I have been running the 31" radial bushwheels now since the first of the year in our "citified" environment here. I am running 8.5 pounds (you will note on the paperwork 8lbs is the minimum!) and could probably stand a pound or two more, but they are working great.
I would estimate we have done 250 concrete and asphalt landings on these tires (the supercub is our tailwheel trainer) as well as a lot of grass, corn, sand, and a few other surfaces. They are holding up great. I believe these tires have made this plane a lot safer, and frankly, a lot easier to land. Wheelies have never been easier and the touchdown is always soft!
For those who like "ramp appeal", these tires attract a LOT of attention and are becoming well know in the airport and in the KC Area. In fact, the folks at the FBO ask if I am going to fly "Tires" today. The PROBLEM is that I am the only one here with them, so when I fly somewhere where I am 501' AGL and someone believes I might be 499' instead and they call the feds, well, I am not hard to identify...
There is great article in this edition of Cub Clues on the Super Cub page by Mark Drath (a.k.a. SupercubMD) concerning big tires. Be sure to check it out.
Also, a little bird told me of some exciting things going on a Alaksan Bushweel.. Better keep an eye on their website for an announcement... Mum's the word...
sj