Fred makes a good point. My 67 Caravel
has the original five lug OEM steel wheel that came with the trailer. The wheels showed some rust so I thought I might replace them. After reading a number of posts stating that the wheels on an airstream should be rated at 2600 lbs. I began my search for new 15" 5 on 4.5 OEM steel wheels. No luck. Best I could find were wheels rated at about 1850 lbs in steel and around 2000 lbs in aluminum.
This got me thinking (no, I didn't hurt myself) about the whole weight capacity issue. The original henschen axle on the trailer is rated at 3000 lbs. New 10" brake drums and assemblies to replace the existing 10" Brakes are are rated at around 1800 lbs each. The appropriate size metric tires to replace the original 7.75 x 15 tires (original size of tires used by Airstream on 67 Caravels) are ST207-75/15. These are rated at around 1800 lbs each.
Suddenly it all made sense, Axle, tires wheels brake drums all working together as a single suspension system. No one component with a significantly higher rating than another. My theory is that the folks that engineer this stuff for the various manfactures of components actually understand this relationship and don't over engineers the product. Why make a 2600 lb 5 on 4.5 steel wheel when the rating of the brake drum and assembly that supports the wheel is only 1800 lbs.
Some folks might want to upgrade all the components to have a larger weight margin. But I think the point Andy is always making about not over suspending the trailer good also makes sense. Anyway, decided sometime ago to stop fussing about whether the tires should have a larger weight rating than 1800 lbs or If I should continue my hunt for the 2600 5 on 4.5 steel wheel and go with suspension replacement parts consistent with what came with the trailer. This is the solution that works best for my peace of mind. Now if I could just get Andy to stop harping about the feeble axle spindles on the early Caravels I might be able to get a good nights sleep when I'm on the road.