RV Trailer Tires

[CWtheMan]

I spend a few hours every week on ST tire researching. This week it's been TBC Brands.

The Towmax name on ST tires has almost always been viewed as a warning. Here again, you can see the reengineering of China made ST tires is always in progress.

You could bet it wouldn't be long for the China ST market to emulate the GY Endurance ST line-up.

The new Towmax long name is; Power King Towmax Vanguard. The tires will be touted as Towmax Vanguard. For this TBC endeavor I would describe Vanguard as; "a group of people leading the way in new developments or ideas." Actually it looks like sealing to me.

Here is an excerpt from their product introduction pdf. ""The Towmax Vanguard was designed to be the industry standard by combining an array of features to provide consumers a unique quality and performance proposition. The tire features decoupling grooves and an optimized tread depth to reduce rolling resistance and heat buildup extending the life of the tire while large shoulders and an extra wide tread face provide even load distribution and stability through a larger contact patch. The nylon overlays used on all sizes help achieve an 87 mph maximum speed rating and ensure improved towing stability and high speed durability. To maintain the tire’s appearance and decrease sidewall damage, the Towmax Vanguard also features scuff protectors."

[CWtheMan]

Tredit is one of Keystone's major OEM provider of tires. If you explore their web site you'll probably find some brand names you're not familiar with.

But, I'm not posting this in support of any particular brand. However, I'll have to mention a name brand to describe what I think is a very good option for those of you boondocking with tag along trailers. Rainier has a new - about a year now - ST tire design that just may get your interest. It's described in the reference below.

https://www.tredittire.com/tire/rainier-st-apex/

[CWtheMan]

In no way does the use of a tire brand name in my posts constitute anything other than tire industry information. The China ST tire manufacturers are very responsive to the needs and desires of the RV trailer community.

Just about all of the most productive China ST tire manufacturers are now building the popular 16” all steel ST tires in two designated sizes and they are all LRG.

TransEagle – in the link below – has added a 15” all steel ST tire to their line-up. It is the ST225/75R15 and it has two load ranges, LRF & LRG.

http://transeagletires.com/

Carlisle has added the 15” LRF to their all steel ST tire listings (CSL).

https://www.carlislebrandtires.com/o...-detail/csl16/

TowMaster by Greenball have also added the 15” LRF steel tire to their line-up.

https://www.greenballtires.com/brand...tow-master-asc

[tech740]

Seems they are reacting to customers going up in load carrying safety margin. They are realizing they were not really in this game and giving options. Like anything else we will see what the next three years brings to determine reliability.

[CWtheMan]

Originally Posted by tech740

Seems they are reacting to customers going up in load carrying safety margin. They are realizing they were not really in this game and giving options. Like anything else we will see what the next three years brings to determine reliability.

Actually I'm going to view it as providing load capacity reserves. Wise consumers have always been screaming for those reserves. And, increased load capacity to meet the RVIA recommendation for load capacity reserves 10% above GAWR.

7000# vehicle certified axles are now being fitted with tires that will provide, at the very minimum, 3850# of load capacity. The ST235/80R16 LRG is the ideal fit.

8000# vehicle certified axles are now being fitted with tires that will provide, at the very minimum, 4400# of load capacity. The ST235/85R16 LRG sneaks' in that door with 4400# of load capacity @ 110 PSI.

With all these tires having increased load capacities there is no need to worry about changing designated size with replacements. For instance, the ST235/80R16 has 3 usable load ranges, LRE, LRF and LRG. The ST225/75R15 has 5 usable load ranges, LRC, LRD, LRE, LRF and LRG. Somewhere in those load ranges a consumer can satisfy his requirement for adequate load capacity reserves with replacement tires without having to change the designated size.

[tech740]

I have the ST235/85-16 LRF now. In the spring I will take them to LRG for more reserve. I have 7k axles.

[CWtheMan]

Originally Posted by tech740

I have the ST235/85-16 LRF now. In the spring I will take them to LRG for more reserve. I have 7k axles.

This is just a personal request for information on your trailer. Keystone very seldom provides axles with load capacity reserves. It invites trailer overloading. So my question is; Does your trailer's federal certification label list the GAWRs as 6600# or 7000#? At 7000# they would technically support a GVWR of 16500#, a 1000# over the certified GVWR.

I have noted that other Keystone trailers now have axle load capacity reserves and I'm wondering if that's a new Keystone axle standard? Our annual local RV show is next month and I'll be photographing certification labels on all Keystone trailers at that show.

Here's a Keystone certification label from the past that has matched the GAWRs to the installed OE tire maximum loads.



Note: The axle manufacturer's certification on those installed axles in the reference above was 5200#.

[tech740]

Mine is a Forest River but I am sure they use the same standards.

[CWtheMan]

Cargo capacity and trailer loading is a common subject in RV Trailer forums. The FMVSS standard 571.120 is one of the standards RV trailer manufacturers must comply with when building your trailer. Actually, the Trailer manufacturer does not have the final say about the maximum load your trailer can carry according to it's cargo capacity. That responsibility falls to the original selling dealer of the vehicle. If they install any options that total over 100# they MUST deduct the value from the label and provide a corrected copy at the time of first sale.

Sometimes really unhappy consumers are looking for answers about their trailer having too little cargo capacity. There is no relief as long as the manufacture’s listed cargo capacity does not cause overloading of the trailer’s GVWR. The following paragraph is from a NHTSA document that addresses what the vehicle manufacturer’s responsibilities are.

"The FMVSS have requirements for the manufacturer to use proper tires and rims for the gross axle weight rating (GAWR) and the gross vehicle weight rating (GVWR). The manufacturer may determine the GVWR by adding cargo capacity (if any) to the curb weight of the vehicle as manufactured. The wise consumer, before purchase, will determine if the vehicle has sufficient cargo capacity to carry the weight of water, additional equipment (such as televisions, and microwave ovens), and luggage. The manufacturer’s certification label must show the GVWR. The GVWR must not be exceeded by overloading the vehicle. There is little the government can do to assist a consumer who has purchased a vehicle that has insufficient cargo capacity for its intended use."

[CWtheMan]

With more and more steel cased radial tires being used on our RV trailers it becomes very important to become knowledgeable of the Zipper Rupture and how to visually inspect your steel cased tires.

Under inflation is a primary cause of Zipper Ruptures. If for some reason you find a steel cased radial tire at 80% of the normal recommended cold inflation pressure, it’s very possible that tire has entered into a zipper rupture condition and should be dismounted and inspected internally as well as externally.

When visually checking your steel cased radial tires during your walk-around, look for telltale small wires protruding from their sidewalls.

It doesn’t just happen to RV trailer tires. It happens to all steel cased radial tires.

Here's a picture. Very dangerous if you're standing there when it explodes.



The current steel cased radial RV trailer tires used as OEM on our trailers are listed below. My list may not include all of them.

LT235/85R16 LRG RST
ST235/80R16 LRG
ST235/85R16 LRG
ST225/75R15 LRF & LRG

As they become a more desirable RV trailer tire, I’m sure the off shore ST tire manufacturers will introduce more sizes with radial steel casings ( AKA, All Steel).

[gearhead]

Originally Posted by CWtheMan

This is just a personal request for information on your trailer. Keystone very seldom provides axles with load capacity reserves. It invites trailer overloading. So my question is; Does your trailer's federal certification label list the GAWRs as 6600# or 7000#? At 7000# they would technically support a GVWR of 16500#, a 1000# over the certified GVWR.

I have noted that other Keystone trailers now have axle load capacity reserves and I'm wondering if that's a new Keystone axle standard? Our annual local RV show is next month and I'll be photographing certification labels on all Keystone trailers at that show.

Here's a Keystone certification label from the past that has matched the GAWRs to the installed OE tire maximum loads.

Attachment 30526

Note: The axle manufacturer's certification on those installed axles in the reference above was 5200#.

Is a 5200# axle the same as a 6000# axle? Internally at least? I'm assuming the springs could be different.

[CWtheMan]

Originally Posted by gearhead

Is a 5200# axle the same as a 6000# axle? Internally at least? I'm assuming the springs could be different.

Actually its what the axle manufacturer certified it to be. It's certified to the weakest link. Items included with the axle that may have higher load ratings are providing load capacity reserves in that area.

Don't forget. The vehicle manufacturer has the authority to lower the axle manufacturers certification to an appropriate value to meet vehicle GAWR minimum requirements. The certification label on RV trailers is considered to be a final stage certification. It takes precedents' over all other items certification values.

[gearhead]

My interpretation of that is...they could re-rate a 6000# axle to 5200# which would still get them to reserve capacity and be able to put lower rated cheaper tires on it?

[flybouy]

Originally Posted by gearhead

My interpretation of that is...they could re-rate a 6000# axle to 5200# which would still get them to reserve capacity and be able to put lower rated cheaper tires on it?

I don't think putting "cheaper tires on it" is their end game. The axle manufacturer places their max load rating on what they build just as the tire manufacturer places the max load rating on what they build. Keystone assembles these components and computates what the maximum allowable weight on each axle is given the capacity of the frame, the tongue or pin and the balance of weight between the two axles and the tongue or pin.

If those combined factors say require a 5,200 lb axle but only a 5,000 lb or 6,000 lb axle is available then they have to go to the next size up and restrict that axle weight based on the bother components and factors. It's the "weakest link" in the chain that dictates the load capacity.

Then they go find the cheapest tire they find to slap on to that "well engineered" platform.

[gearhead]

Yeah I think we're on the same page.

[CWtheMan]

This is a listing of all steel constructed tires designed for trailer services. It’s not all conclusive but may come in handy when searching for new/replacement tires.

Sailun:
ST235/80R16 LRG
ST235/85R16 LRG

Carlisle:
ST225/75R15 LRF
ST235/80R16 LRG
ST235/85R16 LRG

Hercules:
ST225/75R15 LRF
ST225/90R16 LRG
ST235/80R16 LRG
ST235/85R16 LRG

Gladiator:
ST235/80R16 LRG
ST235/85R16 LRG

TransEagle:
ST225/75R15 LRF
ST225/75R15 LRG
ST225/90R16 LRG
ST235/80R16 LRG
ST235/85R16 LRG

BlackLion:
ST235/80R16 LRG
ST235/85R16 LRG

Provider:
ST235/85R16 LRG
ST215/75R17.5 LRH
ST235/75R17.5 LRJ

Triangle:
ST235/80R16 LRG
ST235/85R16 LRG

Two Master:
ST225/75R15 LRF
ST235/80R16 LRG
ST235/85R16 LRG

Heartland:
ST235/85R16 LRG

Trailer King:
ST235/80R16 LRG
ST235/85R16 LRG

Synergy:
ST235/85R16 LRG

Goodyear:
LT235/85R16 LRG (RST)

[gearhead]

Would the Sailun and Hercules steel 17.5 be considered trailer or medium duty truck tires? Not that it matters that much but they seem to be advertised both ways.
I'm thinking Hercules here lately. They seem to be more available "off the shelf".

[sourdough]

Originally Posted by gearhead

Would the Sailun and Hercules steel 17.5 be considered trailer or medium duty truck tires? Not that it matters that much but they seem to be advertised both ways.
I'm thinking Hercules here lately. They seem to be more available "off the shelf".

This doesn't address your question about the medium duty status but more about the Hercules brand. I don't know when they began making those but memory seems to recollect seeing the name Hercules on small town tire shops all over the place for years. I live in farming/oil country and just figured they were for flatbeds etc. and never considered them RV tires but if they're good and available.... I do know Sailuns must be getting much more popular. When I called to get some for this trailer before picking it up the tire dealer said he had 63 of them in his warehouse.

[CWtheMan]

Originally Posted by gearhead

Would the Sailun and Hercules steel 17.5 be considered trailer or medium duty truck tires? Not that it matters that much but they seem to be advertised both ways.
I'm thinking Hercules here lately. They seem to be more available "off the shelf".

They are low platform commercial trailer tires. Except Sailun, those are manufactured as ST tires.

Most of the RV trailers with 8000# axles come from the factory with 17.5" tires. The GY G114 seems to be the most popular.

[gearhead]

Originally Posted by sourdough

This doesn't address your question about the medium duty status but more about the Hercules brand. I don't know when they began making those but memory seems to recollect seeing the name Hercules on small town tire shops all over the place for years. I live in farming/oil country and just figured they were for flatbeds etc. and never considered them RV tires but if they're good and available.... I do know Sailuns must be getting much more popular. When I called to get some for this trailer before picking it up the tire dealer said he had 63 of them in his warehouse.

Same here Danny. I know a boy that hot shotted until a couple years ago. Typical rig...deleted Ram Cummins and a 40ft gooseneck. Hauling oilfield junk all over. He ran Hercules and was happy enough with them to recommend them to my son for his heavy duty low boy tongue pull. My son isn't very careful about checking air pressure or covering the tires from UV. I know those tires hauled a heavy construction tractor to Dallas and I pulled a Jeep Grand Cherokee across Houston on them.
There was, or is, a relationship between Cooper and Hercules. My small town tire shop owner said Cooper had input on the rubber formula. Who knows. I believe Hercules is owned by someone like American Tire Distributors, or similar.
Hercules may be easier to find, not sure. After our blowout I called several tire shops around Bernalillo NM. No one had a Sailun. I called Discount Tire and they recommended the Hercules or Provider. They had them in their local warehouse. I picked Hercules and had it installed the next morning. I have the Hercules dealer here in Liberty maybe 1/2 mile from me. I'm leaning in his direction. I'll pull the trigger after New Years.
Our 5th went to the shop September 21 for the blow out damage and they are just getting their estimate to State Farm. They did work a couple other small issues though. I've done business with this shop for 30+ years. May not be much longer. You know the saying: "shirtsleeves to shirtsleeves in 3 generations". Grandpa starts a business and works it hard to be a success, son inherits it and does well too, grandkids inherit it and put it on auto pilot and run it into the ditch.