Originally Posted by
HTupolev
(I guess you could *in theory* build a single-wall rim with a rounded bottom and an ultra-deep center channel.
You need not speculate. Rims like this absolutely do exist. The people posting in this thread about thousand-dollar wheelsets probably haven't seen them but they showed up on cheap fixies 10-15 years ago when that was all the rage. I got one with a bike a while back and it was a real tube-eater, the rim strip would not stay put over the nipples.
Ultra-deep is relative, it's not 50mm. The tube has to go somewhere