Second Blow Out, Gremlins? Chinese Tires?

[switz]

An official answer for Bob in post 59 from the US Government:

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49 CFR 571.110

Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of 4,536 kilograms (10,000 pounds) or less.


S4.2.2.1
Except as provided in S4.2.2.2, the sum of the maximum load ratings of the tires fitted to an axle shall not be less than the GAWR of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. If the certification label shows more than one GAWR for the axle system, the sum shall be not less than the GAWR corresponding to the size designation of the tires fitted to the axle.

S4.2.2.2
When passenger car tires are installed on an MPV, truck, bus, or trailer, each tire's load rating is reduced by dividing it by 1.10 before determining, under S4.2.2.1, the sum of the maximum load ratings of the tires fitted to an axle.

S4.2.2.3
(a) For vehicles, except trailers with no designated seating positions, equipped with passenger car tires, the vehicle normal load on the tire shall be no greater than 94 percent of the derated load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.
(b) For vehicles, except trailers with no designated seating positions, equipped with LT tires, the vehicle normal load on the tire shall be no greater than 94 percent of the load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.

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This is the official word we all have to abide by to maintain our insurance coverage to avoid being considered reckless and thus no insurance coverage......

I upgraded to the SenDel 16" T03-66655T aluminum wheels which have a wheel rating of 3,580 pounds at 80 psi which is 900 pounds more rating than the Michelin LT225/75R16/E LTX M/S2 tires I installed (2,680 pounds at 80, psi). Their galvanized steel S62-66655TG wheel which I used for a spare is only rated 3,500 pounds. These tires and wheels are now standard on the 2015 Classic and have been optional on the Eddie Bauer models.

When I upgraded our 2013 25 FB International Serenity with a GVW of 7,300 pounds to the Michelin LTX (P) 235/75R15 XL tires with a sidewall rating of 2,183 pounds at 50 psi, we applied the required 10% weight reduction to 1,985 pounds capacity for a total tire load capacity of 7,940 pounds. Since we had a 1,175 pound tongue weight, the four tires were only supporting 6,125 pounds or 1,541 pound each. That was a better than 23% load safety margin.

That margin for the 25FB with passenger tires is far greater then the margin on our 2014 Classic with a GVW of 10,000 pounds with the factory installed GoodYear Marathons rated 2,540 pounds tab 65 psi. Using the literature tongue weight of 733 pounds, the tires are supporting 9,267 pounds or 2,214 pounds on each tire which is a margin of 13%.

[Tireman9]

I'm on vacation in Oregon and don't always have good WiFi. BUT
CapriRacer did a great job covering the points regarding the rules & regulations.
The 10% reduction ( technically 1/1.1 or .90909 but 10% is easier to remember and calculate) is decades old info for those who know where to look.
When anyone makes a decision to change tires of any type or size from original there is a LOT of research that SHOULD be done first. Tires are not just round black things but are much more complex than most realize.

Hope we have answered your questions Bob.

[jnerges]

Oh yea, I forgot to tell you. Goodyear replaced the Marathon at no charge. No further problems. I do keep the tires inflated though. A good lesson for me.