Ken Ward wrote:
what's the story on tires? is it OK to use regular automotive radial
tires or are ST tires required?

thanks,
Ken

Almost no trailer loads a tire as much as a car.
That said- a couple things to consider-
A slightly lower profile tire can go a long way toward reducing
sidewall flex which does feed back to the towing vehicle as sway. Paul
Cordell found some cool inexpensive wheels for his Cobra trailer that
were larger in diameter allowing low profile tires and retaining ride
height.
MOST IMPORTANT- A not well know fact is that materials of tire
construction have changed and the usefull safe life is less due to
aging affects. Car manufacturers now specify replacement after 5 years.
This is mostly due to changes made to get long wear life and better
fuel economy.
The bottom line is it probably less important what you change to than
that you change.
Good luck UH