You don't give the full size info, but the only 235/16 trailer tires that tirerack.com lists are 235/80-16 so I'll assume those. For Goodyears the D rated, 8 ply is rated at 3000 lbs at 65 psi and the E rated 10 ply is rated at 3400 lbs at 80 psi. Your axles are rated at 3500 lbs each so at a bare minimum you need tires rated at 3500/2=1750 lbs each so both tires are overkill for you. In other tire sizes you can get C rated tires that would be cheaper yet. In their tech info they say that if you use a car tire you have to derate the load rating by 9% when you use it on a trailer, so maybe you could also look at car tires in the 2000+ lb rating. Staying with trailer tires and going to a rating higher than you need gets you a stiffer sidewall which can be good if you have sway issues. Me, I'd go with trailer tires D rated on 3500 lb axles and E rated on 5000 lb axles. I would probably never need that capacity but I believe in insurance :-).
----- Regards, Carl Ijames
I need five 235/16 tires for my trailer. It has tandem axles. It will be carrying about 5,000# max on two 3500# axles. I will get trailer rated tires. What ply should I go with? Do I need 10 ply sidewalls? If they aren't a lot more, I'm a fan of overkill, but was just wondering about how much tire to put on there. Not a lot of freeway driving, 50 miles max at a time, and I'd be running 60-65 depending on how this acts once I get it all together. It does have the big hitch with the stabilizer bars.