Retapping (Koxx)ISIS Hub Threads?

I’ve got an older koxx-one hub which seems to have an issue with its threads. I don’t have the original bolts but I tested the hub with my KH ISIS bolts and they only thread in about two rotations where it gets really hard to turn and stops. I’m not sure if this is maybe just the wrong bolt or if the threads need to be retapped. If someone has any idea what I should do I’d greatly appreciate it.

thread jack, but what is retappiing??

Check the threads, are they stripped or messed up somehow? Any little bits of metal sticking out?

I had to have the threads on the crank retapped once. It cost like under $5 at a bikeshop.

Yeah the threads look a little mucked up but it doesn’t look too terrible. I took it to a bike shop but they said they didn’t have the right tap for it.

There is also a lot of anti-seize in there so if some of it looks grey, that’s why.

Ah okay, so with all of this being said. Do the Koxx and KH hubs take the same size ISIS bolt? Also, if I take it into a bike shop to be retapped, what size thread needs to be tapped?

If it is the same size as the KH you wont find the tap at the LBS, I had to go to a Machining Shop that specialized in metric as it is a large tap with a very fine thread, can’t recall the size anymore I think it was a 10mm and the finest threads. I called HI Nu Tek Inc in sarasota fl and the guy cleaned the threads for me for free.

I learned not to remove ISIS cranks with my old non ISIS crank puller.


if they both go in the same distance of approx 2 threads, the threads and look damaged and from what someone said that it’s a funny fine thread then id suggest the bolts are a different thread. If it was me and i couldnt find the correct bolt then id be tempted to drill and tap it to a slightly larger size that i had a bolt for. but that is me and i have a decent workshop and no decent bike shops around!



I’ve seen several posts regarding stripped threads. Check out a thing called a heli-coil. It’s a bit of an investment, but it’s a really easy thing to master and you retain the same size threads. You drill out the the old threads, tap it for the heli-coil, intstall the heli-coil, and you have new threads that are as strong or stronger than the originals.

It’ll work as well on any part of a uni as it does on stripped spark plugs threads, engine case threads or whatever. You can pick up sets at any auto parts store for just about every thread size.

Before doing anything, find out the right bolt for your hub. Don’t drill, tap, force, or mangle anything before you at least know what is supposed to go in there. Any well stocked machine shop will have all the metric bolts, taps, and thread gauges to determine what belongs in that hub if you can’t find out from some other source. When you find out what the right size bolts are, buy them and try them. If the correct bolts don’t work, then first chase the threads with the correct tap. If the threads won’t clean up decide where to go from there. Over drilling your hub to put in a larger sized bolt or Helicoil will weaken it.

Why do you think the KH bolts will fit the Koxx hub? If Koxx isn’t Isis why would would the bolts be the same size? Has anyone else successfully fitted KH bolts into a Koxx hub? What happened to the original Koxx bolts? Don’t the Koxx and the Koxx light hub fit different sized bolts, which hub do you have?

Lots of questions, but maybe you are trying to fit a square peg into a round hole.


This is all stuff I’m trying to figure out but no one seems to have the answers, I suppose I’ll have to email Koxx. The hub is from before the light hub came out so I assume that means its just the standard reinforced hub.

Thanks for the advice Harper, I wasn’t planning on doing anything until I figured out what bolt it needs.

According to the Koxx website the 12mm bolts fit the standard hub and the 15mm fit the Light hub so there is a really obvious difference in size between the Koxx bolts.

Kris Holm bolts are also 12mm.


Would that then also mean that the threads are the same?

No. Extra fine metric threads are not as common as SAE fine threads but they do exist. Sorry I don’t know the pitch of either one of those bolts. I hope you can find out without having to take it somewhere or buy a thread gauge.

I just had Spencer verify that his KH bolt fits perfectly into his Koxx hub. So unless over the years they’ve changed the thread (the one I have is older than his) it should be able to fit the KH ISIS bolts fine.

So it may not have been the greatest decision but I decided to just be a man about it and force it in there. I was able to thread both cranks on completely but when I took out the bolt there were some very fine strips of metal in the threads which is never very comforting. Should I be worried about that? Have I just carved myself a new path? Is that so bad?

EDIT: It was the correct bolt size, I’m just not quite sure what was going on in there.