Solid rubber wheels on utility dolly

I don't use my dolly that often, but when I need it I get so aggravated because one thing is always true: the pneumatic tires are flat. These tires are not easy to inflate once the seal has been broken, and my air compressor bit the dust recently, so I decided to replace them with solid rubber tires from HF:

I also bought a box of cotter pins and drilled the axle to accept them. 15 minutes later -- presto! NO MORE FLAT TIRES.