The soft rubber wheels are made by Darnell-Rose, and product number/markings on them show “Darnell Corp X-6 2 1-2 Calf.”. Unfortunately, I can’t find my original receipt nor the wheel in Darnell’s catalog or California Caster’s website. If I find it I’ll try and remember to update this post, but I think if you call up and say X-6 2- 1-2, you be okay.
oh! and a point of clarification, I’m still using the original Proctor Glove / Arrow Hardware caster assembly
Left: Original Proctor Glove wheel – shaved down to 2.5″
Middle: New Darnell wheel
Right: Full Proctor Glove 3″ caster