Clas C and tires

SJ-Chris wrote:
....... Does anyone else feel like this is an uncomfortably LOW margin? .....

This is a little less than what I think is prundent, but not too bad.

SJ-Chris wrote:
....... Does anyone know, generally speaking, how the manufacturer comes up with those max axle weights? ......

Yes, they pay attention to how strong each component is and publish the weakest one. On motorized vehicles, it used to be the tires was the weakest link, but nowadays, it is usually something else.

SJ-Chris wrote:
....... Is the manufacturer adding that all in when coming up with their max load ratings? .....

He's supposed to, but usually these are chassis's made by someone else, on which a box is made and sometimes the converter doesn't do a good job.

SJ-Chris wrote:
....... Q: Is the max PSI always stamped on rims??? ......

No, unlike tires, wheels are not required to stamp weight and load limits. From what wheel engineers have told me, the bolt pattern of the wheel describes what vehicles those wheels go on, and the wheels are designed accordingly. They have also told me - in a round about way - that load is the key parameter, and inflation pressure isn't - that the wheels can withstand a lot more pressure than the max pressure of the tires that can be put on.

SJ-Chris wrote:
....... Assuming that my rims were rated with enough PSI, can anyone think of a drawback of going with an F rated tire that can more easily handle the heavy load of an RV? Wouldn't it cause the tires to "work" less and therefore be less likely to have a WEIGHT CAUSED blowout? .....

You have to use the increased inflation pressure to get that increased load carrying capacity - and that means a harsher ride.

And just a side thought: If the tire at Pep Boys is the Sunfull brand - the only Load Range F tire I saw, - never heard of them. They might be made in China, so I would proceed with caution.