front axle help 11 ec300
 

Hey guys, no longer a gas gas virgin and I'm loving it. Just purchased a 2011 ec300 last week.
I was hoping someone can tell me what size the front axle thread is. WHen removing the from wheel it looks like the stock hex head nut threads are slightly stripped. So I purchased a new 22mm nut as a replacement but it will not go. I thought the axle thread was 22mm with a pitch of 1.5mm.
Could it be the axle is ever so slightly out of round?

cheers guys