85R16 LRE (rated to 3042lbs) Weight 55.41
2. Goodyear G614 LT235/85R16 LRG (rated to 3750lbs) Weight 57.5
3. Bridgestone Duravis R250 LT235/85R16 LRE(rated to 3042lbs) Weight 60
4. BFG Commercial TA LT235/85R16 LRE(rated to 3042lbs) Weight 44.44
5. Uniroyal Laredo HD/H LT235/85R16 LRE(rated to 3042lbs) Weight 44.44
6. GY Marathon ST235/80R16 LRE(rated to 3420lbs) Weight 35.4

So which tires on the list have the most reserve capacity? Well that is not a completely simple answer, as one of the tires is a G rate 110 lb tire and the rest are LRE at 80lb inflation. So if we disregard the G614, then the Michelin XPS RIB and the Bridgestone Duravis R250 due to their all-steel ply construction will have the most reserve capacity inherent in their construction. The twin Commercial TA and Laredo will be next and the Marathon would have little or no reserve capacity available because it was used up in its higher load rating, AND because of it's much lighter construction it had much less inherent reserve capacity to start with.

So what have we learn from this?

I think that the first thing that we learned was that a LT tire can be used at or near it max rated loading without having issues, as they built with "substantial reserve capacity to accept the additional stresses of carrying heavy cargo".

The second thing we may have learned is why ST tires are failing on mid to larger 5th wheels, in that they do not have inherent reserve capacity beyond that rated max loading. Again this is because they have less reserve capacity to start with and their greater "load intensity" used up any reserve capacity that might have been available.

Now, here is an interesting bit of information. I just called Maxxis Tech Line and asked the weights for two tires.

ST235/80R16 LRD 3000 lb rating at 65 lbs of air weights 38.58
ST235/80R16 LRE 3420 lb rating at 80 lbs of air weights 43.43

What??? The Maxxis load range E tire weights almost the same as the Commercial TA?? This is a ST tire that has heavier construction than the GY Marathon at 35.4 lbs. So it has more inherent reserve capacity due to its heavier construction.

Those that claimed its virtues maybe did not know why it was a better ST tire than some of the others, but there it is! It is a heavier built tire with more reserve capacity.

So as one chooses a replacement tire or is asking for an upgrade on a new trailer please get educated on where the reserve capacity exist. Is it inherent in the tire you choose or do you have to factor it into the weight rating of the tire you choose.

Those with heavy trailers that are switching to 17.5 rims and tires rated to 4805 lbs and getting a double injection of reserve capacity, in that they are using a tire with lots of inherent reserve capacity and the tire has much more capacity than the application. It is all starting to make sense.

I have learn a bit this week, hopefully others have also.

Chris"<!-- google_ad_section_end -->

<!-- / message --><!-- sig -->
 

caissiel

Senior Member
Well Done, I have also solved my tire issues by choosing LT tires over ST. I was also told they would not work but it was fine.
 

combine_billy

Active Member
Good info. There really is no substitution for knowing what you are talking about. I have heard this issue debated many many times and have never really known for sure who was right. It sure made sense that the heavier tire was a better tire, but had no way to prove it.
 

Ray LeTourneau

Senior Member - Past Moderator
This is pretty interesting information. Especially for those just purchasing or planning to purchase the Michelins. Thanks for the post.
 

ricatic

Well-known member
Chris is a battler. He has been engaged on other sites with a couple of ST cheerleaders. He appears to haver done a lot more research than even this post states. I generally avoid the flaming war threads but he is knowledgeable and entertaining.

Ricatic
 

Happy Campers

Well-known member
It seems to me the Goodyear since it is G rated and has a higher weight rating if you need it.

1. Michelin XPS RIB LT235/85R16 LRE (rated to 3042lbs) Weight 55.41
2. Goodyear G614 LT235/85R16 LRG (rated to 3750lbs) Weight 57.5
 

jmgratz

Original Owners Club Member
The Goodyear 614's are designed specifically for trailer - towing tires. The tread is design to prevent damage to the tires when making those tight turns.
 

vangoes

Well-known member
Maybe I have my head in the sand but I really have a hard time justifying the price of the 614's. I have just replaced my "China Bombs" of 15,000 miles with Maxxis M8008 (made in Thailand) that seem have a very good reputation around all forums. According to various literature from tire manufactures, around 15,000 miles on heavy trailers is about all that can be expected on average, so thats what I got on my previous "bombs". When I was shopping for tires, the 614's was over twice the price of other tires so I just cant justify the price. As said, maybe I have my head in the sand but my previous tires served me without incidence so if the 614's wont last twice the distance why pay twice the price? Of course, with the new imports tariffs imposed last week on China import tires, this may be a mute point! 614's it would be equitable pricing!
 

TXBobcat

Fulltime
Just replaced the LT265/70R17 E1 LTX A/S RRBL tires on my Ford F250 with LT265/70R 17 E1 121R W Michelin LTX M/S2 tires. These tires are a new prodction that has just started being shipped a few months ago.

I was asking the manager about replacing my Michelin XPS Ribs with Goodyear 614 G rated. He told me to keep them because the XPS Rib would handle right at the same weight as the 614's due to the full steel cage of which they are constructed.

He told me also that they are soon going to discontinue carrying Goodyear tires do to the problems they have been seeing with them. Now I don't know if this is fact but it will be intresting to see if it comes to pass. Discount tire is one of the largest tire distributors in the nation.

Now I can not document what I was told so take it with a grain of salt.

FWIW
BC
 

bud880

Member
Thank you so for looking in to tires problem

found this thread on another web site ...... Thought it was interesting.

trailer tires explained<!-- google_ad_section_end -->

<hr style="background-color: #a3a4a6; color: #a3a4a6" size=1><!-- / icon and title --><!-- message --><!-- google_ad_section_start -->i copied and pasted this portion of a post by mike mitchell, nuwa (hitchhiker) ceo in a discussion regarding trailer tires on the nuwa owner's forum.
++++++++++++++++++++++++++++++++++++++++++++++++

"read the following and learn from this rv.net fellows research. Mike

as we banter about regarding tire types and loading, i believe that we are finally starting to understand a few important things.

i have asked many times for someone to explain how a st tire can be rated to carry more weight than a lt tire in a similar size, without a good answer.

the answer lies in what is called reserve capacity. To quote from trailer parts superstore and this same statement exist on just about every tire site:

heavy duty 'lt' truck / trailer tires
'lt' signifies the tire is a "light truck/trailer" series that can be used on trailers that are capable of carrying heavy cargo such as equipment trailers.

if a tire size begins with 'lt' it signifies the tire is a "light truck-metric" size that was designed to be used on trailers that are capable of carrying heavy cargo or tow vehicles. Tires branded with the "lt" designation are designed to provide substantial reserve capacity to accept the additional stresses of carrying heavy cargo.

so what is reserve capacity? It is capacity beyond the rating of the tire, capacity that is held in reserve. This reserve capacity comes from the heavy-duty sidewall of the lt type tires. Lt's rank at the top of the list when we look at p, st and lt tires.

now i finally have an answer to how a st tire can be rated to carry more weight than a lt tire of similar size.

the ratings of st tires infringe into the reserve capacity of the tire. This is double bad, because the design of the st gives us a tire with less reserve capacity to start with as it has a lighter sidewall to start with as most st tires are much lighter than their lt counterparts.

to quote one tire site:
"put a different way, the load carrying capacity of an st tire is 20% greater than an lt tire. Since durability is strictly a long term issue - and the results of a tire failure on a trailer are much less life threatening than on a truck - the folks that set up these load / inflation pressure relationships allow a greater......ah......let's call it load intensity."

there it is in print to be read. They make a calculated decision to give the st tire a higher load rating because a failure is less life threatening.

i have on a number of occasions pointed out the weight difference between the different tires and have been told that does not matter. Well it does matter. The rubber in the average tire only makes up around 40 some percent of its weight, the rest is in the steel belts, gum strips, steel beads, and the carcass plies. The remaining 60 or so percent of the stuff in a tire is what builds in the reserve capacity.

so to review again, here are some weights:
1. Michelin xps rib lt235/85r16 lre (rated to 3042lbs) weight 55.41
2. Goodyear g614 lt235/85r16 lrg (rated to 3750lbs) weight 57.5
3. Bridgestone duravis r250 lt235/85r16 lre(rated to 3042lbs) weight 60
4. Bfg commercial ta lt235/85r16 lre(rated to 3042lbs) weight 44.44
5. Uniroyal laredo hd/h lt235/85r16 lre(rated to 3042lbs) weight 44.44
6. Gy marathon st235/80r16 lre(rated to 3420lbs) weight 35.4

so which tires on the list have the most reserve capacity? Well that is not a completely simple answer, as one of the tires is a g rate 110 lb tire and the rest are lre at 80lb inflation. So if we disregard the g614, then the michelin xps rib and the bridgestone duravis r250 due to their all-steel ply construction will have the most reserve capacity inherent in their construction. The twin commercial ta and laredo will be next and the marathon would have little or no reserve capacity available because it was used up in its higher load rating, and because of it's much lighter construction it had much less inherent reserve capacity to start with.

so what have we learn from this?

i think that the first thing that we learned was that a lt tire can be used at or near it max rated loading without having issues, as they built with "substantial reserve capacity to accept the additional stresses of carrying heavy cargo".

the second thing we may have learned is why st tires are failing on mid to larger 5th wheels, in that they do not have inherent reserve capacity beyond that rated max loading. Again this is because they have less reserve capacity to start with and their greater "load intensity" used up any reserve capacity that might have been available.

now, here is an interesting bit of information. I just called maxxis tech line and asked the weights for two tires.

st235/80r16 lrd 3000 lb rating at 65 lbs of air weights 38.58
st235/80r16 lre 3420 lb rating at 80 lbs of air weights 43.43

what??? The maxxis load range e tire weights almost the same as the commercial ta?? This is a st tire that has heavier construction than the gy marathon at 35.4 lbs. So it has more inherent reserve capacity due to its heavier construction.

those that claimed its virtues maybe did not know why it was a better st tire than some of the others, but there it is! It is a heavier built tire with more reserve capacity.

so as one chooses a replacement tire or is asking for an upgrade on a new trailer please get educated on where the reserve capacity exist. Is it inherent in the tire you choose or do you have to factor it into the weight rating of the tire you choose.

those with heavy trailers that are switching to 17.5 rims and tires rated to 4805 lbs and getting a double injection of reserve capacity, in that they are using a tire with lots of inherent reserve capacity and the tire has much more capacity than the application. It is all starting to make sense.

i have learn a bit this week, hopefully others have also.

chris"<!-- google_ad_section_end -->
<!-- / message --><!-- sig -->
i still have these china tires on my 2008 big horn 3055, i,m looking to replace michlien xps 235/85/16e
thank u. Bud880
 

Happy Campers

Well-known member
I also have china bombs on mine but i also have the Pressure Pro to moniter them. I know the PP won't solve the problem if one of them decides to blow but I do have a little more confidence. I'm also looking at the Rib or Gy 614 when we get home.
 

jmgratz

Original Owners Club Member
All I can say is two blowouts in the first 2800 miles with Chinese made tires and none in 5000 miles with Goodyear 614s. I take Goodyear any day over China Bombs. You might feel different about your bombs when they tear up the side of your RV.
 

bigbird272

Active Member
Trailer tires are rated for a max of 65 mph. They last apporx 4 years depending on usage. The worst thing for them is sitting at a pad for months at a time. The sides give out. Most important is to keep proper pressure in them.

Rick
 

lwmcguir

Well-known member
We run our good quality American Made trailer tires for years. Many are on duals but even the singles see over 10 years of service. No problems to speak of on bad roads and maximum loading. Quality of the original tire is important. As they age they certainly are more prone to unexpected failures but should last well beyond four years under normal operation and service. I realize you are stating from the manufacturers perspective however I bet there are more tires out there that are over 4 than less than 4 years old.
 

lwmcguir

Well-known member
Just replaced the LT265/70R17 E1 LTX A/S RRBL tires on my Ford F250 with LT265/70R 17 E1 121R W Michelin LTX M/S2 tires. These tires are a new prodction that has just started being shipped a few months ago.

I was asking the manager about replacing my Michelin XPS Ribs with Goodyear 614 G rated. He told me to keep them because the XPS Rib would handle right at the same weight as the 614's due to the full steel cage of which they are constructed.

He told me also that they are soon going to discontinue carrying Goodyear tires do to the problems they have been seeing with them. Now I don't know if this is fact but it will be interesting to see if it comes to pass. Discount tire is one of the largest tire distributors in the nation.


Now I can not document what I was told so take it with a grain of salt.

FWIW
BC

We have blown out many Goodyear's, but not a single G614. Many folks had had issues with wranglers. I remember about 30 years ago we were blowing out Michelin's so it comes and goes but the better tires still usually hold up better even when there are issues.
 

Delaine and Lindy

Well-known member
Goodyear G614's,

I have ran Goodyear G614s on most or the 5th wheels we have owned and never ever had a issue. The G614's run very cool and hold the pressure very well except durning temp changes. I also run the Pressure Pro System and do monitor the pressure. I always ran 110 lbs of pressure and they will increase about 10% after warm up. We are now running Goodyear G114 17.5s and so for we haven't had a issue they require 125 lbs of pressure. I do run Mission and Freestars on my Car Trailer And Equipment trailer but would run a China made tire on my 5th wheels. GBY....

P.S. The earlier made G614s ther was some problems back in the 2003/2004 time frame. And want use the ST tires at all.
 

caissiel

Senior Member
In the last 6 month alone here is my experience.
1. Received a new trailer with 80PSI air in the tires, tag says 110PSI
2. Received a new Toyota with 30PSI , tag says 32PSI
3. Met a loaded U-Haul truck with a flat tire on the rear, He had picked up the truck and loaded it and was on the way to OHIO. I checked the tires and he had 50PSI in all remaining tires. I told him it was not his fault the company had not enough air in the tires so he bend the rim in a pot hole at the rest area entrance. The service man had no compressor on his truck to put more air in the remaining tires. There were 4 big signs showing the 80PSI requirement on the truck.
4. Changed the oil on Toyota, tire light came on, they had 24PSI on 3 tires and 28PSI on the other.
this is just the last 6 months.

I do my tire maintenance, but what if I did not. and how many people does not. Air pressure is a continuous problem, so I always use the max pressure as a guide, both for economy and endurance. These radials work best while loaded with air.

In the earlier days Michelin was the first to sell radials in Canada. Everyone was told to ride with 4 PSI less then conventional tires. The tires had broken belts everywhere an at any mileage. Blowouts were very common. I always drove with recommended air plus 4 Lbs that my car showed on the car door as usual. I never had any problem with these radial and at the time I was doing over 50K per year. In the last 36 years of driving with Radials I never experienced any with broken belts on tires and I buy tires on price can't afford Michelin's.
But I did have blowouts on the rear tires on my 5th wheel, I always blamed the thread depth of the trailer tires because it was always the rear tire that failed. Truck tires with heavier threads fixed that.
My China bombs will surely be tested, but I like the facts that the are regroovable, might prove ok.

I have to add one more the past 6 month.

I was at my friend this fall and he was doing some rim replacement on his SOB 5th wheel unit, because the rims had corroded, and he asked me what torque he should torque the nuts. Well I told him the proper torque. Then i asked him what air pressure he was using in his tires. he told me he was putting the same air pressure there was on the trailer when he got it, 60Lbs like always. He has been camping as long as I have been because we bought the 1st and second trailer together. I shook in my pants learning that my FRIEND was traveling for the past 3 years on Chinese tires with 60PSI air on Class E tires.
He had never had a trailer (14000 GVW) with class E tires before and for him 60PSI was OK. The load chart shows that 60PSI is good for around 2400Lbs and he had 6000lbs for sure on his axles if not more.
 
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