So I was doing some maintenance on my old MTB wheels last night and for the first time I noticed that the rim size is stamped on the rim. It says "E.T.R.T.O. 599x22 26x1.75" on both rims although I've always used standard 559mm BSD mountain bike tires on them. And I thought E.T.R.T.O designations were supposed to lead to less confusion in tire sizing.