I use the R-10 with a locking small wheel and have used it every day for five years. I've only put air in the tires once and never had to do it again.

As for the shelf, the one that they make is a heavy, piece of junk. Several months ago I posted a photo of the shelf modification that I created, which consists of nothing more than two lengths of 1-inch box aluminum fitted with detent pins. It takes just 10 seconds to install, lightweight, easily stored and transported, completely corrosion proof. Cost about $40 and took 30 minutes to make using a hacksaw and drill. It is capable of supporting approximately 150 pounds.

From my perspective the Rock & Roller R-10 is the best thing since sliced bread.

Gary