There a couple of those rpod "hood river editions" in the storage area here at this resort, and I believe they may have the original factory tires on them. Both of them have either P or LT tires. I'll look at them when I go out for my bike ride today, and report back.
EDIT: I just looked at the factory website, and it says 235/75-15 off road tires. I think that is what I saw on these trailers here, were some sort of off road tread pattern like you'd see on a small truck.
EDIT 2: just went and looked at that R-pod, has "mudstar LT" on it.