where can i get a fork steerer threaded?

[Dolan Halbrook]

Hi all,

I recently picked up a Waterford touring fork for my Gunnar Crosshairs (my all-around bike) to
replace the stock fork. It's a little beefier and has more eyelets but has the same geometry, which
is what I wanted. The shop was willing to give me a good deal on it considering someone had ordered
it and never picked it up. I'm guessing it's been laying about for a while.

The only issue is that the steerer is longer than my current one. It's a threaded steerer, and I'd
like to make it the same height as mine (a la hacksaw) and get some threads put on it farther down
the steerer tube. I could probably run it as threadless but I really like my Mavic headset and
I'd like to be able to easily switch back to the original fork if desired.

Do most shops have the equipment to do this (thread a steerer tube) ? If not, where would I get
something like this done (I'm in SF, CA).

Thanks, Dolan

 

[Mike Jacoubowsk]

> Do most shops have the equipment to do this (thread a steerer tube) ? If not, where would I get
> something like this done (I'm in SF, CA).

Dolan: If you're talking about adding more than a cm of thread, very few shops have the proper
tooling for the job. They may think they do, but if they're talking about running a standard die to
cut new threads, and cutting enough so that they no longer have original threads as a guide, the new
threads will be very low quality.

Best way to add a significant amount of threading to a fork is on a lathe, which is something a
frame builder is more likely to have.

If the fork is long enough, going threadless may be reasonable. True, you won't be able to switch
back and forth with your original, nor can you use your Mavic headset, but a decent headset and stem
aren't very expensive, and they're a lot easier to adjust.

--Mike-- Chain Reaction Bicycles www.ChainReactionBicycles

"Dolan Halbrook" <[email protected]> wrote in message news:1052776213.696465@sj-nntpcache-5...
> Hi all,
>
> I recently picked up a Waterford touring fork for my Gunnar Crosshairs (my all-around bike) to
> replace the stock fork. It's a little beefier and has more eyelets but has the same geometry,
> which is what I wanted. The shop was willing to give me a good deal on it considering someone
> had ordered
it
> and never picked it up. I'm guessing it's been laying about for a while.
>
> The only issue is that the steerer is longer than my current one. It's a threaded steerer, and I'd
> like to make it the same height as mine (a la hacksaw) and get some threads put on it farther down
> the steerer tube. I could probably run it as threadless but I really like my Mavic headset and
> I'd like to be able to easily switch back to the original fork if desired.
>
> Do most shops have the equipment to do this (thread a steerer tube) ? If not, where would I get
> something like this done (I'm in SF, CA).
>
> Thanks, Dolan

 

[Robert Quindazz]

On Mon, 12 May 2003 22:48:34 GMT, "Mike Jacoubowsky/Chain Reaction Bicycles"
<[email protected]> wrote:

>> Do most shops have the equipment to do this (thread a steerer tube) ? If not, where would I get
>> something like this done (I'm in SF, CA).
>
>Dolan: If you're talking about adding more than a cm of thread, very few shops have the proper
>tooling for the job. They may think they do, but if they're talking about running a standard die to
>cut new threads, and cutting enough so that they no longer have original threads as a guide, the
>new threads will be very low quality.
>
I agree that the threads will be of lower quality than those done by the factory. But, given their
size and mission, the threads cut with a die will work just fine. They are under a minimum of stress
as they only set the preload on the headset bearing, the actual load of riding being born by the
bearings themselves. I have performed this operation a number of times with success.

That said, if you can go threadless, now is a good time.

Bob

 

[Mike Jacoubowsk]

> I agree that the threads will be of lower quality than those done by the factory. But, given their
> size and mission, the threads cut with a die will work just fine. They are under a minimum of
> stress as they only set the preload on the headset bearing, the actual load of riding being born
> by the bearings themselves. I have performed this operation a number of times with success.

Having seen a number of forks fail at the end of their threaded section, I'm not so convinced that
this area is under minimal stress, or that the quality of threading is irrelevant.

--Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com

 

[Sheldon Brown]

Mike Jacoubowsky wrote:
>>I agree that the threads will be of lower quality than those done by the factory. But, given their
>>size and mission, the threads cut with a die will work just fine. They are under a minimum of
>>stress as they only set the preload on the headset bearing, the actual load of riding being born
>>by the bearings themselves. I have performed this operation a number of times with success.
>
>
> Having seen a number of forks fail at the end of their threaded section, I'm not so convinced that
> this area is under minimal stress, or that the quality of threading is irrelevant.

This seems more common on wedge-type stems than on the older expander type, because the wedge puts a
more concentrated stress on one part of the steerer.

I somewhat blame the CPSC for this. They seem to have inculcated the idea that stems should be
installed tighter than is really necessary, for some imagined safety improvement.

Many mechanics do overtighten stems, which, in combination with excess threading, can certainly lead
to such failures.

A properly installed stem should allow the bars to rotate if turned forcefully with the wheel held
by the knees. It will never slip in actual riding, but in the event of a fall, the bar should be
able to turn rather than bending.

I sometimes do install stems with the wedge in the threads on my own bikes, but when I do so, I
grind a bit of a radius on the bottom edge of the wedge to reduce the risk of concentrating stress
parallel to the threading.

Sheldon "Tight Enough, But Not Too Tight" Brown
+----------------------------------------------------------------+
| Anyone who cannot cope with mathematics is not fully human. | At best he is a tolerable
| subhuman who has learned to wear | shoes, bathe, and not make messes in the house. | --Robert
| A. Heinlein |
+----------------------------------------------------------------+ Harris Cyclery, West Newton,
Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts
shipped Worldwide http://captainbike.com http://sheldonbrown.com

 

[Mark Hickey]

Sheldon Brown <[email protected]> wrote:

>A properly installed stem should allow the bars to rotate if turned forcefully with the wheel held
>by the knees. It will never slip in actual riding, but in the event of a fall, the bar should be
>able to turn rather than bending.

This is one of the advantages of a threaded stem, IMHO. In the event I fall in such a way as for Mr.
Liver to meet Mr. Handlebar, I'd prefer that the former wouldn't have to bend the latter to move it
out of the way. Much better Mr. Stem slips.

>I sometimes do install stems with the wedge in the threads on my own bikes, but when I do so, I
>grind a bit of a radius on the bottom edge of the wedge to reduce the risk of concentrating stress
>parallel to the threading.

Good idea!

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame

 

[Gary Young]

Sheldon Brown <[email protected]> wrote in message
news:<[email protected]>...
> Mike Jacoubowsky wrote:
> > Having seen a number of forks fail at the end of their threaded section, I'm not so convinced
> > that this area is under minimal stress, or that the quality of threading is irrelevant.
>
> This seems more common on wedge-type stems than on the older expander type, because the wedge puts
> a more concentrated stress on one part of the steerer.

<snip>
>
One of the Rivendell Readers argued just the opposite -- that wedges are safer than expanders. If I
remember correctly, Grant Peterson's argument was that the wedge jams against the steerer in two
places, at the top of the wedge and at the very bottom of the quill. That means the clamping force
is distributed over two points and two separate threads on the steerer, which presumably means that
the magnitude at each point need be less.

Grant also argued that the wedge would be safer in the event of a failure. The expander touches the
steerer at one thread. When that thread breaks, there's nothing for the expander to hold on to. The
wedge-type stem touches the steerer at two threads. If one thread breaks, it's still holding on to
the other thread. (I'm not sure that would help if it's the lower thread that breaks.)

I'm not endorsing this, just throwing it out for comment.