17mm hex

[mistercrash]

And this is what was said about the nut. It works this has been race tested and I never lost a wheel. I don't even use Locktite anymore.


And one last thing I did about the set screw. I install the adapter and thingamajiger on a stub axle, chuck it in the drill press and with a cut off wheel on my Dremel, I make a slot all around for an O ring. No need for Locktite and no more lost set screws. The O ring keeps it from backing out too far.