Anyone on this forum familiar of modding the Grubee HD axle to accept a ISO freewheel


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6:12 PM
May 22, 2008
Hello forum members,

I have a model# 1 Grubee HD axle kit(including 48 tooth sprocket,sprocket freewheel,and band brake) that I would like to modify to accept an ISO thread-on 5-6 speed freewheel(Shimano MegaRange preferred, or Regina American 1992),but have no idea how to accomplish this machine work;I
have seen some posts regarding chasing the Grubee axle cw freewheel threads with an ISO threaded freewheel, but would like to know if there are any other alternatives(other than replacing my current rear hub with a disk brake version to mount a sprocket by an adapter)???:confused:

This Grubee axle has NOT been installed ,or modified yet, but there has to be a way to chase/modify the cw freewheel threads!:unsure:

Thanks in advance for a reply!!
Last edited:
...I know you post a very months ago, maybe this will help someone else.

I settled for a single speed Freewheel and you will have to (if want easy route) get the Chinese threads (I think they are imperial!?) on a freewheel for the HD axle. Only two I have tracked down and prefer the 18tooth

Or the 15 or 16tooth from

My 2nd build will not go this route.
2 possible routes to explore. Try a bicycle shop. They may have a die to re-thread it. The other is a regular ol' machine shop. Either way it will probably cost more than the hub.
Good luck.
Isn't the ISO freewheel is quite a bit smaller than the imperial, though? You can get 14T metric thread freewheels, whereas with imperial, 16T is about as small as it gets.
well you need to meet some old bike hoarder and maybe he will have a wheel that would take no major mods to fit.
Or you may come home with better bike for free:whistle: