7" steerer tube into 5" head tube.

[2011softcruise]

Hi to all.

Here's another project I'm tinkering with. I have an older (26" MTB) frame (bare) and springer fork just waiting to be used again (both are 1"). The head tube on the frame is 5" (or a bit more) and the fork steerer tube is 7"+. The threads on the steerer tube don't go far enough for the remaining parts (bearing nut etc.). I've considered the following to remedy the problem:

1. Take the forks to a machine shop and have more threads added.

2. Find an "extension" head set that can reach both the available threads and the bearings.

Any ideas or suggestions is appreciated. There is some metallurgy involved with forks and metals heat up when threaded so I'm unsure if the forks will become brittle after threads are added.

Thanks....................Tom

[trevgbb]

any decent old style LBS should have a fork thread cutting die, shouldn't cost much and no heat will be involved.
You could also consider converting to a threadless A-Head style set up? again a LBS would advise if you are prepared to buy the parts from them.

[JohnV]

My suggestion was going be go to a threadless headset that way you can cut down the steerer tube to fit the head tube, but trevgbb beat me to it.

[DaveM]

I don't think you are supposed to use a threadless ("A-head style") headset on a fork designed for threaded that just doesn't have the threads cut. Especially if the threadless stem would clamp anywhere that there is threads. Recipe for catastrophic failure.

Any decent bike shop can cut extra threads and cut the length down to the right size. Totally standard practice.