Do you even *need* a suspension?

[KCStudly]

Seems to me they have softer shoulders (more rounded edges between the side wall and tread) which helps reduce scuffing while turning in multiple axle applications.

[Martiangod]

Trailer tires are made in china, where all the best stuff is made.
30 years in the RV bizz as a tech, i'll stick to my low profile car tires on my personal rig, thank you very much.
Chinese can't even make a valve stem that will last more then a couple months, how the heck are they gonna make a tire any better?
there was a time when a trailer tire would last forever, 30 years parked and still holding air, now a weekly ritual is going around the yard and pulling new tires that have gone flat and taking them to a tire shop to fix them.
Funny that as the weight increases on RVS, they go away from trailer tires and move to LT's
I see many many trailer tires with a blow out in the sidewall as big as a basketball, now when these tires blow they usually do extensive damage to the side of the rv or cause the rv to roll over.

[Knolly]

These, on the other hand, do not have any suspension and are similar to the one eggsallad posted

Trailer In A Bag
http://trailerinabag.com/index.html

The manufacturer claims safe at highway speeds and the users are hauling high-dollar motorcycles.

Just figured I'd chime in, I had one of these trailers and it was excellent, had no problems at all taking it above highway speeds. However, the reason it worked is that it wouldn't damage the cargo because the motorcycle's suspension could sort of compensate for bumps and whatnot in the road. I towed it empty a couple of times and I could see the tires skipping around a bit in my mirrors. When it was loaded, however, it was incredibly stable. I only sold mine because I wanted a larger flatbed trailer for hauling some things with my motorcycle that didn't fit in my Ford Fiesta.