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Old 04-22-2019, 05:27 PM   #1
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tire markings

I am wanting to understand ratings and limits better. They are just the factory tires that came with it, and are probably just the typicaly "China bombs" that everyone refers to. The TIRE MARKINGS state the following:

* Ridgway Sport ST LH-001. I believe ST stands for "special trailer service tires". LH-001 is probably the tire model. Google shows "LH-001" to be a Lionhart tire, but Ridgway Sports are at a website by Lionshead in Goshen, Indiana where so mamy of these trailers are built. I THINK the website is https://lionsheadtireandwheel.com/Ri...-Bias-Ply-Tire.

* 205/75R15 is the tire size/ratios and wheel diameter, with the "R" meaning radial tires (I always thought R was for radius, but no).

* Load Range D...usually I see this associated with an 8-ply tire at 65 psi, but my tire markings show only 7 plies with a 65 psi maximum pressure (the regulatory tire sticker on the trailer side also states "ST205/75R15D", where the "D" is for load range D I believe and states 65 psi pressure). HOWEVER, what is a LITTLE confusing is that the manufacturer website shows this tire as Load Range "C" (LRC) at 50 psi. ???

* SPR107/102L...okay, let's break this down.
* The L is a speed rating corresponding to a maximum speed of 75 mph.
* I believe 107 and 102 are load INDEX corresponding with 2,149 and 1,874 lbs per tire, with the higher value applicable for dual axle situations. The tire markings round these values to 2,150 and 1,870 lbs. I presume that with dual axle and four functioning tires, I would say 2,149 x 4 = 8,596 lbs maximum that the trailer and all of its contents while traveling should weigh.
* I have NO idea what "SPR" stands for. Anyone??

Am I generally understanding things correctly? I understand there is a debate about the factory ST tires vs. light truck tires etc, but I haven't made any plans to switch anything out.
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Old 04-24-2019, 10:28 PM   #2
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I am not familiar with the SPR designation either. All of your other interpretations seem correct to me. I run D load range on my 6000# trailer and have had no problems. Remember to look at the date code on these tires and any you may buy in the future. I don't accept any tires more than six months old for obvious reasons.
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Old 04-24-2019, 10:58 PM   #3
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Originally Posted by aguablanco View Post
I am not familiar with the SPR designation either. All of your other interpretations seem correct to me. I run D load range on my 6000# trailer and have had no problems. Remember to look at the date code on these tires and any you may buy in the future. I don't accept any tires more than six months old for obvious reasons.
Agreed with date stamp. I did check that too. The date is 4717 (which is 47th week of 2017). I purchased the trailer in June 2018. So the tires would have been about 7 months or so old, which is not unreasonable for a trailer that was built in late 2017/early 2018 and then shipped to the dealer in early 2018, to be sold that summer.
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Old 04-25-2019, 04:27 PM   #4
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Quote:
Originally Posted by Hart_family View Post
I am wanting to understand ratings and limits better. They are just the factory tires that came with it, and are probably just the typicaly "China bombs" that everyone refers to. The TIRE MARKINGS state the following:
.

If they are "china bombs", should say made in China on the tire somewhere. BUT! Engineered in the USA..........haha.


Based on what I have read here and other forums. And from several friends. Here is my recommendation for any tire brand you may use,


GET TIRE PRESSURE MONITORS.


A lot of people never know the tire goes flat while on the road. It destroys the tire and then the undercarriage and then the other tire goes. By then you know



Good Luck!
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Old 04-28-2019, 02:20 AM   #5
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Quote:
Originally Posted by Hart_family View Post
I am wanting to understand ratings and limits better. They are just the factory tires that came with it, and are probably just the typicaly "China bombs" that everyone refers to. The TIRE MARKINGS state the following:

* Ridgway Sport ST LH-001. I believe ST stands for "special trailer service tires". LH-001 is probably the tire model. Google shows "LH-001" to be a Lionhart tire, but Ridgway Sports are at a website by Lionshead in Goshen, Indiana where so mamy of these trailers are built. I THINK the website is https://lionsheadtireandwheel.com/Ri...-Bias-Ply-Tire.


"Ridgway Sport might be the "Brand" with ST LH-001 being the "Design"

* 205/75R15 is the tire size/ratios and wheel diameter, with the "R" meaning radial tires (I always thought R was for radius, but no).
Yes but isn't there an ST immediately in front of the 205?


* Load Range D...usually I see this associated with an 8-ply tire at 65 psi, but my tire markings show only 7 plies with a 65 psi maximum pressure (the regulatory tire sticker on the trailer side also states "ST205/75R15D", where the "D" is for load range D I believe and states 65 psi pressure). HOWEVER, what is a LITTLE confusing is that the manufacturer website shows this tire as Load Range "C" (LRC) at 50 psi. ???


The Tire Placard aka tire sticker sticker, is suppose to identify the OE tire as supplied. Technically The sticker is not legal and should have been chengedby the MFG. BUT switching from Bias "D" to Radial "R" would not be a bad thing IMO. Now LR_D or Load Range D replaces the old "Ply Rating". No idea where you found "7" plies as most radials have 1 body ply sidewall. The tread would have 1 ply Polyester + 2 Ply Steel. It may or may not also have 1 layer of Nylon in the tread. The tire sidewall also has a statement about "65 psi and 2149 Lbs Max load


* SPR107/102L...okay, let's break this down.
* The L is a speed rating corresponding to a maximum speed of 75 mph. Yes but the load formula for ST tires is based on 65 max operating speed. while the tire may be capable of 75 for 30 minutes.
* I believe 107 and 102 are load INDEX corresponding with 2,149 and 1,874 lbs per tire, with the higher value applicable for dual axle situations. NO. The Dual means 2 tires side by side. Check my blog on "Tandem axles" (2 axles one in front of the other.The tire markings round these values to 2,150 and 1,870 lbs. I presume that with dual axle and four functioning tires, I would say 2,149 x 4 = 8,596 lbs maximum that the trailer and all of its contents while traveling should weigh. Basically yes BUT no individual tire should ever have more than 2149" and almost no trailers have the load equally split. Some RV have a heavy load tire that might have +100 to + 400 lbs more than the light load tire.
* I have NO idea what "SPR" stands for. Anyone?? Random nomenclature

Am I generally understanding things correctly? I understand there is a debate about the factory ST tires vs. light truck tires etc, but I haven't made any plans to switch anything out.

My comments in RED. I strongly suggest you confirm the info and learn more about tires by reading my RV Tire Safety blog. and YES definately get a TPMS. Preferably from a dealer that sells to the RV market not the lowest cost option on eBay or Amazon as they will not have a knowledgable person available to answer yout RV question.
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Old 04-28-2019, 03:37 PM   #6
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The ST is to designate that the tire has a thicker stronger sidewall and is specifically for trailer use. Regular passenger tires and even LT tires don't have strong enough sidewalls to put up with the stress of turning and backing that tandem+ axle trailers go through.



Regular tires can have the sidewalls damaged internally when backing into tight places, and even when making sharp turns into a parking lot, and if they hit a curb or sharp object the sidewall can become damaged without you knowing it and later blow out.



Trailer tires get scrubbed, just watch them when backing up, at times you would swear they would pop off the rims with how much flexing they do.



This is why regular tires, even LT tires are not recommended for trailers with more than 1 axle. Single axle trailers don't have this problem.
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Old 04-28-2019, 03:44 PM   #7
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If it is made in china then replace it NOW. Also get you rig weighed loaded so you know what the axle and tongue weight is.
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Old 04-28-2019, 04:01 PM   #8
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Originally Posted by acdii View Post
The ST is to designate that the tire has a thicker stronger sidewall and is specifically for trailer use. Regular passenger tires and even LT tires don't have strong enough sidewalls to put up with the stress of turning and backing that tandem+ axle trailers go through.
Regular tires can have the sidewalls damaged internally when backing into tight places, and even when making sharp turns into a parking lot, and if they hit a curb or sharp object the sidewall can become damaged without you knowing it and later blow out.
Trailer tires get scrubbed, just watch them when backing up, at times you would swear they would pop off the rims with how much flexing they do.
This is why regular tires, even LT tires are not recommended for trailers with more than 1 axle. Single axle trailers don't have this problem.

Well as an actual Tire Engineer, I know that is the story some salesmen like to tell but if you actually do a section analysis you will not find much if any difference in the tire sidewall.
The primary damage from the turning & backing is in the steel belt area and is called "Interply Shear". This force is significantly higher in tandem trailer use than in use on cars or trucks. This shear force initiated cracks in the rubber which grows with use and you can end up with belt separations.


Sidewall failures, that many incorrectly call "blowouts", are in fact "Run low flex failures" as covered in this tire autopsy.


The "ST" just identifies the Type tire. These tires use different load calculations which are based on an assumed 65 mph max operating speed. Tires with higher Speed Symbol ratings just need to run for 30 minutes and not fail to achieve that symbol.
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Old 04-28-2019, 04:08 PM   #9
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tires

Why can't the RV industry do something about these tires called China bombs. That is what the manfactures put on these rv's and then we are stuck with them. When they blow, they usually damage the side of the rv or trailer and cause over 1000.00 in damage and not to mention the danger of a blowout and changing a tire on the highway. These RV should have the best tires that can be bought due to the serious natures of blowouts. Most people buy new tires for the auto or truck that have 50,000 mile warranties and for the most part they exceed that mileage. With rv's it's more about the age of the tire because most will never see 10,000 miles before blowouts. The RV industry needs to stand up and put the best tires on their products because most consumers don't know the good ones and the Chinal bombs.
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Old 04-28-2019, 04:14 PM   #10
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Why can't the RV industry do something about these tires called China bombs. That is what the manfactures put on these rv's and then we are stuck with them. When they blow, they usually damage the side of the rv or trailer and cause over 1000.00 in damage and not to mention the danger of a blowout and changing a tire on the highway. These RV should have the best tires that can be bought due to the serious natures of blowouts. Most people buy new tires for the auto or truck that have 50,000 mile warranties and for the most part they exceed that mileage. With rv's it's more about the age of the tire because most will never see 10,000 miles before blowouts. The RV industry needs to stand up and put the best tires on their products because most consumers don't know the good ones and the Chinal bombs.



I don't know if you noticed, but RV's use the cheapest crap they can get away with. I 100% believe they don't care.
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