Stronger/faster MTB f.deraileur?

[Hank]

On Mar 8, 1:30 pm, landotter <[email protected]> wrote:
> On Mar 8, 12:04 pm, A Muzi <[email protected]> wrote:
>
> > Top pull front changers have their own problems; generally stiffer
> > action to the outside and a different set of cable issues.
>
> I'm new to top-pull, but it seems they provide a nice snappy shift to
> granny under load--other than that, I find them ugly, and they clutter
> the cluster, making mounting fenders a hassle. I'm assuming their
> existence is some sort FS mtb clearance issue. Action to the outside
> seems fine with RF shifters, might be a bit hard with GS.

That's top-swing, not top-pull. Near as I can tell, they exist because
traditional down-swing/high-band FDs had problems with waterbottle
cage mounts on smaller frames.

 

[Jose]

On Sat, 08 Mar 2008 15:20:26 -0600, Ben C <[email protected]> wrote:

>I get them sticking quite often with all the mud around in the winter.
>I've developed a knack of just giving the FD a gentle inwards kick with
>my heel without taking my feet off the pedals.

I like that "if anything else fails" kind of approach! LOL

Best
Jose

 

[Jose]

On Sun, 9 Mar 2008 00:11:16 -0800 (PST), Hank <[email protected]>
wrote:

>That's top-swing, not top-pull. Near as I can tell, they exist because
>traditional down-swing/high-band FDs had problems with waterbottle
>cage mounts on smaller frames.


Hre we go playing with words... Shimano and similar, don't run out of
new products, just new apropriate names for them :-(

OK, so what's the fiference between top swing, and top pull?

Best,
Jose

 

[Lou Holtman]

Jose wrote:
> On Sun, 9 Mar 2008 00:11:16 -0800 (PST), Hank <[email protected]>
> wrote:
>
>> That's top-swing, not top-pull. Near as I can tell, they exist because
>> traditional down-swing/high-band FDs had problems with waterbottle
>> cage mounts on smaller frames.
>
>
> Hre we go playing with words... Shimano and similar, don't run out of
> new products, just new apropriate names for them :-(
>
> OK, so what's the fiference between top swing, and top pull?
>
> Best,
> Jose


Top swing: cage is above the mountingband on the seattube
Down swing: cage is under the mountingband on the seattube

Top pull: cable comes from above (ATB style)
Down pull: cable come from under the front derailleur (Road bike style)

Lou, what's in a name

 

[Hank]

On Mar 9, 5:23 am, Lou Holtman <[email protected]> wrote:
> Jose wrote:
> > On Sun, 9 Mar 2008 00:11:16 -0800 (PST), Hank <[email protected]>
> > wrote:
>
> >> That's top-swing, not top-pull. Near as I can tell, they exist because
> >> traditional down-swing/high-band FDs had problems with waterbottle
> >> cage mounts on smaller frames.
>
> > Hre we go playing with words... Shimano and similar, don't run out of
> > new products, just new apropriate names for them :-(
>
> > OK, so what's the fiference between top swing, and top pull?
>
> > Best,
> > Jose
>
> Top swing: cage is above the mountingband on the seattube
> Down swing: cage is under the mountingband on the seattube
>
> Top pull: cable comes from above (ATB style)
> Down pull: cable come from under the front derailleur (Road bike style)
>
> Lou, what's in a name

Yeah, what he said.

 

[A Muzi]

> Hank <[email protected]> wrote:
>> That's top-swing, not top-pull. Near as I can tell, they exist because
>> traditional down-swing/high-band FDs had problems with waterbottle
>> cage mounts on smaller frames.

Jose wrote:
> Hre we go playing with words... Shimano and similar, don't run out of
> new products, just new apropriate names for them :-(
> OK, so what's the fiference between top swing, and top pull?

Top Swing is a Shimano designed mechanism wherein the moving
parallelogram is above the mounting clamp (i.e. most newish non-road
models) Here's one:
http://www.cyclelink.com.au/images/fd-m570-e.jpg

Top Pull are designs (Shimano, Campagnolo, Suntour etc) in which the
gear wire attaches from above, not below (under the BB).

Bottom Pull is what you grew up with, if you are old:
http://www.yellowjersey.org/3RDM4.JPG
(BP replaced the quite dependable swing-arm controls before gear wires)

There were at one time two intermediate designs between BP and TP. One
was with a pulley anchored to the back of the seat tube to use a
bottom-pull changer with a from-above gear wire. The other used an
adapter to stop a gear casing at the anchor of an otherwise BP changer
making it an effective TP design. Neither are current so far as I know.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Helmut Springer]

A Muzi <[email protected]> wrote:
> There were at one time two intermediate designs between BP and TP.
> One was with a pulley anchored to the back of the seat tube to use
> a bottom-pull changer with a from-above gear wire.

Cyclocross frames still might have a boss for that pulley, to
accomodate road BP front derailleurs...

--
MfG/Best regards
helmut springer panta rhei

 

[Peter Cole]

Jose wrote:
> On Sat, 08 Mar 2008 18:52:06 +0100, Lou Holtman
> <[email protected]> wrote:
>
>> If it hesitates to move
>> there is something serious wrong.
>
> I wouldn't say it hesitates; it just doesn't move inwards enough. It
> presses the chain, but it's only when I'm using the 3rd larger cog, or
> bigger, that it actually changes into the granny chainring.
>
> I tried to adjust the FD to move the chain inwards *past* the granny
> ring (and then work opposite from there to point where it would land
> on the granny ring) and simply couldn't achieve that misaglinement :-(

First, make sure your limit screws are set to give maximum excursion.

Second, make sure the cage is just above the 3rd ring teeth (1-2mm). If
you still can't get enough inward swing to get into the granny reliably,
you can try angling the cage "tail" inward slightly (rotating the clamp).

If your chain line is too far out because of a mismatch between spindle
length and crank, the real solution is a new BB, but I've kludged this
on beaters by shimming the (square taper) spindle/crank interface with
some thin aluminum cut from a can.

 

[Jose]

On Mon, 10 Mar 2008 12:48:22 GMT, Peter Cole <[email protected]>
wrote:

>First, make sure your limit screws are set to give maximum excursion.

They are.


>Second, make sure the cage is just above the 3rd ring teeth (1-2mm).

It is.

> If
>you still can't get enough inward swing to get into the granny reliably,
>you can try angling the cage "tail" inward slightly (rotating the clamp).

Been there, didn't like it much - with the chain on the middle ring,
and smallest rear cog, it would rub on the FD :-(
But I'll give it another try at that, since recently I have brought
the FD downard, closer to the largest ring.

One other tip I read somewhere on the Net, is a bit more drastic:
bending the tip of the FD slighty inwards... Any comments?



>If your chain line is too far out because of a mismatch between spindle
>length and crank, the real solution is a new BB, but I've kludged this
>on beaters by shimming the (square taper) spindle/crank interface with
>some thin aluminum cut from a can.

You mean, like inserting a washer between the crank and the BB
splindle? Ok, I think I'll have to "manufacture" one, since I tried
that before, and couldn't find a washer that would fit - they would
either not slip over the square taper, or go over all the way untill
the BB cage, therefore thighening the BB bearings (I thing (?)).

Thanks a lot!
Jose

 

[Jose]

On Sun, 09 Mar 2008 13:23:47 +0100, Lou Holtman
<[email protected]> wrote:

>Top swing: cage is above the mountingband on the seattube
>Down swing: cage is under the mountingband on the seattube

Ah... that should explain the diferences I've seen in Shimano's web
site!
I get the idea that in a downswing model, the cage is capable of
getting closer to the seat tube, or the BB - am I wrong?



>Top pull: cable comes from above (ATB style)
>Down pull: cable come from under the front derailleur (Road bike style)

Humm... In my bike, cable travels along the top tube, goes down along
the seat tube, *then* goes under the frame, and finally attaches to
the FD...
So, it' s an ATB bike, with sort of a road bike FD cable path ;-| I'd
prefer a simpler, straighter path.

I'll have to try if my FD would work without the cable bend below the
frame, although I imagine a bigger advantage at using a downswing type
FD

Thanks a lot!
Jose

 

[Jose]

On Sun, 09 Mar 2008 14:59:20 -0600, A Muzi <[email protected]>
wrote:

>Top Swing is a Shimano designed mechanism wherein the moving
>parallelogram is above the mounting clamp (i.e. most newish non-road
>models) Here's one:
>http://www.cyclelink.com.au/images/fd-m570-e.jpg

Right. Mine's very similar to this one (top swing, I assume)
http://www.chainreactioncycles.com/Models.aspx?ModelID=825 as I
looking from above, I can clearly see a dark plastic (?) plate, which
is held to FD by the adjusting screws, and takes about 1/2 an inch
space between the FD cage, and the seat tube.

I start to get the feeeling I might do better with something like this
one (down swing, I assume)
http://www.chainreactioncycles.com/Models.aspx?ModelID=3407 , hoping
it would allow me to get the FD cage closer to the seat tube

If I'm getting this right, please tell me, so that I might understand
why my LBS immediatelly told me I needed a longer BB - and they sold
and fited one such BB in my bike - but never mentioned a diferent kind
of FD.
(I had just fited a new hollow BB, UN-7x, I think, and next paid for
an obscure - longer - solution, which hasn't worked the way I wished
it would.)

Best,
Jose

 

[Jose]

PS - This happened after I changed cranks, and the new ones seemed to
go in a lot closer to the BB/seat tube.


If I'm getting this right, please tell me, so that I might understand
why my LBS immediatelly told me I needed a longer BB - and they sold
and fited one such BB in my bike - but never mentioned a diferent kind
of FD.
(I had just fited a new hollow BB, UN-7x, I think, and next paid for
an obscure - longer - solution, which hasn't worked the way I wished
it would.)

Best,
Jose

 

[Michael Press]

In article <[email protected]>,
[email protected] (Jose) wrote:

>
> One other tip I read somewhere on the Net, is a bit more drastic:
> bending the tip of the FD slighty inwards... Any comments?

Know exactly what you are doing. Think about all details.
Sleep on it. If you consider it a very good idea, then do it.

--
Michael Press