Re: Changing forks on a MTB



T

Taka

Guest
On Sun, 31 Jul 2005 21:24:31 +0100, Chris Eilbeck
<[email protected]> wrote:

>I've never done this before but I'm guessing it's a pretty
>straightforward job. I'd rather do it myself than get my LBS to do it
>if I can. Are there any gotchas I should be aware of? The forks seem
>to have recently developed about 1/2" of unsprung travel when I lift
>the front of the bike off the ground so I'm going to replace them with
>some rigids.
>
>FWIW I've got a 1994 Saracen Sahara MTB (front suss only) with road
>tyres which I use for commuting, general pootling around and the odd
>20-30 mile jaunt, mainly on roads but the occasional towpath.
>
>Yes, I know I could use this as an excuse to buy a new bike ;)
>
>Chris


I've done it...once!
I performed this task on an alloy steering tube so if your new tube is
carbon fibre my advice may be wrong!

You won't always need to cut the tube but if you do:
1) Cut new fork steerer using a hacksaw. Use an old (or unused)
headset spacer and tape it to steering tube so you keep a straight
cut.
2) Smooth cut tube using dremel or sandpaper.
2a) Use mask + goggles when you do all of this.

3) Either push the starfangled nut out of the old tube and reuse it OR
get a new one. When you take it out, push it down the tube, not UP
like I tried on my first attempt :-(
4) I think there might be some sort of a "starfangled nut pusher tool"
out there but failing this, use the end of a long wrench or something
long and thin enough to tap the nut down the new tube. Do this
carefully so that it goes down straight.
Don't push it down so far that the bolt can't reach it!
5) Reuse (or get new) crown race and gently tap this down to the base
of the new steerer tube.
6) Check headset bearings in case they need replacement.
7) Grease any parts that need to be greased, race bearings, etc.
8) Make sure the tube length is such that the top of the tube is about
3mm below the top of the stem (or same distance below the top of the
top spacer).
9) Screw in top cap so the bar is aligned with the wheels and the unit
is tight.
10) Tighten the stem screws.
11) Done!

Which forks are you going to put on?

Taka
 
in message <[email protected]>, Taka <Taka> ('')
wrote:

> 8) Make sure the tube length is such that the top of the tube is about
> 3mm below the top of the stem (or same distance below the top of the
> top spacer).


Do this /before/ you cut.

> 1) Cut new fork steerer using a hacksaw. Use an old (or unused)
> headset spacer and tape it to steering tube so you keep a straight
> cut.
> 2) Smooth cut tube using dremel or sandpaper.
> 2a) Use mask + goggles when you do all of this.


Angle grinder does all this in one go and is quicker.

> 4) I think there might be some sort of a "starfangled nut pusher tool"


A highly technical tool known in the trade as a 'broom handle'.

> 5) Reuse (or get new) crown race and gently tap this down to the base
> of the new steerer tube.


That's the bit that genuinely does require a specialist tool which your
LBS will have. Get them to do this bit. It will take under five minutes
and your crown race will not get damaged.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; single speed mountain bikes: for people who cycle on flat mountains.
 
"Simon Brooke" <[email protected]> wrote in message
news:[email protected]...
> in message <[email protected]>, Taka <Taka> ('')
> wrote:
> > 5) Reuse (or get new) crown race and gently tap this down to the base
> > of the new steerer tube.

>
> That's the bit that genuinely does require a specialist tool which your
> LBS will have. Get them to do this bit. It will take under five minutes
> and your crown race will not get damaged.


If the headset is knackered and needs replacing some sets use a split lower
crown race that is easy to fit & remove. My FSA has this feature but may be
prohibitively expensive however it would be worth finding out if any
cheaper types have it. It would only be applicable to sealed bearing types I
imagine.
--
Pete
http://uk.geocities.com/[email protected]/P