These wheels are great for a serious, heavy wagon (obviously you'll have to buy four, not two. They can take a serious load (200 pounds per wheel) and make it easy to move that load to where you need it. And most importantly, the brakes work great.
Pros
Dimensions: 1-1/2" wide x 8" wheel diameter, 4-3/8" x 5-3/8" mounting plate, 9-1/4" clearance height