Heavy Duty Swivel Casters

[needleworks]

I'm quite fond of my footmaster leveling castors:

http://www.footmaster.net/products/l...&small_code=GD

Some will be under 90mm, but they might not be appropriate for your case if you want quick setup and pack down.

Thanks for the link mate, I may end up going down this route, but to be honest this bench will never need to set down, it will always be mobile.