Re: [CR] Lengthening a fork steerer tube, how to?

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In-Reply-To: <E1IjRdX-0002BZ-3a@elasmtp-mealy.atl.sa.earthlink.net>
References: <MONKEYFOODe3N4vBlcI00000fdf@monkeyfood.nt.phred.org> <C33FF8E5.9C41%fatticbicycles@qtm.net>
From: "James Valiensi" <valiensi@mac.com>
Subject: Re: [CR] Lengthening a fork steerer tube, how to?
Date: Sat, 20 Oct 2007 21:34:23 -0700
To: Mark Stonich <mark@bikesmithdesign.com>
cc: classicrendezvous@bikelist.org
cc: classicrendezvous@bikelist.org

Hullo, I would never lengthen a steerer tube. I'd replace it by removing the original one. Having this part of the bike fail is quite disastrous, and I would not take on the risk. James Valiensi Northridge, CA On Oct 20, 2007, at 8:38 PM, Mark Stonich wrote:
> At 10/20/2007 06:26 PM -0400, Doug Fattic wrote:
>> The cut off needs to be long enough above where the taper stops
>> so the sleeve is long enough so it can have enough support in the old
>> steerer. The sleeve will need to stick an equal distance into the
>> new
>> steerer. Now this sleeve needs to be down far enough from the top
>> so it
>> doesn't interfere with the insertion of the stem. If those
>> conditions can
>> be met, then part of the old steerer can be cut off and a new
>> longer section
>> of steerer brazed back on.
>
> Doug,
> Sounds good, but how long is "Long enough" for the overlap between
> sleeve and steerer?
> Do you use silver or bronze/brass?
> Do you drill any holes into the steerer halves to feed filler into?
>
> The steerer on my 1957 Raleigh RRA Moderne has two places where the
> conical wedge stem was tightened so much the steerer isn't just
> bulged, but creased. It has the Raleigh tubular fork crown and I
> don't see any way to non-destructively remove the chromed
> "thimbles" from the ends of the crown. So, just replacing the
> steerer doesn't seem to be an option.
>
> Fortunately the steerer is fairly long, (23" frame) and I need my
> stems as high as they'll go. I'll have to decide whether to use a
> steerer from a Raleigh donor fork to get 26tpi threading or go to
> 24tpi and use a, much better, modern headset.
>
> BTW Thursday I replaced a steerer on a rather unique "fork".
> http://bikesmithdesign.com/projects/swing-bike-fork.jpg 35 Kb.
> It's for one of those trick bikes from the '70s with a fork at each
> end.
> See one in action here;
> http://www.youtube.com/watch?v=vUcn2VpAnqc&mode=related&search=
>
> Mark Stonich;
> BikeSmith Design & Fabrication
> 5349 Elliot Ave S. - Minneapolis. MN 55417
> Ph. (612) 824-2372 http://bikesmithdesign.com
> http://mnhpva.org