I'm running tube-LESS spoke wheels from Woody's. They work fine and hold air. I'm sure he can do the same thing with 18" & 21" as he did with 19 & 17. Guess I don't see the fuss.
“If liberty means anything at all, it means the right to tell people what they do not want to hear.”
'06 525 XC "Sledge"
'04 KTM 950 Adventure Thunder
Enough yappin'! Let's ride!