I will be visiting a friend in the States soon and, as her shower chair is in need of new wheel bearings, would like to replace them while I'm there.

Obviously I'd rather know the size of bearings I'll need (and have sourced them) before I start any work on the chair, but ActiveAid have been less than forthcoming with any useful information.
Therefore, it was with great joy that I stumbled upon the wealth of knowledge, experience, and wisdom contained within this forum (enough flattery?).

So.. does anyone happen to know the size of real wheel (20") bearing required for an ActiveAid JTG 620SS shower/commode chair?

Any and all assistance/observations/opinions greatly appreciated.