Anyone know the thread size for the crank bolt on a Koxx1 hub

I have a standard white russian, with a Koxx1 hub and cranks. I mangled the thread when removing the cranks last night, and need to get a tap to chase the threads. Also need some replacement crank bolts,

Thanks for any help.


Searching stuff like this tends to be pretty useful as this was just answered a couple of days ago.

As long as you have the reinforced hub, above are the thread specs for the crank bolts. The Koxx light hub will be M15x1.0.

Welcome to the forums.

So you’re saying they use larger crankbolts than kh/nimbus hubs??? Are you sure?

What? Are you sure you’re reading things right? Maybe I wrote that poorly.

Koxx (reinforced) ISIS, Nimbus ISIS, KH ISIS hubs all take M12x1.0 bolts. That is the standard size.

The Koxx “Light” hub takes bigger bolts M15x1.0. Since for the light hub there is a larger diameter hole drilled out (for more weight loss) it needs larger diameter bolts, hence the 15s.


ok, got it!
you wrote it fine, i just read it wrong on my blackberry

Hey, by the way- check the thread carefully on the tap. M12 x 1.25 is very common, but M12 x 1.0 is not. I don’t know why the 1.0 size was chosen; it would have made it a lot easier if the bike industry had gone with a more commonly available thread.


do you know any good sources for a m12x1.0 tap?


Good question; not sure what the answer is. I think they exist though; a machinist friend of mine has a M10x1.0 tap which I assume was part of a set at some point. If you find one definitely post about it. If you’ve only messed up the outer 1 or 2 threads, you may be able to fix it without needing a tap; might be worth taking it to a machine shop for that though.


This one should work.

Not if he has a standard White Russian, they have light hubs.

Oh snap!, here is the M15-1.0 tap. The link has all sorts of bike tools.

Thank you

I have the heavy duty hub, so the M12x1.0 is the tap required.

I managed to find one on Amazon,

$7.90 plus shipping.

Thanks for all your help !