Things to know about trailer tires

[cwhitis]

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[MilCop4523]

Originally Posted by cwhitis

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This is exactly the reason i stopped using my Ipad for messages...

[MilCop4523]

Originally Posted by dustman_stx

I'm no tire expert, but I can tell you that I for one would be WAAAAAAYYYY more comfortable towing my camper with LT tires that were rated to carry the load. And I wouldn't cringe and glance at the TPMS monitor every time I accidentally break 65mph on a downhill run.

We couldnt locate LT tires for our 5th wheel so stuck with the ST in an E load rated cat.
Tire prerssure monitoring system 507's from Truck Systems Tech. work great. At 120 kms an hour on a down hill run there is not enough time for the sensors to note an indrease in pressure or temp.

we had LT's on our 2012 Salem TT that were good for the weight - guess we were lucky but then again there is a reason why LT's are for vehicles and ST's are for non turning tires which get tire scrub backing into spots.

[spock123]

Originally Posted by gljurczyk

I do not know that much about tires and the difference. What I do know is that Black Tires in lumberton NC , said that they would not be able to put anything but ST on my trailer. So I bought 4 new Marathons from them and he moved me up to D rated from the Trail Express C rated that came with my unit. I did have about 7000 miles on them when I had a sudden blow out. I had Marathons on my Jayco before, never a problem. So I stuck with the Marathons ST. Black tire is one of the largest Good year dealers around. I was surprised when he said he would not sell me anything else. so far I have atleast 4000 miles on these and they look brand new. I just figured that's there business and they know what they are talking about. He also made me balance them or he would not sell them to me, he said that if I want to go somewhere else that would be fine. But they will not do something that they thought was unsafe. Made me feel like I bought the right tires for my unit.

If you have st tires on your camper then you have rims that are stamped st and you can't put LT tires on a st rim. My Cedar Creek 30RL had Westlake st tires on camper, I put a TPMS on tires, they served me well. The Cedar Creek 32RL came with Goodyear LT tires and should I trade anytime soon for a 36CKTS the Goodyear LT tires will be put on new camper



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[TURBS]

Originally Posted by spock123

If you have st tires on your camper then you have rims that are stamped st and you can't put LT tires on a st rim.
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With all do respect, say's who?

[Tireman9]

Originally Posted by spock123

If you have st tires on your camper then you have rims that are stamped st and you can't put LT tires on a st rim. My Cedar Creek 30RL had Westlake st tires on camper, I put a TPMS on tires, they served me well. The Cedar Creek 32RL came with Goodyear LT tires and should I trade anytime soon for a 36CKTS the Goodyear LT tires will be put on new camper
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Would really be interested is seeing a rim stamped ST type tire only. I find nothing in the US Tire & Rim Association about any such restrictions nor do I know of any bead fit requirements or differences in St type tires as they fit on wheels.

[Tireman9]

To all those that run into tire dealers that refuse to mount LT type tires on trailers have you asked to see any company documentation that supports this position? Also has anyone asked how do they plan to handle tires on trailers that were delivered with LT type tires?

Yes there are things that must be taken into account when considering changing from ST to LT type tires.

To those dealers I would also ask if they refuse to change tire size on a passenger car and do they refuse to apply tires with lower Load Index or Speed rating than came OE on the car?

[Airdale]

Originally Posted by Tireman9

To all those that run into tire dealers that refuse to mount LT type tires on trailers have you asked to see any company documentation that supports this position? Also has anyone asked how do they plan to handle tires on trailers that were delivered with LT type tires?

Yes there are things that must be taken into account when considering changing from ST to LT type tires.

To those dealers I would also ask if they refuse to change tire size on a passenger car and do they refuse to apply tires with lower Load Index or Speed rating than came OE on the car?

I know you must know this; Vehicle manufacturers are the only ones authorized to select and fit OE tires. Once selected they are described on the vehicle's federal certification label, tire placard and in the owner's manual.

With few exceptions ST tires and LT tires are not manufactured in the same sizes. When they are, the load capacity of the ST tire is far greater than the LT tire.

To compound the difficulty of doing things right many of the major LT tire manufacturers have worded their warranty packages with statements that disallow ST tires as replacements for LT tires. Michelin has a statement in their warranty package that disallows using replacement tires that conflict with safety warnings in your vehicle's owner's manual. Most RV trailer manufacturers using ST tires as OE without designating options will only recommend ST tires as replacements.

Misapplication is a key word. What does it mean? I've asked a number of knowledgeable people with reference to ST and LT tires. The common answer is based on the vehicle manufacturer's selection for OE tires. It seems that because the LT tires is not specifically designed for service on trailer axles it is a misapplication to use them to replace the ST tire which is specifically designed for trailer axle service.

The FMVSS are not binding on the public at large but very binding for the vehicle manufacturer. In 571.120 the manufacturer is directed to select tires with a minimum load capacities equal to the vehicle's certified GAWR. But, the wording also leaves room for other considerations and uses the phrase "appropriate for that fitting" and go on to also instruct the vehicle manufacturer to set the recommended cold tire inflation pressures for the OE tires. When we take the inflation pressures to the load inflation chart for the OE tires we find the minimum load capacity as set by the vehicle manufacturer as per FMVSS regulations.

Every RV trailer owner's manual I have read (and I read a lot of them at RV shows) only recommends replacement tires of the same size and load capacity be used. Or, others recommended by the vehicle manufacturer.

Every approved tire plus sizing procedure I've read tells the installer - in part - to check the tire placard to insure the replacement tires have the load capacity to equal or exceed the OE tires. Will this sometimes allow the use of LT tires? I used to think so until all the new warranty packages started using wording to disallow that possibility. Are LT hybrid tires suitable for trailer service. That's what their manufacturer says so it must be so. But, there are few of them.

[OldCoot]

You can buy any tire that will fit your trailer wheels and take the tires and wheels to any business that mounts/balances them and I'll wager they won't even ask what kind of vehicle they go on. All this talk about tire dealers refusing to mount LT tires on a trailer is hogwash, just find another dealer to mount them.

[spock123]

Originally Posted by OldCoot

You can buy any tire that will fit your trailer wheels and take the tires and wheels to any business that mounts/balances them and I'll wager they won't even ask what kind of vehicle they go on. All this talk about tire dealers refusing to mount LT tires on a trailer is hogwash, just find another dealer to mount them.

You are right about that


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[spock123]

Originally Posted by Tireman9

Would really be interested is seeing a rim stamped ST type tire only. I find nothing in the US Tire & Rim Association about any such restrictions nor do I know of any bead fit requirements or differences in St type tires as they fit on wheels.

I crawled under my 30RL and with a flashlight I found st stamped on the rims


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[Scotty]

Originally Posted by spock123

If you have st tires on your camper then you have rims that are stamped st and you can't put LT tires on a st rim. My Cedar Creek 30RL had Westlake st tires on camper, I put a TPMS on tires, they served me well. The Cedar Creek 32RL came with Goodyear LT tires and should I trade anytime soon for a 36CKTS the Goodyear LT tires will be put on new camper



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Nothing stamped to that effect on my 2015 Hemisphere 15" rims. Does have capacity and some other info, but nothing stating what type tires can be used.

[MilCop4523]

"ST tire designation: ST stands for Special Trailer tire. ST tires are designed for use on trailer axle positions only. They are not designed for the load or traction requirements of a drive or steering axle. ST tires have strengthened sidewalls to prevent the tire from rolling under the rim in turns and when cornering. All ST tires have a maximum speed rating of 65 mph. ST tires feature materials and construction designed to meet the higher load requirements and demands trailer towing presents.
Tim Fry, senior development engineer with Goodyear Tire & Rubber Company stated,“The major difference is reflected in the polyester cords used in ST tires. These cords are bigger than they would be for a comparable P or LT tire. Typically, the steel wire also has a larger diameter or greater tensile strength to meet the additional load requirements. Because of the heavier construction for an equal volume of air space, an ST tire is designated to carry more load than a P or LT tire.”
LT tire designation: LT stands for Light Truck tire. One definition atwww.tiresafety.com defines an LT tire as any tire line or size which would typically be applied on a light truck (SUV, pickup, van). As such it could be an LT-metric tire for use on a one-ton truck or a P-metric ‘light truck’ size of a typical tire used on an SUV. Light trucks (pickups) and SUVs differ from standard passenger cars in their overall strength, load carrying capacity, center of gravity, and driveline complexity. For this reason, the tire options for light trucks and SUVs are often more complex than passenger cars. Factors such as load range, ply rating and sizes vary greatly from those of passenger car applications."
Borrowed from this site...
Trailer Towing – ST Tires vs. LT Tires | RV 101® your education source for RV information

[Tugboat95]

Originally Posted by OldCoot

You can buy any tire that will fit your trailer wheels and take the tires and wheels to any business that mounts/balances them and I'll wager they won't even ask what kind of vehicle they go on. All this talk about tire dealers refusing to mount LT tires on a trailer is hogwash, just find another dealer to mount them.

Exactly my thoughts. Getting too technical. I've never had problem putting any tire on any rim I own, 4 vehicles, three trailers plus one I Just sold.

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[Oaklevel]

All I can tell you is Cunningham Tire in Bassett,VA, Danville, VA and Eden NC will not put LT tires on a trailer period. David the owner did ask if it were a trailer (Last week I got tires for one of the smaller Fruehauf utility trailers). The tires were on the 1980 six lug rims but he would not put LT tires back on it. I carried the rims in did not take the trailer.

My 13,000 lb flat 2007 trailer (different trailer) have trailer use only stamped on the rims.... 8 lug. I would post a pic but I am in Myrtle Beach.

[Tireman9]

Originally Posted by Airdale

I know you must know this; Vehicle manufacturers are the only ones authorized to select and fit OE tires. Once selected they are described on the vehicle's federal certification label, tire placard and in the owner's manual.

With few exceptions ST tires and LT tires are not manufactured in the same sizes. When they are, the load capacity of the ST tire is far greater than the LT tire.

To compound the difficulty of doing things right many of the major LT tire manufacturers have worded their warranty packages with statements that disallow ST tires as replacements for LT tires. Michelin has a statement in their warranty package that disallows using replacement tires that conflict with safety warnings in your vehicle's owner's manual. Most RV trailer manufacturers using ST tires as OE without designating options will only recommend ST tires as replacements.

Misapplication is a key word. What does it mean? I've asked a number of knowledgeable people with reference to ST and LT tires. The common answer is based on the vehicle manufacturer's selection for OE tires. It seems that because the LT tires is not specifically designed for service on trailer axles it is a misapplication to use them to replace the ST tire which is specifically designed for trailer axle service.

The FMVSS are not binding on the public at large but very binding for the vehicle manufacturer. In 571.120 the manufacturer is directed to select tires with a minimum load capacities equal to the vehicle's certified GAWR. But, the wording also leaves room for other considerations and uses the phrase "appropriate for that fitting" and go on to also instruct the vehicle manufacturer to set the recommended cold tire inflation pressures for the OE tires. When we take the inflation pressures to the load inflation chart for the OE tires we find the minimum load capacity as set by the vehicle manufacturer as per FMVSS regulations.

Every RV trailer owner's manual I have read (and I read a lot of them at RV shows) only recommends replacement tires of the same size and load capacity be used. Or, others recommended by the vehicle manufacturer.

Every approved tire plus sizing procedure I've read tells the installer - in part - to check the tire placard to insure the replacement tires have the load capacity to equal or exceed the OE tires. Will this sometimes allow the use of LT tires? I used to think so until all the new warranty packages started using wording to disallow that possibility. Are LT hybrid tires suitable for trailer service. That's what their manufacturer says so it must be so. But, there are few of them.

Yes I do understand what you are saying and I know about the vehicle manufacturers responsibilities.
What I don't understand is how RV companies can claim the tires they select are the only ones appropriate for use on the RV given that they are not willing to stand behind their choice and offer a meaningful warranty on the tires they have selected. Can you provide a list of RV companies that offer multi-year warranties on these special tires that were so carefully selected by the RV company?

IMO the "misapplication" is not much more than a back door escape clause to be used when a company does not want to stand behind their product or when they can point to the fact that the change from OE size resulted in a decrease in load capacity or lower speed capabilities or perhaps the use of a highway tire in off-road application or summer tire in winter driving.

Could you provide links to warranty literature that says that the use of an LT tire in any application where an LT was not the OE application would void the warranty?

Given your apparent position, I trust that you would consider it a misapplication if an owner wanted to use LT type tires on small pick-up trucks that were delivered with passenger type tires. Maybe you could ask one of those knowledgeable people to contact me so they can educate me as to the design features in an LT tire that would make it deficient for application on a trailer or make it somehow deficient if ever used on a small pick-up that was delivered with passenger type tires.

The concept that an LT type tire that exceeds both the load capacity and speed rating and warranty time of the ST tire it was replacing is somehow deficient seems like a long stretch considering the fact that the RV company can not demonstrate having done any technical evaluation for the selection of tires for use on the RV other than meeting the needed load capacity published in some letter of booklet.
I have never heard the term "LT Hybred" before. It is not recognized in US Tire & Rim Association spec book. Where can I learn about this new type of tire?

The strict rule that only the replacement of the OE tire with an exact replacement creates significant problems for a few trailer owners. I have identified a few applications when the tire selected and provided by the RV company does not follow the published load and inflation tables and in fact is only allowed because that specific tire importer submitted a letter to NHTSA claiming that the tire was capable of carrying the load that would allow the tires to meet the load capacity requirements in federal regulations. I got this information directly from NHTSA when questioning how it was legal for a tire to be supplied when the load capacity molded on the tire did not meet the GAWR. Nowhere in the literature from the RV company was the manufacturer of that brand tire identified as the only acceptable replacements.

As a side note. In all that RV literature that you read have you ever seen a mention of the max speed rating of the tires the RV company has selected as appropriate? I would think that this is an important bit of information for them to provide the prospective owner of the RV.

[Tireman9]

Originally Posted by spock123

I crawled under my 30RL and with a flashlight I found st stamped on the rims


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Verrrry interesting. I won't ask you t0 crawl under the TT again but is there something in your owner's manual mentioning the special rims?

How about the tire size, brand, speed rating or laod capacity?

Along with the letters 'ST" is there other information or numbers stamped on the rim?

This is completely new information for me so I want to gain a full understanding about this new rim marking especially since I can not find any mention of it in the standards books.

[Tireman9]

Originally Posted by Oaklevel

All I can tell you is Cunningham Tire in Bassett,VA, Danville, VA and Eden NC will not put LT tires on a trailer period. David the owner did ask if it were a trailer (Last week I got tires for one of the smaller Fruehauf utility trailers). The tires were on the 1980 six lug rims but he would not put LT tires back on it. I carried the rims in did not take the trailer.

My 13,000 lb flat 2007 trailer (different trailer) have trailer use only stamped on the rims.... 8 lug. I would post a pic but I am in Myrtle Beach.

Next time you see Dave you might ask him if he would refuse to mount LT tires on a trailer that was manufactured and sold with LT type tires as Airstream does with some of its TT and if he would refuse to put LT tires of say a F150 that Ford made with P type tires.

[Witch Doctor]

Originally Posted by Tireman9

Verrrry interesting. I won't ask you t0 crawl under the TT again but is there something in your owner's manual mentioning the special rims?

How about the tire size, brand, speed rating or laod capacity?

Along with the letters 'ST" is there other information or numbers stamped on the rim?

This is completely new information for me so I want to gain a full understanding about this new rim marking especially since I can not find any mention of it in the standards books.

My rims are not stamped anywhere ST only. My situation was that Black tire in NC just refused to put on anything except ST. That could be there policy, they also said that, I have the opportunity to have another shop put on LT. But they refused by there policy and I guess what they think is a liability issue. Is there one I doubt it, but that is there policy. They also read the pressure rated stamped inside, and said the most I could move up was from "C" to "D". So I bought Marathon ST "D" rated....

[gectisme]

MilCop4523,
Let preface this by saying I am new to TT's so I am in a heavy learning curve.

My WindJammer has ST225/75R15 tires and they have a speed rating of 75mph, why do you say all ST tires have a max speed rating of 65? Maybe I am missing some info?