caster wheel material?

[jawsfree]

What is the best material for caster wheels in the brewhouse? I have my yeast bank keg that is on casters and they have disintegrated in just 2 years.
They did roll really well until they started falling apart.

[gitchegumee]

My recommendation is NOT to use caster wheels. Those tiny wheels hiccup and fail on everything that isn't a smooth, perfect surface. Instead, use large plastic hub pneumatic wheels like a hand truck. They will allow you to easily hop over power lines, hoses, and small curbs. Smoother & easier travel, too. IMO, caster wheels are useless on most anything in a brewery.