Originally Posted by
Steely Dan
... anything should work as long as your diameters match up
The diameters don't have to match either. I've used 700c tubes in 26" wheels several times when helping out stranded riders on MTBs and once even used a 700c tube in someone's 12" trailer tire. Also needed to use a 406 (20") tube in a 451 (also nominally 20") tire once - that one was a little harder to install but it worked fine.