Its the odd sizes that bug me......13mm? You look at the bolt, figure its a 12, get down on the ground and try it but no, 12 is too small. So you get back up and get the 14, and get back on the ground and try it.....but no its too big....WTF? Several months go by and you forget about it, and do the same thing all over again.
Is there really any reason to use 13mm except to get some sadistic pleasure out of frustrating home mechanics? No other metric bike I have owned has had the odd sizes the triumph has.