I bought these wheels with the intention of using only swivel casters to replace the 2 fixed casters on my Rubbermade trolley. The bolt pattern worked fine, but I had to add about 1/4" steel washers to these wheels to match the height of the caster wheels that came with the cart. After doing this everything works beautifully now. Very handy having a cart with Having a zero turning radius works well in tight spaces.