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Old 10-14-2020, 02:54 PM   #81
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Join Date: Sep 2018
Location: Akron
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Originally Posted by CWtheMan View Post
I'll put it a different way. According to the specs for the OPs trailer the GAWRs cannot be LESS than 7000#.

Sorry, I thought you might provide more light. I already knew everything you have posted.

FMVSS allows more than one measured load for tires. An example is the ST235/80R16 LRE with three different load capacities at 80 PSI. FMVSS tells the vehicle manufacturer they can use the higher load when documented. Without documentation the load defaults to the lowest load.

In this case the load is equal to one step up on the inflation chart, providing a completely different picture for selection of future replacements.

I don't like the way DOT allows some to play with the requirements. If they are going to allow one manufacturer to "invent" a load capacity that is different that waht is published in TRA then the least they should do is then tell the RV owner there is only one brand tire that is an acceptable replacement for that specific RV. I don't think the RV company would like that becasue the RV owner would normally want to be able to shop for tires and not be required to use just one brand. It could even be argued that the RV company would need to stock replacement tires in that specific configuration for say 10 years for to switch brands to another tire company that didn't make their tires with the special specifications.

I ran into this once when I discovered a tire with sidewall numbers that were not standars but eventually learned from NHTSA that there was a "letter" in the system that that specific tire was approved with the special load capacity even though the tire didn't say anything.

In the case above, we would need a lot more details. If I have images of certification tables and tire load capacities as marked on tires I would be willing to go to NHTSA and ask how they were planning to ensure all future tires met the same special circumstances. I probably would have a great deal of trouble geting a rational and consistent answer but I would enjoy making NHTSA squirm because they were playing games with tire fitment requirements.

Retired Tire Design Engineer (40 years) On FMCA Tech Advisory Committee. Write a blog RV Tire Safety. Read THIS post on Why Tires Fail.
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Old 10-14-2020, 06:22 PM   #82
Join Date: Aug 2018
Location: Arlington
Posts: 79
Originally Posted by CWtheMan View Post
The tire in your picture produces 4080# of load capacity at 110 PSI.

Yeah...I never corrected the post but was aware of the typo. I saw the (up to) 4400lb in the marketing before reading the table. Nonetheless, still an upgrade in tire and capacity for me, and covers my scaled axel weights.

2015 F-350 CC LB SRW Platinum
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Old 10-14-2020, 06:32 PM   #83
Join Date: Aug 2018
Location: Arlington
Posts: 79
Originally Posted by Tireman9 View Post
Well we are missing some information RVIA 110% is based on the stated GAWR and no one has provided a nice picture of the tire certification label so we get all the information in one place.

It's Keystone that sets the inflation number and GAWR, They can select any tire that has the numbers published.

New sizes and Load Range combinations get added to TRA tables when a tire company requests. So it could be a one off, but having more facts would help.
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2015 F-350 CC LB SRW Platinum
B&W Ford Puck Mount Companion Hitch
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Old 10-15-2020, 03:51 AM   #84
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Join Date: Apr 2020
Location: League City
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Originally Posted by Tireman9 View Post
Sidewall split and the sharp bent rim is evidence of hitting something. When did you last do a "Free Spin" inspection as I cover in my RV Tire Safety blog?
This was only the 2nd trip on the camper, and the tires were just checked at the tire store for balance, inflation, etc. The tire rim was bent after having to drive on it for a bit to get off of the freeway, not from hitting anything. The manufacturer has since told me that it was a separataion of the tread that causes this issue, and is not uncommon for this type of tire. On popups, the tires are very small, and the rims are thiner. Because it was comming back from the tire shop, there was no load in it. While I appreciate that you know alot more than I do about tires, they have been inspected more times than most folks would normally do. Again, even the manufacturer called them China Bombs, so that is where I get the term. I really think that it had alot to do with just the age of the tire, but, who really knows. Now, we check them every time we stop, and, I do lift them up and check for separation before every trip.
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Old 10-15-2020, 07:21 AM   #85
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"Originally Posted by Tireman9 View Post
Sidewall split and the sharp bent rim is evidence of hitting something. When did you last do a "Free Spin" inspection as I cover in my RV Tire Safety blog?"

Couple of things about this statement that are disturbing to me and it's not the "self promotion of your blog".

First is ASSUMING the failure is the operators fault. A post mortem of a tire failure based on rim damage is concerning. I'm not a "self proclaimed expert" but how can one differentiate how and when rim damage occurs?

A tire blow out is typically a very violent occurrence that can result not only the rim striking the road surface suddenly but also can end up with dramatic sway that can end up with the tire running on the shoulder or dropping off and back onto the road surface which may be at several inches of elevation difference with aggressive edges. This all typically happens at highway speed. The blowout often does serious damage to the trailer itself tearing loose iron gas pipes, sections of flooring, sidewall, etc.

So without witnessing the event or even seeing the road surface you determined that it was the owners "fault". This seems all to familiar whenever there's a tire failure it's never that the tire isn't the issue. I think we all understand the importance of proper air inflation and maintenance but to jump to the conclusion that it's the drivers fault is wrong.

I often see the defense of the tire industry laid at the feet of recalls. I don't think most trailer tire failures go much past the landfill or reported past the owner's insurance company.

The second issue is the the "free spin inspection". That in my opinion is a diagnostic procedure not a maintenance issue. I have done this when I've had a steering issue such as pulling to one side, or hearing a thumping noise. Then I'll look at the tread looking for defects that would indicate a belt shift for example. Typically if this happens I'll head to the tire shop and have them do it as not only is it easier on a lift but if that's the issue then obviously I'm going to need their devices.

When was the last time you jacked up each corner of your truck or car to perform a "free spin test"? The fact that you asked this question points to the tires being "inherently problematic". When you compare the fairly frequent failure of a few brands of trailer tires than I think the issue goes beyond "operator error". If you extrapolate the percentages out to passenger vehicles Firestone and FMC ended a nearly century old relationship and millions were spent in and out of the courtroom.

As with most issues this goes deeper than what surfaces in the media (news or social) and I believe we should strive not to "point blame" without a reasonable amount of knowledge.


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