Thanks for the continued input JimNLin! I'll look at the other tires you mentioned today.
I emailed the folks who sell the wheels, Series06, this morning and Lowsuv was exactly correct in his prediction. The Series06 folks said the 65 psi would be fine on that wheel as long as we upgrade to a suitable valve stem with the load range D tire.
Knowing now that 65 psi is ok on the wheels, the 15" are sounding good again and that Goodyear Cargo G26 at 225/70R15 is sounding really good.
I'm going to contact the dealer that installed the EQ hitch and ask them what changes in height, 1" higher or lower, will do to the current EQ setup.
Many thanks again
