http://taskmasterproducts.com/products/provider-st-radial/ Provider ST tires have been around the commercial trailer industry for 4-5 years now with the 16" E/G load rating and the 17.5" H load range being the most used. They have the nylon cap that seems popular.
My area equipment trailer mfg uses the smaller 14"/15" on cargo/etc trailers.
These are "M" (81 mph) speed rated.
Carlisle's new ST RH looks 100 percent better than the old basketball shape sidewalls with the rounded tread tires of the past that resemble wheel barrow tires. I think some ST tire makers are on the right track.....time (7-10) and miles (30k-40k) will tell the tale.
IMO Goodyear will at some point step up with a redesign on the Marathon as Carlisle has done.