Upgrade Hispec to Endurance= 110psi to 80psi ???

[Jethrone]

I have a Yukon 2022 399ML and want to upgrade our tires. Currently have 235/80R16 @ 110PSI.

When I look at Endurance for same size it shows a lower load range and (obviously) lower psi with corresponding lower load.

Even if I moved up to a 235/85R16 it is still showing max 80psi.

Am I missing something???
I plan on going into the store to discuss but thought there might be some expertise here.

 

[dsol]

They have an older chart that shows the 235/85 had various load ranges that exceed 80 PSI.

At 80 PSI it shows 3,640, at 95PSI it shows 3,960 and at 110PSI it shows 4,400. However I am seeing this chart in a few trailer forums but not on current Goodyear website. If you Google the Goodyear Endurance load range chart you will find it.

In my research these tires had the highest load rating at 80 PSI. There were higher ratings at higher PSI but I prefer 80 with my rims as they are stock and the stock China bombs (Westlake's) that came on the trailer were rated for 80 PSI and I really didn't want to run higher than that. My feeling is that any component that comes on these trailers from the factory is the cheapest quality stuff out there so I don't want to push my luck.

I have a two axle TH (Dutchmen 3305) and while there are bigger and heavier trailers out there, I don't think any have two axles like mine. IMO this trailer probably should have come from the factory with 3 axles and thus less load capacity per tire (and leaf springs, shackle, etc.--but hat is another story.) but I trusted the manufacturer and didn't know then what I know now.

Anyway, back on the subject, I would be surprised if these Endurance tires at 80PSI didn't have sufficient capacity compared to the OEM tires, although if current tires call for 110PSI then I could be wrong.

 

[Franktafl]

Look at cooper Roadmaster tires. Mine pump up to 125# and have an absolutely wonderful warranty and are regrooveable.

 

[Tireman9]

#1 The tires must be rated to deliver the load sufficient to support 110% of GAWR per RVIA guidelines.


If the tires you are looking at do not meet that requirement then you have to find tires that will deliver that load capacity.




What SIZE and Load Range is listed on your Certification Label?

 

[Ckparker2013]

Why on earth would you want to go with a lower load range tire? Check and see if Goodyear has an equal or higher load range, to meet your requirements, in the Endurance line.

 

[leisuresolar@gmail.com]

trust a pro

Tireman is a pre tire guy. Trust what he says. There are a couple of pro's on here, find them and trust them.

 

[Jethrone]

Ok, well I finally figured out the problem I was having in the process. For some reason I was not thinking of the ply. 10/14/16 ply. Not sure why it wasn’t registering but sorted now. So now I will have to look at Carlisle/now Carlstar in order to meet the load rating.

 

[Tireman9]

Ok, well I finally figured out the problem I was having in the process. For some reason I was not thinking of the ply. 10/14/16 ply. Not sure why it wasn’t registering but sorted now. So now I will have to look at Carlisle/now Carlstar in order to meet the load rating.

Ya "Ply" started to go away in the late 1960's when stronger Nylon went into Bias Ply tires and we were making "6 for 8 Ply" tires. With the "Truth in labeling" movement and the switch to Radial construction in the 70's "Ply Rating" went away officially to be replaced with "Load Range". Which uses a Letter rating C, D, E etc



However many people in the RV community insist on using the term "Ply" without including the word "Rating" so sometimes they can confuse themselves.



Almost all Radial tires have a single (one) body ply. Tire engineers use increased strength cord for the body "ply" as there are some industry standard tests to measure the "strength" of a tire. The DOT testing has a series of tests with ever increasing levels of "force" required to break or rupture the body of a tire.


If you bother to read the material list molded on the sidewall of all tires you will see that most ST type tires and LT type tires have just one layer or ply of Polyester in the sidewall. For Load range C, D, and E tires you will also see two layer of Steel. There are some tires that also have 1 or 2 layers of Nylon on top of the steel belts. There are some tires that use materials other than Polyester for the body cord.
In general moving to larger size tires in 19.5", 22.5" sizes and Load Ranges such as F, G, H etc you will see the sidewalls will be 1 Ply or layer of steel and the belts will be 3, 4 or even 5 layers of steel.


No matter the number of layers or the materials used all Load Range E tires must pass the same "strength" level.


You also need to know that the "Strength" test is not directly related to a tires load capacity, as Load capacity is based on the air volume and the inflation level and only the inflation level is relative to the strength level measured in the DOT testing.


See none of this is simple and that is why there are "Tire design Engineers" who spend their careers learning, developing and designing tires to meed the needs of our customers and the goals of the tire companies.

 

[Winnie-DUTCH]

I am reading this thread trying to determine what tire to run on my 2017 Voltage 3305 2 axle toy hauler. I’ve ran the GY G614 235x80x16 for six years and have had no complaints.
Problem, the new G614’s are rated 3750# @110PSI, my trailer weighs 16.5K, so I assume I need 4125# per tire. Am I missing something?
What confuses me is that the axles are rated at 7000#, according to Dutchman the axles are calculated to carry 80% of GVWR. If that’s the case, then why do the tires need to carry 100% GVWR?

 

[Tireman9]

Tires carry capacity is related directly to GAWR not GVWR. Currently RVIA recommends that tires be able to support 110% of GAWR.

 

[Winnie-DUTCH]

Tires carry capacity is related directly to GAWR not GVWR. Currently RVIA recommends that tires be able to support 110% of GAWR.

Thanks for the reply and clarification. All my research is returning GVWR not GAWR, GAWR makes more sense to me, plus it is more realistic to find a tire with that capability. Do you think the RVIA 110% recommendation conveys lack of confidence in the tire manufacturers weight ratings, or simply recommending a safety factor?

 

[Winnie-DUTCH]

Thanks for the reply and clarification. All my research is returning GVWR not GAWR, GAWR makes more sense to me, plus it is more realistic to find a tire with that capability. Do you think the RVIA 110% recommendation conveys lack of confidence in the tire manufacturers weight ratings, or simply recommending a safety factor?

Also, I find it interesting that the Endurance has a better rating of 3960 @95PSI than the more expensive G614 3415 @95PSI.

 

[Tireman9]

Tires in trailer application suffer from "Interply Shear" which places forces on the belts of the tire that are trying to tear the belts off the carcass. These forces are about 25% higher than the forces experienced by tires on motor vehicles so 10% is a partial offset. I have a number of posts on this topic "Interply Shear" on my blog but this one will give you a basic understanding WARNING - Super Technical Post Tire failure and Interply Shear

 

[dsol]

I am reading this thread trying to determine what tire to run on my 2017 Voltage 3305 2 axle toy hauler. I’ve ran the GY G614 235x80x16 for six years and have had no complaints.
Problem, the new G614’s are rated 3750# @110PSI, my trailer weighs 16.5K, so I assume I need 4125# per tire. Am I missing something?
What confuses me is that the axles are rated at 7000#, according to Dutchman the axles are calculated to carry 80% of GVWR. If that’s the case, then why do the tires need to carry 100% GVWR?

You need to take into account that somewhere around 10-15% of your tires weight is carried by the tow vehicle, or truck. I have the same exact trailer as you and I have notes that indicate a pin weight of 2,913 lbs. That means your 16.5k lb. trailer has to support 16.5k less 2.9k on the pin or truck. This equates to 13.6k on the axles or 6.8k per axle, or 3.4k per tire. The Goodyear Endurance at 80PSI is good for 3,640 lbs. per tire which gives you 240 lbs. of excess capacity per tire. While that is not 10% as recommended by Tireman9 it is about 7%.

A couple of other things to consider. The Goodyear Endurance is the only trailer tire I am aware of that is actually manufactured in the US. While I do not know this to be certain, I would put better stock in the quality control here than is some plant in China.

Secondly, the Endurance has an N speed rating of 87 mph. I am not aware of any other trailer tire that comes near that. And to be able to achieve that speed rating at only 80PSI instead of 110 tells me my trailer isn't bouncing around as hard for hours on end while towing.

I actually have a hard time finding a speed rating on most trailer tires. While I am sure that most RVer's would say towing a 16,000 lb trailer at 87 mph is crazy and would never do it, including me, it is still nice knowing that DOT has rated that tire to sustain 87 mph for several hours. On open highway with miles of long straights it is very easy to find yourself towing at 70 mph and knowing your tire is rated to do it provides some comfort.

Good luck!

 

[Tireman9]

In the US "Speed Rating" is really a measure of tolerance for high heat and is based on a 10-minute long test with speed increasing every 10 minutes till the tire fails. In Europe, Asia and the rest of the world, they do not offer an ST type tire because their speed tests are more realistic and stringent.
When ST type tires were introduced to the US market some 40 years ago, they were given a higher load capacity rating than a same-size LT tire BUT the trade-off was STATED in the industry standards books as having a max operating speed of 65 mph. With 50 years of Tire design and testing under my belt, I know of no "Magic" rubber that will deliver greater load capacity for a given size and inflation without some trade-off.
There are only 5 variables. Size, Load, Inflation, speed and the ability to be rated for operation with passengers in the vehicle, so unless you invent some "magic rubber" you are limited by physics. Yes, materials have improved over the last 40 years after the switch to Radial construction and we have seen improvements in tire performance, but have you ever asked why a company can make a tire of the same physical size and same load capacity at a given inflation and somehow make one tire carry significantly more load than the other without some trade-off in operation speed?
If I had invented some "Super Magic Rubber" for ST type tires that gave them "Super Strength" why wouldn't I put the Super Rubber in the other other I make and sell and take over the worldwide tire market? Any company can ignore reality and make a marketing decision and claim a "Speed Rating".