Well fxxk me dead,the old Sherman got a puncture in the knobby.Careful visual examination shows nothing. I dumped 5 oz of Slime in the tube and it was flat the next day.I dumped the rest of the Slime ( 3 oz) in and the bastard is still flat.I,m thinking now there must be a hole in the valve stem somewhere that probably got ther e as u bend the valve stem a bit to inflate the tyre. Anyone know what size tube i need and (where to order it) and whether its easier to split the wheel in two leaving all the motorwires connected or disconnect everything from the top and drag the wheel out from the bottom?