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Old 09-03-2018, 08:54 PM   #41
CWtheMan
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Remember the basics when searching for replacement tires. They must have the ability to equal the load capacity of the Original Equipment tires. That's a industry wide safety standard.

There are no suitable 16" LT tires with a load capacity equal to the load capacity of 16" ST tires. The 16" steel cased LRG LT tires are really trailer tires and have the RST right on their sidewalls. The RST is a registered trade mark from Goodyear meaning Regional Service Trailer.

In most cases there is nothing to prevent you as an owner to do as you see fit. However, discarding established safety standards for your own personal standards puts the responsibility for those actions squarely on your shoulders, so to speak.
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Old 09-04-2018, 06:44 PM   #42
Irv gates
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AJ... Right on about those Michlin XPS tires. I have been running those tires on my last two Fivers and I have had no flats ,no problems for the last ten years. Iam on the First set now on my 2014 Montana ,a 39ft trailer and just put 4000mi in the last Two months on the trailer without any hipcups.
Also remember that trailer tires do not care the same specs for safety as do Autos and Lt trucks.
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Old 09-05-2018, 02:42 AM   #43
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Alright, I'll poke the stick this time.
Irv, "trailer tires do not care the same specs for safety as do Autos and Lt trucks."
We need to have you explain this in a little detail.
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Old 09-05-2018, 12:56 PM   #44
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Alright, I'll poke the stick this time.
Irv, "trailer tires do not care the same specs for safety as do Autos and Lt trucks."
We need to have you explain this in a little detail.
His trailer probably has 5200# axles which allows the EPS Ribs to provide more than enough load capacity reserves. However, no reputable retail tire store will knowingly replace Original Equipment ST tires with LT tires of any brand with the exception those manufactured strictly for trailer service.

All tires certified safe for highway service have the DOT logo on their sidewalls. So, you're right, where is your lack of safety reference Irv.
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Old 09-21-2018, 07:29 PM   #45
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His trailer probably has 5200# axles which allows the EPS Ribs to provide more than enough load capacity reserves. However, no reputable retail tire store will knowingly replace Original Equipment ST tires with LT tires of any brand with the exception those manufactured strictly for trailer service.

All tires certified safe for highway service have the DOT logo on their sidewalls. So, you're right, where is your lack of safety reference Irv.

Wondering what would be wrong with replacing tire "A" with tire 'B" if it has a greater load capacity than "A".



I do not think the letters ST bestow some "magic" capability that tires marked LT don't?
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Old 09-21-2018, 09:08 PM   #46
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Originally Posted by Tireman9 View Post
Wondering what would be wrong with replacing tire "A" with tire 'B" if it has a greater load capacity than "A".



I do not think the letters ST bestow some "magic" capability that tires marked LT don't?
It’s a technicality I’ve researched extensively. To track it you have to start at the governing body, at the point where a decision was made determining responsibility for original equipment fittings. NHTSA has determined the vehicle manufacturer is solely responsible for tire selection and fitment on – let’s say – RV trailers.

NHTSA also sets the minimum safety standard for those original equipment tire fitments which are described in the FMVSS (standards).

Tire designated size and its recommended cold inflation pressures MUST be displayed on the trailer’s federal certification label, in the trailer’s owner’s manual and on the tire & load label. The trailer manufacturer must provide documentation to the governing body that the federal certification label information is correct for that vehicle. NHTSA requires the vehicle owner’s manual describe general tire safety information. Within those descriptions there is a standard statement that informs the owner to use replacement tires of the same size and load capacity as the original tires described on the certification label. The trailer manufacturer can authorize options.

Tire industry standards (IMO) are nearly 100% in agreement with a statement that is worded similar to this one: Tires should always be replaced with the same size designation — or approved options — as recommended by the vehicle manufacturer. The correct tire size designated for your vehicle should always be verified with the information in your vehicle owner’s manual.

NOTE: A tires size designation includes the prefix. Therefore, ST235/80R16 is a tire designed for trailer axles only. LT235/85R16 is a tire designed for drive/steer axles only. IMO that’s the way the tire industry sees it.

Also, IMO, you will be hard pressed to get any trailer manufacturer to budge from their tire selection for your RV trailer. Reputable tire retailers go by what’s recommended on the vehicle labeling or recommended by the vehicle manufacturer.

I’ve never found any good reason why RV trailer builder “A” put ST235/80R16 LRE tires on 6000# GAWR axles when RV trailer builder “B” has certified LT235/85R16 LRE for the same sized axles on their brand of RV trailer. I don’t think we’ll see much of that anymore because of the 10% load capacity reserves recommended by RVIA for all tire fitments on RV trailer axles.
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Old 09-22-2018, 07:22 AM   #47
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All part of the marketing trap the ST tire manufacturers have created. Thankfully with the new GY ENDURANCE we may have a ST that can meet the claims made for so many years. With the new 10% cushion hopefully all 7K axles will get LRG all steel ply tires. In the mean time a lot of rubber was left on the roads. Chris
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Old 09-22-2018, 09:44 AM   #48
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All part of the marketing trap the ST tire manufacturers have created. Chris
If there was such a thing as a "marketing trap" conjured up by any tire manufacturers it was a necessary thing. USA tire manufacturing plants from the get-go have purposefully steered away from manufacturing ST tires. For the most part, they sent their molds and designs to other nations and washed their hands.

President Trump is tired of the trade deficit with China. Odds are he will soon void any/all tariff relief the China ST tire manufacturer's now receive. Some of the China manufacturer's have already made plans on moving their ST tire manufacturing to USA plants. One in NC is already providing ST tires to retailers.

Because a tire is manufactured in the USA does not guarantee a better product. The basic design remains the same wherever it's manufactured.
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Old 09-23-2018, 08:02 AM   #49
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Tire replacement

The tire industry position, I worked under for 40 years, was that any replacement tire should be capable of supporting equal or greater load as the OE tire did.


My post was simply intended to point out that replacing an ST type with LT type where the numbers were the same would result in lowering the load capacity. Not everyone pays attention to the details of the load and inflation information on either their Tire Placard or molded on the tire sidewall.


With the change in RVIA guidelines (adding 10% margin Sept 2017) it seems to me the correct thing to do is to ensure that ANY new tire you get for your RV should be able to meet that new guideline. There are millions of RVs out there with old placards that have 0% margin.


RV companies are not required to change the old placard so they would not go the expense.


Not sure how or why you would advise people to ONLY use the original size & type tire when the industry guidelines have been updated and improved.


Did the Navy never make changes or improvements to ships or aircraft, years after the ship or aircraft was built? You probably got new maintenance manuals and were told to stop following the original spec sheet. RV companies are not like the Navy. They wash their hands of any responsibility or care for the RV once it leaves the dealer lot.


IMO tires built to DOT standards that were upgraded in 2003 are much better than the out of date standards written in 1970.
IMO FMVSS 571.139 should be followed for all current P, LT & ST tire production but the RV industry fought against the inclusion of ST tires in that standard as they knew it would make tires more expensive even though the end user would get a better and more durable product.
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Old 09-23-2018, 09:07 AM   #50
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Did the Navy never make changes or improvements to ships or aircraft, years after the ship or aircraft was built? You probably got new maintenance manuals and were told to stop following the original spec sheet. RV companies are not like the Navy. They wash their hands of any responsibility or care for the RV once it leaves the dealer lot.

Sorry Tireman9, My goal is to write it the way it's supposed to be, not to what is good for the goose. Most of the current standards were approved in 2007. However, NHTSA and the tire industry keep safety standards current with bulletins, addendums and such.

As I said earlier, the trailer manufacturer is solely responsible for OE tires. Because the FMVSS enforces minimum standards, OE tires are considered a minimum guidance for replacements. Because NHTSA and the tire industry have reinforced tire descriptions, any prefix in the tire size description (P, LT, ST) is part of it's official size description. When the vehicle certification label reads ST225/75R15 the ST tire design is locked-in because of vehicle certification and numerous other NHTSA/tire industry standards.


Is it unsafe to use tires that are from a different design to replace your trailer tires? Probably, if you follow the established tire industry standards for such replacements. However, IMO, if such replacements were ever investigated for safety violations the plus sized tires would be a misapplication if not recommended by the vehicle manufacturer for that fitment.


There are always exceptions and arguments. An exception would be a tire with a LT prefix in it's size designation but is clearly designated by it's manufacturer as being for trailer service only and that info is molded onto its sidewall.


A strong argument could be won when 225/75R17.5 sized tires are used and they were designed for low platform trailer service.
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Old 09-23-2018, 09:21 AM   #51
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They wash their hands of any responsibility or care for the RV once it leaves the dealer lot.

Not entirely. They can't afford to. Self initiated recall action is hardly ever accompanied with NHTSA monitor penalties.

NHTSA initiated recall actions can be very expensive with very high monitory penalties.


Because of that, Keystone does listen to safety complaints and takes action when warranted.


NOTE: All should keep in mind that a complaint against equipment is not a complaint against Keystone. They may be involved with any recall action but the equipment provider will be paying. You should keep that in mind when your trailer is severely damaged from a catastrophic tire/wheel failure.
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Old 09-24-2018, 07:27 AM   #52
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Sorry Tireman9, My goal is to write it the way it's supposed to be, not to what is good for the goose. Most of the current standards were approved in 2007. However, NHTSA and the tire industry keep safety standards current with bulletins, addendums and such.

As I said earlier, the trailer manufacturer is solely responsible for OE tires. Because the FMVSS enforces minimum standards, OE tires are considered a minimum guidance for replacements. Because NHTSA and the tire industry have reinforced tire descriptions, any prefix in the tire size description (P, LT, ST) is part of it's official size description. When the vehicle certification label reads ST225/75R15 the ST tire design is locked-in because of vehicle certification and numerous other NHTSA/tire industry standards.

Is it unsafe to use tires that are from a different design to replace your trailer tires? Probably, if you follow the established tire industry standards for such replacements. However, IMO, if such replacements were ever investigated for safety violations the plus sized tires would be a misapplication if not recommended by the vehicle manufacturer for that fitment.

There are always exceptions and arguments. An exception would be a tire with a LT prefix in it's size designation but is clearly designated by it's manufacturer as being for trailer service only and that info is molded onto its sidewall.

A strong argument could be won when 225/75R17.5 sized tires are used and they were designed for low platform trailer service.

Key word is "minimum" requirement.


Should we interpret your position to mean that if someone had a 2015 RV with an ST225/80R16LR-E but the 2017 model of the same RV with the same GVWR comes with LT235/85R16 LR-G you would say it is incorrect for the owner to go to the LT235's because that was not the size originally approved?
I am not aware of any RV company or car company issuing bullitins suggesting new or better tires on older model trailers. Doesn't the Navy do updates?


If the owner increases the load capacity of the tires please give us the technical reason why this would be bad or why it would not improve the safety of the RV as with going from 0% margin to 10% margin would clearly be an improvement IMO.



If you disagree then I guess folks will need to decide if they want to listen to an actual tire engineer or someone with just an interest in tires
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Old 09-24-2018, 08:45 AM   #53
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In my case my 2014 Alpine came with ST235/80x16E rated 10 ply TK tires.. I upgraded shortly after to LT235/85x16 14 ply G rated tires.. the stock wheels are stamped 110 psi...

2015 Alpine, same model came stock with Provider 235/85x16 tires and same wheels..

Suspension on both years is exactly the same, as are the axles...7K...

It’s obvious to me Keystone knew they had an issue and corrected it on all 2015 Alpines...

Just wrapped up fifth season with my off brand Geo Star tires sold by Les Schwab tires.. I know my rig is safe and I have no worries and could care less what the factory placard states for tire size that it came with...
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Old 09-24-2018, 08:48 AM   #54
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Key word is "minimum" requirement.


Should we interpret your position to mean that if someone had a 2015 RV with an ST225/80R16LR-E but the 2017 model of the same RV with the same GVWR comes with LT235/85R16 LR-G you would say it is incorrect for the owner to go to the LT235's because that was not the size originally approved?

It's the manufacturer's prerogative and fully supported by FMVSS. It clearly states in the standards that the manufacturer is to fit each trailer with tires they deem appropriate. You cannot change their way of thinking any more than you can change mine.

I am not aware of any RV company or car company issuing bulletins suggesting new or better tires on older model trailers. Doesn't the Navy do updates?

Numerous tire manufacturer's produce bulletins parodically. Toyo seems to have the longest listings. Of course the Navy does updates. They also do some that are retroactive.


If the owner increases the load capacity of the tires please give us the technical reason why this would be bad or why it would not improve the safety of the RV as with going from 0% margin to 10% margin would clearly be an improvement IMO.


I'm sorry if you got the impression I disapprove of increasing existing tire load capacity. There is a right way to do it. As long as It's not done arbitrarily. Increasing a load range from "D" to "E" changes nothing but the load capacity of the tire. The designated size is the same. The tire placard remains valid because both load ranges use the same load inflation chart. To be in compliance with the vehicle manufacturer, an owner should seek their advice before considering design changes or plus sizing. Says so right in the owner's manual. Besides that, it's done by proxy for all normal automotive tire replacements.



If you disagree then I guess folks will need to decide if they want to listen to an actual tire engineer or someone with just an interest in tires

You often give answers outside of the ropes. I strive to avoid that. (aka; FastEagle, Airdale, BlackAces and others.
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