GY Tire Bulletin

[mamestra]

I'm not sure that I would want to but 90 psi in the MarathonsI had 80 psi in the summer when the temperature was in the 90's my tire pressure monitor was recording pressures of over 95 psi I don't know how comfortable I would be at pressures of over 100 psi in these tires. We had a blowout when temperatures were in the 60's and I was travelling at 55 mph pressure monitor wasn't upset so pressure was correct.
I no longer have Marathons.

[Art-n-Marge]

When the Goodyear engineers look at a rating they are supposed to account for the increase in pressure as they warm up and consider this when recommending a pressure. Since they are the ones that recommend 90 psi cold, then they have probably considered the high temps of driving and climate.

I wouldn't worry about their psi increase. A tire can failure for other reasons than this and since so many of us have run these at 80 psi and they've blown, I don't think it was because of the pressure.

[bobcat92]

When we swapped out the marathons the tire guy said they are great tires but Keystone should be sued for putting an under rated tire on a heavy trailer as we have. He puts them on lighter trailers and they work great.

It would interesting to talk to one of the Goodyear engineers.

[bncinwv]

It is not correct in assuming that Keystone is the only manufacturer using these tires on the larger rigs. Keystone could not be singled out in a lawsuit when other manufacturers are doing the same thing. The tires meet the weight ratings that are the determining factor. They may not have a safety margin that is acceptable to many, but they meet the rating requirements. Now with all that said, I do not have Marathons since I explained to the dealer upfront that the sale was dependent on the tires being replaced before the rig left the lot.
The engineers would tell you check the weight ratings and do the math.
Bingo

[8.1al]

Not saying I like it but most rv manufacturers are on the edge with the tires they put on their trailers