threaded steerer tubes

[shankldu]

is it possible to clamp a one inch stem right onto the threads of a inch threaded steerer tube after tightening the nut down ontop of the stem.

[Joachim]

I thought that is what threadless forks are for....

[christian]

No.

[thwart]

It's possible, as long as you don't ride the bike after doing so. :D

[Stan Lee]

Don't do it! It may work but it's not safe IMO.

[CNY rider]

In the history of bad ideas, this idea ranks highly.
Heed the advice above.

[Hindmost]

There are adapters that clamp a threaded steerer like a quill and present an attachment point for a threadless stem. Presumably a safe way to do this.

[EricEstlund]

Do you mean a quill to threadless adapter? It expands inside the threaded steerer like a quill with a threadless portion above the headset for threadless stems.

http://lh3.googleusercontent.com/public/soMx4zOSwwmC2OdOXBK3YFhQdingqHRHFpqVzmKJToVBY-mc7fhvH0-LeSG8DmWIsp37PhQ8NJPUqvTsyKkleAi5xIAp8gT7QJPzlZfvy p-1Qge-QRcvqiG4d3YVTQStcRQ1utnnCpd3TfFVqUbSsVKIVw2RNQQJ6q zLLY7fWA

The key here is that the threaded portion of the steerer is still internally supported by a quill.

[Hindmost]

Yep, that is it. Don't know if that answers the OP's question.

[Ralph]

is it possible to clamp a one inch stem right onto the threads of a inch threaded steerer tube after tightening the nut down ontop of the stem.

Most stems for threadless forks I see are 1 1/8". I don't see why you couldn't put the adapter/shim over the threaded part of fork, and then put a 1 1/8 stem over that.

Most threaded forks are cut just below the head set stack, so there is no threaded fork left to clamp to. So you use an adaptor, quill stem like, like mentioned above.

But if you have enough fork above head set to clamp to, use a shim and 1 1/8 stem, I don't see why not.

SHIM Picture http://www.wiggle.co.uk/ritchey-alloy-stem-shim/

[thwart]

Most stems for threadless forks I see are 1 1/8". I don't see why you couldn't put the adapter/shim over the threaded part of fork, and then put a 1 1/8 stem over that.

Most threaded forks are cut just below the head set stack, so there is no threaded fork left to clamp to. So you use an adaptor, quill stem like, like mentioned above.

But if you have enough fork above head set to clamp to, use a shim and 1 1/8 stem, I don't see why not.

SHIM Picture http://www.wiggle.co.uk/ritchey-alloy-stem-shim/
I dunno... shim or no, I've heard the threading weakens that section of the tube, and it's not meant to have a stem clamped to it.

Unsafe at any speed... as Ralph used to say.

[Ralph]

I dunno... shim or no, I've heard the threading weakens that section of the tube, and it's not meant to have a stem clamped to it.

Unsafe at any speed... as Ralph used to say.


I agree. Although I assumed the threaded fork was steel. I don't think I have ever seen a threaded steel fork with enough threaded fork above head set to clamp to. But maybe a used fork cut and threaded for an extremely tall head tube might be out there somewhere.

I would just use the threaded fork cut to head set height, and then use the quill adapter. They are cheap on E bay.

[shankldu]

Yea i have a fork that has a long enough tube abve the head tube,and i guess i have to much faith in steel threadless forks are out here but i didnt want to make the investment for a beater winter commuter .

[cp43]

Yea i have a fork that has a long enough tube abve the head tube,and i guess i have to much faith in steel threadless forks are out here but i didnt want to make the investment for a beater winter commuter .

You can get a new threaded to threadless adapter for less than $15, IMHO, it's worth it for the peace of mind.

http://aebike.com/product/profile-conversion-22.2mm-1-fork-to-25.4mm-1-threadless-stem-sku-sm6400-qc30.htm

[christian]

What's the problem with a quill stem?

[oliver1850]

Threads are a definite stress riser when there's a bending load put on a tube. This is the situation you have with them extending above a threadless headset. The load you put on the bars is increased in the steerer by the extension of the stem. The threads concentrate the load in a small area of the tube, which over time will result in a crack, leading to the steerer breaking near the top of the headset. The same principle applies to handlebars. Any scratch, especially one that crosses the tube, weakens it. The closer the scratch to the stem, the more likely to result in a crack. This is why you shouldn't trim bar tape against the bar with a knife.

If the steerer is so long that the unthreaded portion extends through the headset, spacers, and well up into the stem I wouldn't be afraid to use it. A short section of threads at the top where there is virtually no bending load should be safe.

The best thing to do with the fork is use a threaded headset. It it's too long, you can have it threaded down farther and cut to the right length. Then use either a quill stem if you want to use a 25.4, 26 or 26.4 bar; or a quill adapter if 31.8. You can use the quill adapter for the other diameters as well.

Long 1" forks are getting harder to find. If it's a good fork, I'd recommend you find someone who needs that length, and find the right length for your frame. Nashbar's threaded carbon fork is on sale right now for $70