Tires and fifth wheel hitches - RV-Dreams Community Forum

CraigAs · RV-Dreams Community Member

Tires and fifth wheel hitches

Howard · Host

Hey Craig,

Well, there is a ton of tire information on this Forum, so I'm surprised you haven't found it.

Anyway, many of us that have towed heavy fifth wheels highly recommend the Goodyear G114 17.5-inch tires 215/75R17/5 with the load range "H" (max capacity is 4805 pounds) - it's a commercial tire. For lighter fifth wheels the Goodyear G614s (16-inch; LT235/85R16 load range "G" light truck tire) are solid (max capacity 3750 pounds), but I wouldn't push them to their limits. The G114s are a good retrofit for the G614s as they are very close (millimeters) in diameter IF you are willing to change out the rims.

In other words, much depends on the weight you will be carrying on your axles. There are many other cheaper options out there and you will find lots of opinions, but most people will advise you to avoid tires made in China by Chinese companies that have American sounding names.

Also, many fifth wheels come with ST (special trailer) tires with lower load ranges (usually load range "E") and those are often pushed to their limits on weight and speed (almost all ST tires are only rated for 65 mph). Even the Goodyear Marathons (ST tires) have had issues when folks load them to their limits or overload them and/or drive too fast on them. ST tires aren't inherently bad for fifth wheels, they just need to be on the lighter weight models.

It all comes down to making sure you have the proper tire with plenty of safety margin for the load you are (or will be) carrying. The best tires aren't cheap, and if they aren't properly maintained, even they will fail prematurely.

As for the puck mounting system, I just don't know that much about them. I'm sure others will chime in on that.

However, for your situation, I would consider the Anderson Ultimate as a good way to go. I've seen these in action, and I think it's a great option for those wanting a clean truck bed when not towing their fifth wheel. Check it out.

Bill and Linda · RV-Dreams Family Member

When one looks at the cost of a G114 tire take into consideration how long the tire will last even ignoring the fact they won't (well anything can) blow out like most RV type tires such as the G614.

Do the math on the cost of the "H" tires vs. mileage. I currently have a set with a logged 61,591 miles on them. Still within tread spec and I plan to run at least another 6,500 miles going from Canada via NC to West Yellowstone to Phoenix and back to NC this fall. This set has been from Alaska to Newfoundland, along with several trips around the US without a tire issue of any kind.

On mileage alone they pay for themselves. Many will run out of "years" before they run out of tread. That's a nice situation to have.

Naturally, YMMV. (Had to type that. :) )

Bill

Second Chance · RV-Dreams Family Member

I would also throw the Sailun ST tires into the ring. Highly regarded by a lot of RVers and good safety/reliability record. A lot of trucking companies use their commercial line on 18-wheelers.

Rob

Bill and Linda · RV-Dreams Family Member

Second Chance wrote:
I would also throw the Sailun ST tires into the ring. Highly regarded by a lot of RVers and good safety/reliability record. A lot of trucking companies use their commercial line on 18-wheelers.

Rob

Operative word is "Commercial." The Goodyear G114 "H" tire is a commercial tire. The Goodyear G614 is not. "I" sometimes refer to the G614, as an example, as an "RV Grade" tire.

I'm really saying it is the "commercial" grade of the tires that is really making the difference in both design and durability - especially in the side walls which is where the blow outs many times occur.

My opinions.

FastEagle · RV-Dreams Family Member

"Off Shore" trailer tire manufacturers are constantly upgrading their products. As the RV trailers have evolved into larger and heavier models, the tire industry has also increased their manufacturing capabilities. They have added numerous new sizes with load capacities for all needs.

The smaller 13” & 14” tires now have more than one load range in popular sizes that meet the needs of axles they are fitted to. Those needs grew dramatically when RVIA recommended a minimum 10% load capacity reserve for all RV trailer tire fitments. They also recommended that only radial ply tires be used on all RV trailer tires 14” and above.

Steel cased 16” tires are being built by just about all of the known name brands. The popular sizes are ST235/80R16 LRG with a maximum load capacity of 4080# and the ST235/85R16 LRG with a maximum load capacity of 4400#.

There is a single steel cased 15” tire already at USA retailers. It’s the ST225/75R15 LRF with a maximum load capacity of 3195#.

When GY got their redesigned Endurance tires on the market they also introduced a new size. It’s the ST255/85R16 LRE with a maximum load capacity of 4080# @ 80 PSI.

Just about all of the new ST tires have speed letters above the “K” rating, (68 MPH). Most are L or M with some of the smaller ones at N. 13” bias ply tires are usually J = 62 MPH. Any found without a speed rating marked on their sidewall default to the industry standard of 65 MPH.

If you’re a high mileage user you should seriously consider the commercial low platform trailer tires. The specs for 17.5 OD tires are usually very compatible for height and width requirements. Some are European designed. Those will have a speed letter “J” = 62 MPG. Almost all of the others will be about 75 MPH. Because of their durability, construction and high mileage capabilities they tend to double the life expectancy of an ST tire with equal load capacity. Don’t be sucked into inflating them to the load carried. Most of the larger RV trailers they work well on only have 4 tires. The RV trailer will bob and weave much more dramatically than the low platform trailers they are designed for. Follow the RVIA 10% load capacity reserve recommendation.

arcaguy · RV-Dreams Family Member

FastEagle wrote:
Don’t be sucked into inflating them to the load carried.

I'm confused. Is this what you intended to say? Normally you always inflate tires to the load carried. If you under inflate them you build heat and wear the outside edges. If you over inflate them you wear the center but don't build heat. In both cases you wear your tires out faster than a properly inflated tire. I agree that you should not inflate them to the maximum sidewall spec but I don't agree that you should not inflate them to the load carried, that is exactly what you should do. I'm pretty sure this supports what I am saying https://www.goodyearrvtires.com/pdfs/tire-care-guide.pdf.

FastEagle · RV-Dreams Family Member

arcaguy wrote:
FastEagle wrote:
Don’t be sucked into inflating them to the load carried.
I'm confused. Is this what you intended to say? Normally you always inflate tires to the load carried. If you under inflate them you build heat and wear the outside edges. If you over inflate them you wear the center but don't build heat. In both cases you wear your tires out faster than a properly inflated tire. I agree that you should not inflate them to the maximum sidewall spec but I don't agree that you should not inflate them to the load carried, that is exactly what you should do. I'm pretty sure this supports what I am saying https://www.goodyearrvtires.com/pdfs/tire-care-guide.pdf.

Inflating tires to the load carried is a spin-off from the Federal Motor Carrier Safety Administration tire regulations. Those regulations are not applicable to vehicles manufactured under the guidance of the Federal Motor Vehicle Safety Standards. When a final stage manufacturer certifies the whole vehicle in accordance with FMVSS it includes the OE tires no matter what design.

Under the FMVSS, the recommended cold inflation pressures displayed for the original tires fitted to the vehicle are the correct inflation pressures. Inflation pressures between recommended and tire sidewall inflation pressures are optional.

Because of the higher than normal tire failure rate for RV trailers RVIA has stepped-in with a recommendation for vehicle manufacturers to provide a minimum of 10% in tire load capacity reserves above the trailers certified GAWRs. That would also preclude inflating RV trailer tires to the load carried. (The existing standards for RV trailer tire fitments do not provide load capacity reserves). A RV trailer manufacturer can fit a trailer with 7000# axles, derate them to 6840#, certify that as the GAWR and then fit two tires rated at 3420# to those axles. Legal, and has been documented many times with numerous tire sizes and load capacities. About the time a trailer fitted like that reaches it’s maximum cargo load, POP goes the tires.

The following is an excerpt from the U.S. Tire Manufacturers Association.

“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 pressure 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.”

-- Edited by FastEagle on Monday 13th of August 2018 03:05:19 PM

-- Edited by FastEagle on Monday 13th of August 2018 03:08:24 PM

-- Edited by FastEagle on Monday 13th of August 2018 03:12:57 PM

Bill and Linda · RV-Dreams Family Member

FastEagle wrote:
arcaguy wrote:
FastEagle wrote:
Don’t be sucked into inflating them to the load carried.
I'm confused. Is this what you intended to say? Normally you always inflate tires to the load carried. If you under inflate them you build heat and wear the outside edges. If you over inflate them you wear the center but don't build heat. In both cases you wear your tires out faster than a properly inflated tire. I agree that you should not inflate them to the maximum sidewall spec but I don't agree that you should not inflate them to the load carried, that is exactly what you should do. I'm pretty sure this supports what I am saying https://www.goodyearrvtires.com/pdfs/tire-care-guide.pdf.
Inflating tires to the load carried is a spin-off from the Federal Motor Carrier Safety Administration tire regulations. Those regulations are not applicable to vehicles manufactured under the guidance of the Federal Motor Vehicle Safety Standards. When a final stage manufacturer certifies the whole vehicle in accordance with FMVSS it includes the OE tires no matter what design.
Under the FMVSS, the recommended cold inflation pressures displayed for the original tires fitted to the vehicle are the correct inflation pressures. Inflation pressures between recommended and tire sidewall inflation pressures are optional.
Because of the higher than normal tire failure rate for RV trailers RVIA has stepped-in with a recommendation for vehicle manufacturers to provide a minimum of 10% in tire load capacity reserves above the trailers certified GAWRs. That would also preclude inflating RV trailer tires to the load carried. (The existing standards for RV trailer tire fitments do not provide load capacity reserves). A RV trailer manufacturer can fit a trailer with 7000# axles, derate them to 6840#, certify that as the GAWR and then fit two tires rated at 3420# to those axles. Legal, and has been documented many times with numerous tire sizes and load capacities. About the time a trailer fitted like that reaches it’s maximum cargo load, POP goes the tires.
The following is an excerpt from the U.S. Tire Manufacturers Association.
“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.”

So, I'm still confused. Actually I'm not. I have tire X on my RV. I was supplied an inflation chart provided by the manufacture for those OEM supplied tires. It says I should inflate my tires to a PSI based on the "known" - known by calibrated scales on a wheel-by-wheel basis - inflation based on those known, certified weights. (Heaviest tire determining PSI for all tires.) That inflation is less than then the maximum inflation on the side of the tire. Are you saying the tire manufacture's recommendations are wrong and we should do otherwise and ignore the tire manufacture's charts? That's what I read in this and other posts.

Rickl · RV-Dreams Family Member

The reasons most manufacturers state to inflate to max PSI (for trailer applications) and why the RVIA says to increase the pressure to provide a 10% cushion is simply this - the VAST majority of people do NOT properly know their weights and/or maintain tire pressures.

In the 90’s Goodyear absolutely recommended inflating the trailer tires to the amount of load based on the highest load. However as things evolved and it became apparent people didn’t weigh their loads or maintain tire pressures the recommendation changed to max inflation.

Having been in the tire industry for 35+ years with experience across the spectrum of usage, tire pressures are the key. The container handlers are so sensitive that a 2 lb difference along with speed can mean thousands of dollars if not maintained. We are talking speeds in the 1.5 to 2 miles a hour. The weight they haul, much like mining trucks, is phenomenal.

In my opinion the bottom line is this, correct tire for the application, inflated to the correct weight and maintained, and speed being watched will provide anyone with exceptional wear.

FastEagle · RV-Dreams Family Member

Rickl wrote:
The reasons most manufacturers state to inflate to max PSI (for trailer applications) and why the RVIA says to increase the pressure to provide a 10% cushion is simply this - the VAST majority of people do NOT properly know their weights and/or maintain tire pressures.

In the 90’s Goodyear absolutely recommended inflating the trailer tires to the amount of load based on the highest load. However as things evolved and it became apparent people didn’t weigh their loads or maintain tire pressures the recommendation changed to max inflation.

Having been in the tire industry for 35+ years with experience across the spectrum of usage, tire pressures are the key. The container handlers are so sensitive that a 2 lb difference along with speed can mean thousands of dollars if not maintained. We are talking speeds in the 1.5 to 2 miles a hour. The weight they haul, much like mining trucks, is phenomenal.
(Their inflation pressures are determined by a completely different set of regulations. The Federal Motor Vehicle Safety Administration. Those regulations are not applicable with FMVSS).

In my opinion the bottom line is this, correct tire for the application, inflated to the correct weight and maintained, and speed being watched will provide anyone with exceptional wear.

The real bottom line: Vehicle manufacturer's have the sole responsibility for setting baseline tire inflation pressures. In fact, in FMVSS 571.120 paragraph 10 the vehicle manufacturer is directed to set tire inflation pressures that are appropriate for the OE tires and then display those inflation pressures on the vehicle certification label. Any tire manufacturer complying with FMVSS is not going to infringe on the vehicle manufacturers Recommended Cold Inflation pressures for OE tires.

Before you jump on me about plus sized tires I'll insert this tire industry standard. Replacement tires must provide a load capacity equal to the OE tires via inflation. This is where tire inflation charts are very necessary.

In one of my earlier posts in this thread I mentioned optional inflation pressures. Those do not infringe upon the vehicle manufacturers recommendations for OE tires because they start at that level and work all the way to the minimum pressure on the tire sidewall for the maximum load capacity of the tire.

In threads about tire inflation pressures, a curious situation presents itself. Load capacity reserves. All of our automotive tires have it. Just look at your tire placard and do some math. Do you not wonder what would happen if you were to set your Car's tire inflation level to the load carried?

-- Edited by FastEagle on Tuesday 14th of August 2018 07:48:11 AM

FastEagle · RV-Dreams Family Member

Bill and Linda wrote:
FastEagle wrote:
arcaguy wrote:
FastEagle wrote:
Don’t be sucked into inflating them to the load carried.
I'm confused. Is this what you intended to say? Normally you always inflate tires to the load carried. If you under inflate them you build heat and wear the outside edges. If you over inflate them you wear the center but don't build heat. In both cases you wear your tires out faster than a properly inflated tire. I agree that you should not inflate them to the maximum sidewall spec but I don't agree that you should not inflate them to the load carried, that is exactly what you should do. I'm pretty sure this supports what I am saying https://www.goodyearrvtires.com/pdfs/tire-care-guide.pdf.
Inflating tires to the load carried is a spin-off from the Federal Motor Carrier Safety Administration tire regulations. Those regulations are not applicable to vehicles manufactured under the guidance of the Federal Motor Vehicle Safety Standards. When a final stage manufacturer certifies the whole vehicle in accordance with FMVSS it includes the OE tires no matter what design.
Under the FMVSS, the recommended cold inflation pressures displayed for the original tires fitted to the vehicle are the correct inflation pressures. Inflation pressures between recommended and tire sidewall inflation pressures are optional.
Because of the higher than normal tire failure rate for RV trailers RVIA has stepped-in with a recommendation for vehicle manufacturers to provide a minimum of 10% in tire load capacity reserves above the trailers certified GAWRs. That would also preclude inflating RV trailer tires to the load carried. (The existing standards for RV trailer tire fitments do not provide load capacity reserves). A RV trailer manufacturer can fit a trailer with 7000# axles, derate them to 6840#, certify that as the GAWR and then fit two tires rated at 3420# to those axles. Legal, and has been documented many times with numerous tire sizes and load capacities. About the time a trailer fitted like that reaches it’s maximum cargo load, POP goes the tires.
The following is an excerpt from the U.S. Tire Manufacturers Association.
“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.”

So, I'm still confused. Actually I'm not. I have tire X on my RV. I was supplied an inflation chart provided by the manufacture for those OEM supplied tires. It says I should inflate my tires to a PSI based on the "known" - known by calibrated scales on a wheel-by-wheel basis - inflation based on those known, certified weights. (Heaviest tire determining PSI for all tires.) That inflation is less than then the maximum inflation on the side of the tire. Are you saying the tire manufacture's recommendations are wrong and we should do otherwise and ignore the tire manufacture's charts? That's what I read in this and other posts.

It's my guess that your "tire X" is a commercial tire. When tires are fitted to RV trailers they are done so under the guidance of FMVSS. Regardless of design they are all fitted and serviced as trailer tires. Tire manufacturers NO NOT set vehicle recommended cold inflation pressures. They do provide the vehicle manufacturers with charts designed to determine the correct inflation pressures needed for each vehicle manufacturer fitment of OE tires. However, RV trailer manufacturers seldom reefer to inflation charts because of the different fitment standard for OE tires. On RV trailers there are no standards requiring load capacity reserves. Almost all RV trailer manufacturer's select tires with marginal load capacities and then set the recommended cold inflation pressures at a PSI value to provide maximum load capacity from the tires. There is no wiggle room. It's important to remember that the inflation pressures depicted on a ST or LT tire's sidewall is not it's maximum allowable inflation pressure. That PSI value on the sidewall is the amount of inflation needed for the tire to provide its full load capacity.

-- Edited by FastEagle on Tuesday 14th of August 2018 08:13:35 AM

Bill and Linda · RV-Dreams Family Member

FastEagle wrote:
Bill and Linda wrote:
FastEagle wrote:
arcaguy wrote:
FastEagle wrote:
Don’t be sucked into inflating them to the load carried.
{Edit}
The following is an excerpt from the U.S. Tire Manufacturers Association.
“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.”

So, I'm still confused. Actually I'm not. I have tire X on my RV. I was supplied an inflation chart provided by the manufacture for those OEM supplied tires. It says I should inflate my tires to a PSI based on the "known" - known by calibrated scales on a wheel-by-wheel basis - inflation based on those known, certified weights. (Heaviest tire determining PSI for all tires.) That inflation is less than then the maximum inflation on the side of the tire. Are you saying the tire manufacture's recommendations are wrong and we should do otherwise and ignore the tire manufacture's charts? That's what I read in this and other posts.
It's my guess that your "tire X" is a commercial tire. When tires are fitted to RV trailers they are done so under the guidance of FMVSS. Regardless of design they are all fitted and serviced as trailer tires. Tire manufacturers NO NOT set vehicle recommended cold inflation pressures. They do provide the vehicle manufacturers with charts designed to determine the correct inflation pressures needed for each vehicle manufacturer fitment of OE tires. However, RV trailer manufacturers seldom reefer to inflation charts because of the different fitment standard for OE tires. On RV trailers there are no standards requiring load capacity reserves. Almost all RV trailer manufacturer's select tires with marginal load capacities and then set the recommended cold inflation pressures at a PSI value to provide maximum load capacity from the tires. There is no wiggle room. It's important to remember that the inflation pressures depicted on a ST or LT tire's sidewall is not it's maximum allowable inflation pressure. That PSI value on the sidewall is the amount of inflation needed for the tire to provide its full load capacity.

-- Edited by FastEagle on Tuesday 14th of August 2018 08:13:35 AM

Now with that important clarification we're on the same page. Indeed, most "RV" grade tires (my term but Goodyear uses the term "RV Tire" as well) are running at or very near there rated capacity. And indeed, the sidewalls are many times the issue. Many RV's on "G" or less tires, (generalization) are pushing the limit if not overloading at least one tire if the trailer is used for full timing.

My comment was to clarify that most, but not all, of the time RV's should be run at the maximum inflation for the reasons you stated. That's an important detail. But there is a "it depends" that needs to be added as many on this site are running commercial tires which are provided by the OEM and they indeed, in many cases, are over rated beyond the wheel and axle limits / load and quite a bit in fact over rated if run a max psi. Hence the tire OEM recommendations as to load are totally applicable and should be followed, in my opinion, if one knows the weights on the wheels and uses the measured max wheel weight as the determining PSI as I commented.

Maybe Howard will jump in with his 2 cents considering he dealt with tires, pressures and weighting for quite sometime.

FastEagle · RV-Dreams Family Member

Bill and Linda wrote:
FastEagle wrote:
Bill and Linda wrote:
FastEagle wrote:
arcaguy wrote:
FastEagle wrote:
Don’t be sucked into inflating them to the load carried.
{Edit}
The following is an excerpt from the U.S. Tire Manufacturers Association.
“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.”

So, I'm still confused. Actually I'm not. I have tire X on my RV. I was supplied an inflation chart provided by the manufacture for those OEM supplied tires. It says I should inflate my tires to a PSI based on the "known" - known by calibrated scales on a wheel-by-wheel basis - inflation based on those known, certified weights. (Heaviest tire determining PSI for all tires.) That inflation is less than then the maximum inflation on the side of the tire. Are you saying the tire manufacture's recommendations are wrong and we should do otherwise and ignore the tire manufacture's charts? That's what I read in this and other posts.
It's my guess that your "tire X" is a commercial tire. When tires are fitted to RV trailers they are done so under the guidance of FMVSS. Regardless of design they are all fitted and serviced as trailer tires. Tire manufacturers NO NOT set vehicle recommended cold inflation pressures. They do provide the vehicle manufacturers with charts designed to determine the correct inflation pressures needed for each vehicle manufacturer fitment of OE tires. However, RV trailer manufacturers seldom reefer to inflation charts because of the different fitment standard for OE tires. On RV trailers there are no standards requiring load capacity reserves. Almost all RV trailer manufacturer's select tires with marginal load capacities and then set the recommended cold inflation pressures at a PSI value to provide maximum load capacity from the tires. There is no wiggle room. It's important to remember that the inflation pressures depicted on a ST or LT tire's sidewall is not it's maximum allowable inflation pressure. That PSI value on the sidewall is the amount of inflation needed for the tire to provide its full load capacity.

-- Edited by FastEagle on Tuesday 14th of August 2018 08:13:35 AM
Now with that important clarification we're on the same page. Indeed, most "RV" grade tires (my term but Goodyear uses the term "RV Tire" as well) are running at or very near there rated capacity. And indeed, the sidewalls are many times the issue. Many RV's on "G" or less tires, (generalization) are pushing the limit if not overloading at least one tire if the trailer is used for full timing.
My comment was to clarify that most, but not all, of the time RV's should be run at the maximum inflation for the reasons you stated. That's an important detail. But there is a "it depends" that needs to be added as many on this site are running commercial tires which are provided by the OEM and they indeed, in many cases, are over rated beyond the wheel and axle limits / load and quite a bit in fact over rated if run a max psi. Hence the tire OEM recommendations as to load are totally applicable and should be followed, in my opinion, if one knows the weights on the wheels and uses the measured max wheel weight as the determining PSI as I commented.
Maybe Howard will jump in with his 2 cents considering he dealt with tires, pressures and weighting for quite sometime.
(I think I mentioned this earlier. The RV trailer manufacturer has the sole responsibility for selection, fitment and setting the recommended cold inflation pressures for all Original Equipment tires from whatever design they deem appropriate for that vehicle). (Tire manufacturers do not set recommended inflation pressures for any vehicle certified in accordance with FMVSS).

It's a judgement call for the vehicle owner. Vehicles built under the guidance of FMVSS are going to be certified in accordance with CFR 49 Part 567 (Certification). Under that procedere there is always a recommended cold inflation pressure. Without such recommendations there is no safety guidelines to follow. I think if you read chapter #4 of the enclosed reference you may have a better understanding of the safety features of the industry. I often refer to it as being in the playing field. The industries involved with tire safety, operate within the guidelines set by those players in the field. And that's why I started with the judgement call. Once an owner is fully aware of all the safety guidelines set to play in the field, they may find an option to play outside of the field, thus overriding all of the industries expert advise.

https://www.ustires.org/sites/default/files/CareAndService_PassengerAndLightTruckTires.pdf

Chapter #4 addresses RV tires.

-- Edited by FastEagle on Tuesday 14th of August 2018 02:37:34 PM

-- Edited by FastEagle on Tuesday 14th of August 2018 02:38:59 PM