I'm not well versed in derailleur setups since all my bikes have hub gears. I'm doing some maintenance on a friends Mu P8 (2007) and I think the freehub body is shot since there's a lot of play there and the bearings feel rough. I've just discovered I need a 12mm allen key (it looks like 12 to me but could be 11) to take the freehub off. . . I don't have one just yet. Anyone know what might serve as a replacement or will I have to order a whole new Kinetix hub?