I Just happen to have disassembled one wheel from my cattrack, going to take it to a local tyre centre to see if the can plug a leak foor me. Does anyone know if that is feasible or not? Anyway I have taken some pictures of my trusty old cattrack to illustrate some of the points people have made in this thread. I don't know my cattrax's age, I bought it secondhand together with my boat. It appears to be old, but apart from the leaking tyre it does its job well.