All doorway and western dollies use treadless tires for that very reason. You can probably buy them someplace to replace the knobby ones.

I've noticed that most garden variety wheelbarrows seem to have inflatable but smooth-surface tires...

you can get the smooth tires at Les Schwab tire center

Knobby tires or smooth?
 

I've used a cart exactly like that from Harbor Freight for a number of years. It works really well and I've never had a problem with the knobby tires...probably because I slightly under-inflate them to compensate for any bumps or imperfections in the surface I'm dollying on.

I read some bad reviews of Harbor Freight so I did a search for another vendor... Apparently Amazon sells this thing too, through a reseller named Northern Tools.

http://www.amazon.com/exec/obidos/tg...&s=home-garden

Hmmm, Northern Tool has an even worse reseller rating then Harbor Freight (links to resellerratings reviews).

Cheers,
Brian

I've used a garden cart like many pictured here, including the knobby tires. The tires aren't the worst part. It's the handle and the way the front tires are articulated that'll get you. Typical wagon style center pivot will cause the whole thing to tumble over if you turn too sharply. My cart has a steering frame that turns both wheels hinged at the axle end, much like a car. But it shares the same problem as the wagons -- they can only be successfully pulled, not pushed.

The cart in the starwars photo was being pushed by a wide handle and it does not look like it can be steered, providing a more stable ride and allowing the operator to see the camerman and receive cues from him.