Yes another Tire Thread and another question

[brooks340]

OP I have the same model, 294RL and I put Sailuns on 2 months after I bought it. I stayed with the 80s and they have been great you won't regret it.

[phillyg]

Sailun calls for rim width 6-7.5" for both the 80 and 85 aspect tires. The width of the 80 tire is 9.25" vs 9.30" for the 85, a whopping 0.05". I don't think anyone can convince me its a bad thing to go to the 85, regardless of the mfgrs. placard, unless the wheels are too close together and/or there's inadequate clearance at the wheel well.

[SJ294]

From first hand experience ,yes change the tires out to Sailun G rated. I blew a tire F rated "China Bomb" tire with less than 2 k that caused $5200 in damage. The tire exploded like a bomb, blew the cross braces out on the drivers side slide, took out the wiring, gas line & rear stabilizer. I had always planned to replace the F's anyway but didnt think it would be that soon. The remaining 3 tires were actually delaminating and it was only a matter of time. BTW tires were not covered by warranty. Spend the money now!!

[Gonefishin]

Originally Posted by Rlates

All,

First off, new to the club. Looking forward to gaining knowledge from everyone with years of experience.

I know there are a ton of opinions on tires and from all the research I have done I think I have it down to two selections, Wife and I just purchased a 2021 Keystone Montana 295RL (which we really like). The tires are ST235/80R 16F (12 ply).

Looking to upgrade the tires to:

Sailun ST 235/80R 16 G9 Rated/14ply (all steel)



Hercules ST235/80R 16 H-901 (G rate/14 ply all steel)

Any opinions on either?

Second, could I put 85Rs on the 295RL model?


Lastly, my Black tank sensor always reads 1/2 even when drained. Any helpful hits?

I have the Hercules on my 3950BR. Just finished a 5,000 mile trip from St. Louis thru Colorado to San diego and back. Not a mark on them. No experience with the Sailun but heard they are good.

Forget the sensor on your black tank. It's worthless. I would buy a Valterra flushking valve so you can back flush your tanks. You won't believe what your get out of your black tank. May help with your sensor but still wouldn't trust it.

[SJ294]

Learned this trick from a GOB traveling for years. If traveling on a 4+ hour trip I put 5 gallons of water in each grey tank, 2 cups of liquid dish soap. On the Black I do the same as grey tanks but add a bag of ice. by the time we reach next stop tanks are clean. But for the most part the sensors are junk and this trick wont work all the time.

[CalandLinda]

Originally Posted by phillyg

Sailun calls for rim width 6-7.5" for both the 80 and 85 aspect tires. The width of the 80 tire is 9.25" vs 9.30" for the 85, a whopping 0.05". I don't think anyone can convince me its a bad thing to go to the 85, regardless of the mfgrs. placard, unless the wheels are too close together and/or there's inadequate clearance at the wheel well.

When you dig into the regulations and standards you'll find it's a safety violation.

Some regulations have seniority over others. 49 CFR is a Code of Federal Regulations. Therefore, when active, they set precedence over lower ranking regulations such as NHTSA & FMVSS. This is a designated tire size; ST235/80R16; this is a different tire size; ST235/85R16. 49 CFR 570.62 does not allow a major deviation in OE tire sizes. They do not give an explanation for "major deviation". However, the tire industry (USTMA) will not deviate from that unless the vehicle manufacturer offers options.

In the standards used by trailer manufacturers (FMVSS), they are directed to use a tire designated size when inflated to the recommended cold inflation pressure is appropriate for that vehicle. The vehicle manufacturer is required to certify those fitments and inflation pressures.

Tire industry standards (USTMA) requires all replacement tires to be of the same designated size as the OE tires unless there are vehicle manufacturer approved options.

Note: Going up with a load range (LRD to LRE) has nothing to do with a tire's designated size. Both load ranges will provide identical load capacities at 65 PSI.

[kowbra]

Originally Posted by CalandLinda

When you dig into the regulations and standards you'll find it's a safety violation.

Some regulations have seniority over others. 49 CFR is a Code of Federal Regulations. Therefore, when active, they set precedence over lower ranking regulations such as NHTSA & FMVSS. This is a designated tire size; ST235/80R16; this is a different tire size; ST235/85R16. 49 CFR 570.62 does not allow a major deviation in OE tire sizes. They do not give an explanation for "major deviation". However, the tire industry (USTMA) will not deviate from that unless the vehicle manufacturer offers options.

In the standards used by trailer manufacturers (FMVSS), they are directed to use a tire designated size when inflated to the recommended cold inflation pressure is appropriate for that vehicle. The vehicle manufacturer is required to certify those fitments and inflation pressures.

Tire industry standards (USTMA) requires all replacement tires to be of the same designated size as the OE tires unless there are vehicle manufacturer approved options.

Note: Going up with a load range (LRD to LRE) has nothing to do with a tire's designated size. Both load ranges will provide identical load capacities at 65 PSI.

Good info!

But, aside from all of the regulations, and to all who ask "who cares?" - I like that you have properly described this as a "safety violation". Going way up in tire size and capacity can actually make one less safe, not more safe. And, that is why the regulations exist. But that is not the whole story...

I will add to the load range discussion... it is not as simple as just comparing the Load Ranges, like "D" (LRD) or "G" (LRG), etc. In fact there are lots of load ratings within each broad category. These are the 3 digit numbers often called "load indexes" that have a corresponding weight rating. For example, a load index of 125 will always have a capacity of 3640 lbs, regardless of whether the tire has a load range of "D" or an "E" or "F", etc. You are correct in saying that if a tire has the same load index number, it will use the same tire pressure and the carrying capacity will be the same.

BUT, there can be a lot of variance within load ranges. For example, some LRE tires could have a load index as low as 119 (3000lbs). Yet some LRD tires could have a load index as high as 124 (3525lbs). IOW, in the above examples, it is possible to have a "D" tire with more carrying capacity than an "E" tire. (similar with "F" and "G" ranges, although they tend to have a narrower spread)
So, where load ranges like "E" or "G" mostly refer to the number of plys of construction (more related to stiffness), the 3 digit load index narrows it down to what carrying capacity the tire actually is rated for.

In the case of the OEM tires that the OP discussed, I "think" they are load index of 124 (3525lbs) but I don't know for sure what brand came with his rig.
So to go to the Sailun "80's" is likely an upgrade, as the Sailun G637 in size ST235/80R16 has a load index of 129 or 4080lbs. The "85's" have a load index of 132 or 4400lbs.

Regulations aside, where might a practical safety issue come in? If the original rim has a load index much lower than the new tire, you could create a safety issue due to differences in max inflation. The real key is that with the G rated tires, you will be running a tire that needs 110psi in order to achieve its load index. It is critical to make sure that your RIMS are rated for 110psi, or you could definitely cause a safety issue. Rims rated for 85psi can and have failed if tires inflated to 110psi are installed.

So, to the OP, if you are using your original rims, I think it is very important to make sure that your rims are rated for 110psi, and ideally have a load index of 129 or higher. Look at the back of the rims to confirm. Your rims may be fine, but if not, make sure to buy new rims with those new tires.

As to whether to go to the G rated tires in the 80's profile vs the 85's? It's your choice, but the 85's will have no practical increase in carrying capacity, because both greatly exceed the axle rating. And both would technically be a safety violation. The only practical difference is that the 85's have a bit more tread depth to start with, so could potentially last a bit longer. But, for the weight they are hauling, the longevity will likely depend more on proper inflation than the difference in tread.

hth!
Brad

[CalandLinda]

Originally Posted by kowbra

Good info!

But, aside from all of the regulations, and to all who ask "who cares?" - I like that you have properly described this as a "safety violation". Going way up in tire size and capacity can actually make one less safe, not more safe. And, that is why the regulations exist. But that is not the whole story...

I will add to the load range discussion... it is not as simple as just comparing the Load Ranges, like "D" (LRD) or "G" (LRG), etc. In fact there are lots of load ratings within each broad category. These are the 3 digit numbers often called "load indexes" that have a corresponding weight rating. For example, a load index of 125 will always have a capacity of 3640 lbs, regardless of whether the tire has a load range of "D" or an "E" or "F", etc. You are correct in saying that if a tire has the same load index number, it will use the same tire pressure and the carrying capacity will be the same.

BUT, there can be a lot of variance within load ranges. For example, some LRE tires could have a load index as low as 119 (3000lbs). Yet some LRD tires could have a load index as high as 124 (3525lbs). IOW, in the above examples, it is possible to have a "D" tire with more carrying capacity than an "E" tire. (similar with "F" and "G" ranges, although they tend to have a narrower spread)
So, where load ranges like "E" or "G" mostly refer to the number of plys of construction (more related to stiffness), the 3 digit load index narrows it down to what carrying capacity the tire actually is rated for.

In the case of the OEM tires that the OP discussed, I "think" they are load index of 124 (3525lbs) but I don't know for sure what brand came with his rig.
So to go to the Sailun "80's" is likely an upgrade, as the Sailun G637 in size ST235/80R16 has a load index of 129 or 4080lbs. The "85's" have a load index of 132 or 4400lbs.

Regulations aside, where might a practical safety issue come in? If the original rim has a load index much lower than the new tire, you could create a safety issue due to differences in max inflation. The real key is that with the G rated tires, you will be running a tire that needs 110psi in order to achieve its load index. It is critical to make sure that your RIMS are rated for 110psi, or you could definitely cause a safety issue. Rims rated for 85psi can and have failed if tires inflated to 110psi are installed.

So, to the OP, if you are using your original rims, I think it is very important to make sure that your rims are rated for 110psi, and ideally have a load index of 129 or higher. Look at the back of the rims to confirm. Your rims may be fine, but if not, make sure to buy new rims with those new tires.

As to whether to go to the G rated tires in the 80's profile vs the 85's? It's your choice, but the 85's will have no practical increase in carrying capacity, because both greatly exceed the axle rating. And both would technically be a safety violation. The only practical difference is that the 85's have a bit more tread depth to start with, so could potentially last a bit longer. But, for the weight they are hauling, the longevity will likely depend more on proper inflation than the difference in tread.

hth!
Brad

Load index numbers are not the official load indicator for ST & LT tires, load range letters are. The primary reason for the load index numbers to be found on ST & LT tires is because its the official way to display a tire speed rating letter, its found on the end of a load index number.

Again, a designated size ST235/80R16 LRE is the same specification size as a LRG.

It is the tire manufacturer's responsibility to insure the tire in hand is fitted to the proper wheel/rim size. It's the wheel manufacturer's responsibility to provide individual rim specifications on request.

Load index number 132 = 4409#.

[kowbra]

Originally Posted by CalandLinda

Load index numbers are not the official load indicator for ST & LT tires, load range letters are. The primary reason for the load index numbers to be found on ST & LT tires is because its the official way to display a tire speed rating letter, its found on the end of a load index number.

Again, a designated size ST235/80R16 LRE is the same specification size as a LRG.

It is the tire manufacturer's responsibility to insure the tire in hand is fitted to the proper wheel/rim size. It's the wheel manufacturer's responsibility to provide individual rim specifications on request.

Load index number 132 = 4409#.

Edit: I do see a load index rating for Goodyear Endurance E rated trailer tires; in the size above, the load index is 123 and the weight rating is 3420lbs at 80psi inflation.
Which is VERY different than the same size Sailun G rated, at 4080lbs and 110psi.
There is definitely a huge difference in load carrying, and max inflation.
So, can you please clear this up? I think I am even more confused now...

Brad

[kowbra]

Originally Posted by CalandLinda

Load index numbers are not the official load indicator for ST & LT tires, load range letters are. The primary reason for the load index numbers to be found on ST & LT tires is because its the official way to display a tire speed rating letter, its found on the end of a load index number.

Again, a designated size ST235/80R16 LRE is the same specification size as a LRG.

It is the tire manufacturer's responsibility to insure the tire in hand is fitted to the proper wheel/rim size. It's the wheel manufacturer's responsibility to provide individual rim specifications on request.

Load index number 132 = 4409#.

So, I had to look this up... this from Tirerack blog...

"When looking at light truck (LT) or newer Special Trailer Service (ST) tires, there are two load indexes branded on the sidewall, separated by a forward slash. Using an LT235/75R15 104/101S Load Range C tire as an example, the load index is 104/101. 104 corresponds to 1,984 pounds, and 101 corresponds to 1,819 pounds. So what is the true load carrying capacity of the tire? The answer changes depending on the situation in which the tire is being used."

EDIT: removed the paragraph about dual wheels.
EDIT2: (added for clarity) - the above is not an example discussing the sizes in question in this thread. Rather it is shared to show that LT and ST tires do use a load index rating that maps to carrying capacity, as discussed previously.

---

Cal, please help me understand what you mean.

Thanks,
Brad

[kowbra]

And, BTW, so as to not confuse the potential issue for the OP here, because I think there has been a lot of extraneous information...

Here is the most critical thing - if you have a rim rated for 80psi and install G rated tires then inflate to 110psi, you will be creating an unsafe combination.

Please check your rims to make sure you are ok to go to G rated tires. Your tire shop should check this, but you might get the kid that started last week.

Brad

[sourdough]

IMO we may be getting into the "weeds" here. Load ranges are an accepted standard of weight for a tire. We all know them, look at them etc. The numbers also correlate to a weight BUT the load range is what we all look at and they are definitive.

Trying to parse/find something to argue over a 100lb rating on a tire just seems to tell me that one is too near "the edge". Cal can speak to lots of "stuff" but he knows of what he speaks IMO.

[kowbra]

Originally Posted by sourdough

IMO we may be getting into the "weeds" here. Load ranges are an accepted standard of weight for a tire. We all know them, look at them etc. The numbers also correlate to a weight BUT the load range is what we all look at and they are definitive.

Trying to parse/find something to argue over a 100lb rating on a tire just seems to tell me that one is too near "the edge". Cal can speak to lots of "stuff" but he knows of what he speaks IMO.

Ok, just to be clear, I'm not saying Cal is wrong, nor am I saying you are. I'm trying to make sure I understand.

I think you may have misunderstood what I shared from tirerack. It was copied from their blog; I did not share because I thought the examples they used were what we were discussing, because they are not. But the point was that they confirm that LT and ST tires DO use a load index rating, much as I described.

When you apply that load index to the tires in the question from the OP, there is a lot more than a 100lbs difference. I think the OP is going from about a 3500lbs capacity tire at 80psi to as much as a 4400lbs tire at 110psi. I believe that difference matters, so to me is that not getting into the weeds.

I hope that makes sense, and I'd be curious to see what Cal says when he can weigh in again.

Brad

[CalandLinda]

Originally Posted by kowbra

Ok, just to be clear, I'm not saying Cal is wrong, nor am I saying you are. I'm trying to make sure I understand.

I think you may have misunderstood what I shared from tirerack. It was copied from their blog; I did not share because I thought the examples they used were what we were discussing, because they are not. But the point was that they confirm that LT and ST tires DO use a load index rating, much as I described.

When you apply that load index to the tires in the question from the OP, there is a lot more than a 100lbs difference. I think the OP is going from about a 3500lbs capacity tire at 80psi to as much as a 4400lbs tire at 110psi. I believe that difference matters, so to me is that not getting into the weeds.

I hope that makes sense, and I'd be curious to see what Cal says when he can weigh in again.

Brad

I read a lot of things about tires that are somewhat bewildering to normal every day users.

With that all said let's look at some facts.

A tire's designated size may best be described as being the correct nomenclature for that particular tire. However, tires are loaded with sidewall information that does not relate to its size designation. It is probably best described in the following USTMA manual.

https://www.ustires.org/sites/defaul...%2029%2018.pdf

In the NHTSA rules committee meeting of 2007 the load range lettering system was established as the official medium for determining ST & LT tire inflation values. It was not mentioned in the 2010 so it remained the same. The Tire and Rim Association (TRA) are responsible for standardizing the load inflation charts for all of those tires.

About three years ago our federal government gave the off shore tire manufactures (mostly Chinese) of ST tires – and others – a mandate to provide speed ratings for ST tires or pay higher tariffs. The instructions they were given was to use the established method of using a load index number followed by the speed rating letter, or mold a speed rating into the tire sidewall. Because there is no speed letter for 65 MPH most that complied with the ultimatum increased the ST tire rating to the letter “L” = 75 MPH or higher. Without a speed rating on the tire the TRA rates them at 65 MPH, with no exceptions.

When we look at tire fitment regulations we must also look at their certification process in 49 CFR part 567. RV trailers are built under the guidance of FMVSS (standards). Those standards provide mandatory compliance with minimum standards. Looking at your trailer’s certification label you’ll find the Original Equipment tire designated size and the appropriate cold inflation pressure for that fitment. That information is minimum and must be maintained. Says who? FMVSS 571.120, paragraph S 5.3.1.

Your RV tires are fitted to your trailer by designated size and load capacity. The designated size is just that, the name of the tire. Its load capacity is set with inflation pressure. The maximum amount of inflation pressure will be determined by the tires load range letter. Because ST tires all comply with standardized load inflation charts, a designated size with a load range “D” will provide an identical load capacity as a load range “E” at 65 PSI. The tire designated size does not change because of a higher or lower load range letter.

Verbatim from USTMA manual: “Tire Replacements; Replacement tires should be the same as the OE size designation, or approved options, as recommended by the vehicle or tire manufacturer. Never choose a replacement tire of a smaller size or with less load-carrying capacity than the OE tire size at the specified vehicle tire placard pressure.”

Personally I went from a LRD to a LRE with the same designated size. The “should be” is in reference to brand names which are never mentioned in regulations or standards.

NHTSA has a link where a consumer can ask for interpretations. I asked for one on tire industry standards and received this response.

“Industry Standards generally form the basis for determining product safety and quality before courts, regulators, retailers, consumers and others”

[phillyg]

Just to be clear, the OP asked about changing out his tires in the same size, "......The tires are ST235/80R 16F (12 ply).
Looking to upgrade......Sailun ST 235/80R 16 G9 Rated/14ply (all steel)......Or......Hercules ST235/80R 16 H-901 (G rate/14 ply all steel)......" but then he asked the question that set fire to the keyboards about safety violations, deviations and wheel capacity, etc., "could I put 85Rs on the 295RL model?"

OP, I missed that your current tires are F-rated, so their max is 95psi, right? Calandlinda reminded us your wheels must be rated to 110psi. They should be, but you must make sure if you go G-rated. It appears Sailuns or Hercules in the same size will work for you, and Sailun has a great rep. After weighing your trailer use the appropriate psi from the Sailun load table; it shouldn't be more that 95psi. Lastly, while you could go to 85s, I don't see the need since you only had F-rated tires to begin with.

[CalandLinda]

USTMA quote:

"Inflation pressure recommendations may also be determined based on the tire manufacturer’s specifications, which define the amount of inflation pressure necessary to carry a given load. These inflation pressures may differ from those found on the vehicle tire placard or certification label. However, never use inflation pressures lower than specified by the vehicle tire placard, certification label or owner’s manual. Nor should inflation pressure exceed the maximum pressure molded on the tire sidewall."

[kowbra]

Originally Posted by CalandLinda

I read a lot of things about tires that are somewhat bewildering to normal every day users.

With that all said let's look at some facts.

...

Personally I went from a LRD to a LRE with the same designated size. The “should be” is in reference to brand names which are never mentioned in regulations or standards.

NHTSA has a link where a consumer can ask for interpretations. I asked for one on tire industry standards and received this response.

“Industry Standards generally form the basis for determining product safety and quality before courts, regulators, retailers, consumers and others”

Thanks Cal, very informative!

Let me see if I can sum up from my layman's view... tires of the same size, inflated to the same pressure, will carry the same load, regardless of load range rating.

If so, then perhaps the greatest concern for the average person (and even a lot of the paid "professionals"), is that tires of a higher load range will likely be inflated to the rating on the sidewall, resulting in more pressure than the OEM designed. The result could be rim failure.

Do I understand this correctly?

Thanks again for the good info; I will "chew" through the PDF you linked when I have time

Brad

[CalandLinda]

Originally Posted by kowbra

Thanks Cal, very informative!

Let me see if I can sum up from my layman's view... tires of the same size, inflated to the same pressure, will carry the same load, regardless of load range rating.

If so, then perhaps the greatest concern for the average person (and even a lot of the paid "professionals"), is that tires of a higher load range will likely be inflated to the rating on the sidewall, resulting in more pressure than the OEM designed. The result could be rim failure.

Do I understand this correctly?

Thanks again for the good info; I will "chew" through the PDF you linked when I have time

Brad

Well trained professional tire installers will always insure the tire and wheel are compatible with each other. The do-it-yourselfers must make an effort to insure tires with a higher load range or size different from the OE tires are fitted to wheels/rims that will support the desired load and inflation pressures, when applicable.

One of the set-backs consumers face with todays RV trailers is the abundance of tires with numerous load ranges. Tire/wheel OEM providers will marry them to their individual specifications. An example is found with the LRF 16" wheel/tire assembly. The standard wheel/rim used by OEM providers for a combination of the ST235/85R16 LRF will almost always use a wheel rated for 3960# at 95 PSI. Many consumers will install LRG tires on those rims. Everything is okay as long as the inflation pressures provide 3960# of load capacity. When they decide to use the 110 PSI for the maximum load of a replacement LRG tire they are exceeding the wheel/rim capacities. It can only be described as an UNSAFE procedure.

https://www.lionsheadtireandwheel.co...Aluminum-Wheel

[sourdough]

Originally Posted by kowbra

Thanks Cal, very informative!

Let me see if I can sum up from my layman's view... tires of the same size, inflated to the same pressure, will carry the same load, regardless of load range rating.

If so, then perhaps the greatest concern for the average person (and even a lot of the paid "professionals"), is that tires of a higher load range will likely be inflated to the rating on the sidewall, resulting in more pressure than the OEM designed. The result could be rim failure.

Do I understand this correctly?

Thanks again for the good info; I will "chew" through the PDF you linked when I have time

Brad

Brad before upsizing the load range of a tire always inspect the wheels for their max pressure/load. It should be (maybe) stamped on the back of them.

[PSFORD99]

Originally Posted by CalandLinda

Well trained professional tire installers will always insure the tire and wheel are compatible with each other. The do-it-yourselfers must make an effort to insure tires with a higher load range or size different from the OE tires are fitted to wheels/rims that will support the desired load and inflation pressures, when applicable.

One of the set-backs consumers face with todays RV trailers is the abundance of tires with numerous load ranges. Tire/wheel OEM providers will marry them to their individual specifications. An example is found with the LRF 16" wheel/tire assembly. The standard wheel/rim used by OEM providers for a combination of the ST235/85R16 LRF will almost always use a wheel rated for 3960# at 95 PSI. Many consumers will install LRG tires on those rims. Everything is okay as long as the inflation pressures provide 3960# of load capacity. When they decide to use the 110 PSI for the maximum load of a replacement LRG tire they are exceeding the wheel/rim capacities. It can only be described as an UNSAFE procedure.

https://www.lionsheadtireandwheel.co...Aluminum-Wheel

I see you referenced some wheels ,where is it saying those wheels @ 3960 are only rated for 95 psi.

Wasn't it not long ago ,our Montana wheels were rated for 3750 , and 110 psi, possibly still are ??