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Old 10-14-2020, 02:54 PM   #81
Tireman9
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Join Date: Sep 2018
Location: Akron
Posts: 453
Quote:
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.
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Retired Tire Design Engineer (40 years). Serve on FMCA Tech Advisory Committee. Write a blog RV Tire Safety. Read THIS post on Why Tires Fail.
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