Re: Cable Routing Problem w/ Riv's MicroShift FDer on AHH

[Rex Kerr]

Update:  Lowered the fder, lower than I'd usually put it, but still clearing the top ring, and it doesn't interfere anymore, but it's still darn hard to operate.  Any ideas why?

On Jul 10, 2011 2:30 PM, "Rex Kerr" <rex...@gmail.com> wrote:
> I was working on assembling my new AHH today and ran into a little problem
> with the front derailleur. I have installed dozens
> of front derailleurs before without a problem, even having to do strange
> things like pinch cable housing between a kickstand plate and the downtube
> to use direct pull derailleurs on bikes that weren't designed for them, and
> never had this kind of problem.
>
> Here's a picture of the routing issue:
>
> http://imgur.com/arxLD
>
> The cable wants to rest right on the pivot's rivet. Sometimes it snaps
> behind the pivot and gets stuck. I've tried raising and lowering
> the derailleur, rotating it to change the alignment, monkeying with the
> limit screws, everything that would make it work poorly, and even if I can
> get it not to interfere (much -- the picture is the best I've gotten)
> the derailleur takes a significant amount of force to operate, far more than
> any other that I've ever used.
>
> Has anybody else run into this problem? Does anybody else have this
> particular derailleur on their AHH that they'd be willing to photograph so
> that I can see how the cable runs?
>
> I'd call Riv for advice, but they're closed today, so I might end up having
> to call them tomorrow.
>
> Thanks!
> -Rex

[Rex Kerr]

[Michael Glaser]

Rex,

I don't have that issue on my Hilsen, but on another bike (with a SRAM front derailleur) the FD cable touches the pivot -- same as yours.  I slipped a short length of plastic tubing over the cable so that it would "roll" over the derailleur pivot without too much interference.  That works surprisingly well, and I don't have any running problems.

Michael Glaser

[William]

Two things, maybe three things come to mind on why a front derailer is really hard to operate. 

1.  The lever arm from cable bolt to pivot is really short.  This helps determine how much lever travel imparts how much derailer travel.  These lever arms got shorter for brifters.   The shorter this lever arm is, the harder it is to actuate
2.  The spring itself is really strong.  The stronger the spring, the harder to shift up to the bigger ring.  A stronger spring doesn't get you a whole lot on the plus side
3.  You have the cable running two close to the anchor bolt, or under it?  From the picture you did post it looks like the cable is kind of going straight up at the bolt.  Many derailers of this type have a nub on the female side of the anchor bolt assembly.  The intent is for the cable to route OVER that nub, not under.  On some older derailers being retrofitted with brifters, some mechanics found that running under the nub got you better actuation.  Under the nub makes that lever arm shorter and harder to actuate.  Over the nub makes that lever arm effectively longer, and easier to actuate. 

[Rex Kerr]

Update2:  I'm stupid.

Just had a moment of inspiration...  Looking at the tiny pictures in the tech documents on the MicroShift website I suddenly realized that the little tab next to the cable binder screw wasn't part of the retention mechanism as I initially thought, and that the cable should go over it, rather than between it and the bolt.  Sure enough, it's much easier to shift now!

-Rex

[Eric Norris]

Reading the instructions? What an interesting idea. I will have to try that sometime.

--Eric "Still Can't Remember How to Set the VCR" Norris

Sent from the iPad 2

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[Philip Williamson]

When I find myself reading the instructions, I know that the item is
either long gone, or completely obselete.
The other thing I do is throw away the instructions and/or box right
before I find out that the obsolete item I still have is now a prized
collectible...

Philip

Philip Williamson
www.biketinker.com

On Jul 11, 8:58 am, Eric Norris <campyonly...@me.com> wrote:
> Reading the instructions? What an interesting idea. I will have to try that sometime.
>
> --Eric "Still Can't Remember How to Set the VCR" Norris
> Sent from the iPad 2
>

> On Jul 10, 2011, at 11:55 PM, Rex Kerr <rexk...@gmail.com> wrote:
>
> > Update2:  I'm stupid.
>
> > Just had a moment of inspiration...  Looking at the tiny pictures in the tech documents on the MicroShift website I suddenly realized that the little tab next to the cable binder screw wasn't part of the retention mechanism as I initially thought, and that the cable should go over it, rather than between it and the bolt.  Sure enough, it's much easier to shift now!
>
> > -Rex
>

> > On Jul 10, 2011 3:07 PM, "Rex Kerr" <rexk...@gmail.com> wrote:
> > > Update: Lowered the fder, lower than I'd usually put it, but still clearing
> > > the top ring, and it doesn't interfere anymore, but it's still darn hard to
> > > operate. Any ideas why?

[Rex Kerr]

:-)  Too bad it didn't come with instructions and I had to find them with some googlefu on a broken website that only worked when directly linking to the PDF files.

The search that worked:   site:microshift.biz filetype:pdf front derailleur

[Rex Kerr]

Ding ding ding, we have a winner! :-)  #3 was exactly my problem.  I was thinking of the little nub as being analogous to how the old pinch washers used to have a little flap that went down next to the cable (hard to describe).

As for #2... I've never understood why the spring were so darn strong on front derailleurs.   It still requires more force than some of my older derailleurs, even when set up correctly due to the very short action arm.

-Rex

 Too bad you didn't reply earlier yesterday. :-)

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