What size is the rear axle nut?

[Shumaki]

I need to remove my rear tire to replace the valve stem. My allen wrenches don't go big enough so I need to borrow or buy one to fit. It would be helpful to know what size I need. Holding up an open end wrench for comparison, it looks like about 12mm. Can anyone tell me for sure?

[ninja11zx]

8mm on one side and 12mm on the other. if you cant find them you can use mine. just give me a call.

[jay jay]

its a 12mm i just ran into that problem the other day