Yeah, a normal tube out of the tire blows up pretty big but with the posted one for that cheap I would buy the right size. Just hadn't seen that one. So, anyone with this thing mounted, care to give us a width measurement? I imagine my WCC frame would hold it but the crank would need to be modified to bring the chain out. Something being discussed in another thread right now. I would just have to be certain it would fit before I order one. There's still 4 left! Who can measure the size please?