Bicycle Mechanics - seatpost clamp to hold threadless steerer?

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jackie o
05-23-07, 01:53 AM
Is it possible to set up a 1" threadless fork this way: a 1" threadless headset and then a 25.4 mm seatpost clamp above that where the threadless stem ordinarily would be to hold the steerer in place; then leave out the star-nut and insert a quill stem into the top of the steerer? The steerer in question is long enough, and does have a 22.2 mm inner diameter, so the quill would fit.

The main issue would be whether the seatpost clamp would be enough to hold the fork in place. I'd rather not learn that the hard way!

Another issue would be how to get the seatpost clamp tight against the headset without a star-nut to pre-load it, but maybe there's a way to do it?

Has anybody seen this done, or have an opinion? Feel free to tell me it's a horrible idea. (I know simply using a threadless stem is easier, but the steerer is just a wee bit too short for that). I'm grateful for any insights.

Thanks!


Stacey
05-23-07, 03:20 AM
Why? <shakes head>

How much is a 'wee bit'?

Boss Moniker
05-23-07, 04:48 AM
I have seen this done before, although the clamp was in place of a whole bunch of spacers, so that the stem could be moved up and down quickly and without adjusting the headset. I don't know how it turned out.

You would, in fact, have trouble tensioning the headset.. I'm sure there could be some workaround, but keeping the star-nut would be a lot easier.


KevinF
05-23-07, 04:59 AM
I have seen this done before, although the clamp was in place of a whole bunch of spacers, so that the stem could be moved up and down quickly and without adjusting the headset. I don't know how it turned out.

You would, in fact, have trouble tensioning the headset.. I'm sure there could be some workaround, but keeping the star-nut would be a lot easier.

Sheldon has a picture of a spacer-less setup on his site: http://www.sheldonbrown.com/handsup.html

tellyho
05-23-07, 01:17 PM
I love it. It would be a pain to dial in, but I think it's totally doable.

wroomwroomoops
05-23-07, 01:51 PM
I have seen this done before, although the clamp was in place of a whole bunch of spacers, so that the stem could be moved up and down quickly and without adjusting the headset. I don't know how it turned out.

Isn't that exactly what the Speedlifter(TM) does?

HillRider
05-23-07, 09:39 PM
I believe there is a locking collar intended for use with travel bikes so the stem/bars could be removed for packing without having the fork drop out. It is designed for the job and should be better than a seatpost collar.

The initial headset adjustment could be made using an expansion plug to develop the preload and then removed afterward to allow the quill to be inserted.

cedricbosch
05-24-07, 06:33 AM
I believe there is a locking collar intended for use with travel bikes so the stem/bars could be removed for packing without having the fork drop out. It is designed for the job and should be better than a seatpost collar.

The initial headset adjustment could be made using an expansion plug to develop the preload and then removed afterward to allow the quill to be inserted.

Correct

jackie o
05-24-07, 04:32 PM
Correct
Is this locking collar different from the Speedlifter? Do you know where I could find it? If there's a part made special that's not too expensive, I'd feel more comfortable using that than a seatclamp.

Thanks for the feedback everyone. I may try the seatpost clamp (pre-loading with the expanding nut) and then ride around very slowly for a little while to see if it begins to loosen. Sheldon Brown's description says he doesn't recommend trying it with 1" steerers, but I'm not sure why. Maybe he meant it's not a good idea to have a 1" steerer sticking up as far as the one in his picture b/c it's not as stiff as a 1 1/8".

If it doesn't work I'll just bite the bullet and spend money getting the thing threaded or buying another fork (I know, I know - threading threadless forks is a risky business, but I've seen this model fork threaded and ridden the snot out of with no trouble, I've talked to the manufacturer, and I live near Harris Cyclery in Boston, who can do a competent job). If the work-around is successful, I'll report.