esoteric front derailleurs....

On 4 Sep 2006 18:26:11 -0700, "sal bass" <[email hidden]>

Quoted message said:

was there ever a front derailleur made in a TOP PULL variant for ROAD
doubles?

i've seen cross bikes (like the Bontrager CX) that have a pulley
integrated into the backside of the seat tube down by the bottom
bracket shell, that redirects the cable back up to the fixing bolt on
road front derailleurs.

but i don't think i've ever seen a top pull front der. for road
doubles.

Dear Sal,

I found nothing with a quick browse through Berto's "The Dancing
Chain," but I have trouble making sense of many of the drawings.

There were plunger-style front derailleurs from the 1950's from
Simplex and Campagnolo in which the front derailleur cage just moved
sideways horizontally. The ----'s running through the XXXX below
represent the confusingly named "plunger," which plunged sideways, not
up and down:

---XXXXX---| | XXXXX = plunger body
s -------- = plunger rod
s c O | | = front derailleur cage on end of rod
s I O I = inner, smaller front chain-ring
s I O O = outer, larger front chain ring
s c O c = chain
s s = seat tube

XXXXX------| |
s c
s O
s I O
s I O
s O
s c
s O
s

And there were all sorts of odd twist-lever front derailleurs.

Cheers,

Carl Fogel

On 4 Sep 2006 18:26:11 -0700, "sal bass" <[email hidden]>

Quoted message said:

was there ever a front derailleur made in a TOP PULL variant for ROAD
doubles?

i've seen cross bikes (like the Bontrager CX) that have a pulley
integrated into the backside of the seat tube down by the bottom
bracket shell, that redirects the cable back up to the fixing bolt on
road front derailleurs.

but i don't think i've ever seen a top pull front der. for road
doubles.

Dear Sal,

D'oh! I should have searched the archives, not had fun with Berto's
book:

http://groups.google.com/group/rec.bicycles.tech/browse_frm/thread/ab22bd0aae13936a/b144b5b2125ad758?lnk=gst&q=%22top+pull%22&rnum=3#b144b5b2125ad758
or http://tinyurl.com/nmy58

In the short thread above, Peter Chisholm says, "No top pull road
front ders anymore tho. Sachs had one a while ago."

Cheers,

Carl Fogel

Quoted message said:

On 4 Sep 2006 18:26:11 -0700, "sal bass" <[email hidden]>

Quoted message said:

was there ever a front derailleur made in a TOP PULL variant for ROAD
doubles?

i've seen cross bikes (like the Bontrager CX) that have a pulley
integrated into the backside of the seat tube down by the bottom
bracket shell, that redirects the cable back up to the fixing bolt on
road front derailleurs.

but i don't think i've ever seen a top pull front der. for road
doubles.

Dear Sal,

D'oh! I should have searched the archives, not had fun with Berto's
book:

http://groups.google.com/group/rec.bicycles.tech/browse_frm/thread/ab22bd0aae13936a/b144b5b2125ad758?lnk=gst&q=%22top+pull%22&rnum=3#b144b5b2125ad758
or http://tinyurl.com/nmy58

In the short thread above, Peter Chisholm says, "No top pull road
front ders anymore tho. Sachs had one a while ago."

Cheers,

Carl Fogel

And there it is, in Berto's text, though there's no picture:

"In 1996 . . . Sachs front derailleurs got Inverse Action, with the
cable pulling the cage onto the smaller chainwheels and a spring
pushing it onto the larger chainwheels. This good idea was first used
by SunTour in the 1970s."

--p.314, "The Dancing Chain," 2nd edition.

CF

Quoted message said:

Quoted message said:

sal bass said:

was there ever a front derailleur made in a TOP PULL variant for ROAD
doubles?

i've seen cross bikes (like the Bontrager CX) that have a pulley
integrated into the backside of the seat tube down by the bottom
bracket shell, that redirects the cable back up to the fixing bolt on
road front derailleurs.

but i don't think i've ever seen a top pull front der. for road
doubles.

Not a contemporary one that I know of. A brave person could
try grinding a top-pull MTB der to fit a road big ring. Shimano
has made top-pull MTB ders that have capacity up to 48t, which
is about all you need on a cross bike. Either way, unlikely to
index perfectly with road STI levers. You can also get a clamp-on
pulley and use a bottom-pull derailleur.

Quoted message said:

And there it is, in Berto's text, though there's no picture:

"In 1996 . . . Sachs front derailleurs got Inverse Action, with the
cable pulling the cage onto the smaller chainwheels and a spring
pushing it onto the larger chainwheels. This good idea was first used
by SunTour in the 1970s."

--p.314, "The Dancing Chain," 2nd edition.

IIRC, the SunTour reverse action front derailleurs were
bottom pull. A short length of cable housing ran from a
housing stop on the downtube near the BB, bent upward,
and ran up to a stop on the front derailleur. The model
name was "Spirt" (not Spirit):
http://members.jcom.home.ne.jp/suntour/fd/spirt.html

Have one of those buggers on my wifes cannondale tourer, it sucks having the
shifter work in reverse, keep forgeting :-I
Dave
http://www.noweldrecumbent.com

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

Quoted message said:

On 4 Sep 2006 18:26:11 -0700, "sal bass" <[email hidden]>

Quoted message said:

Quoted message said:

Quoted message said:

>was there ever a front derailleur made in a TOP PULL variant for ROAD
>doubles?
>
>i've seen cross bikes (like the Bontrager CX) that have a pulley
>integrated into the backside of the seat tube down by the bottom
>bracket shell, that redirects the cable back up to the fixing bolt on
>road front derailleurs.
>
>but i don't think i've ever seen a top pull front der. for road
>doubles.

Not a contemporary one that I know of. A brave person could
try grinding a top-pull MTB der to fit a road big ring. Shimano
has made top-pull MTB ders that have capacity up to 48t, which
is about all you need on a cross bike. Either way, unlikely to
index perfectly with road STI levers. You can also get a clamp-on
pulley and use a bottom-pull derailleur.

Quoted message said:

And there it is, in Berto's text, though there's no picture:

"In 1996 . . . Sachs front derailleurs got Inverse Action, with the
cable pulling the cage onto the smaller chainwheels and a spring
pushing it onto the larger chainwheels. This good idea was first used
by SunTour in the 1970s."

--p.314, "The Dancing Chain," 2nd edition.

IIRC, the SunTour reverse action front derailleurs were
bottom pull. A short length of cable housing ran from a
housing stop on the downtube near the BB, bent upward,
and ran up to a stop on the front derailleur. The model
name was "Spirt" (not Spirit):
http://members.jcom.home.ne.jp/suntour/fd/spirt.html

Quoted message said:

Quoted message said:

On 4 Sep 2006 18:26:11 -0700, "sal bass" <[email hidden]>

Quoted message said:

was there ever a front derailleur made in a TOP PULL variant for ROAD
doubles?

i've seen cross bikes (like the Bontrager CX) that have a pulley
integrated into the backside of the seat tube down by the bottom
bracket shell, that redirects the cable back up to the fixing bolt on
road front derailleurs.

but i don't think i've ever seen a top pull front der. for road
doubles.

Dear Sal,

D'oh! I should have searched the archives, not had fun with Berto's
book:

http://groups.google.com/group/rec.bicycles.tech/browse_frm/thread/ab22bd0aae13936a/b144b5b2125ad758?lnk=gst&q=%22top+pull%22&rnum=3#b144b5b2125ad758
or http://tinyurl.com/nmy58

In the short thread above, Peter Chisholm says, "No top pull road
front ders anymore tho. Sachs had one a while ago."

Cheers,

Carl Fogel

And there it is, in Berto's text, though there's no picture:

"In 1996 . . . Sachs front derailleurs got Inverse Action, with the
cable pulling the cage onto the smaller chainwheels and a spring
pushing it onto the larger chainwheels. This good idea was first used
by SunTour in the 1970s."

I remember the Suntour ones were not as good as a normal action. You
needed more than a spring to get the chain from 36 to 52 sometimes.

i know about the Sachs ones....they made BOTH a reverse and normal
action front der. braze on only, from what i remember but of the
bunches i've seen....they've all been for triples.

Quoted message said:

Quoted message said:

On 4 Sep 2006 18:26:11 -0700, "sal bass" <[email hidden]>

Quoted message said:

was there ever a front derailleur made in a TOP PULL variant for ROAD
doubles?

i've seen cross bikes (like the Bontrager CX) that have a pulley
integrated into the backside of the seat tube down by the bottom
bracket shell, that redirects the cable back up to the fixing bolt on
road front derailleurs.

but i don't think i've ever seen a top pull front der. for road
doubles.

Dear Sal,

D'oh! I should have searched the archives, not had fun with Berto's
book:

http://groups.google.com/group/rec.bicycles.tech/browse_frm/thread/ab22bd0aae13936a/b144b5b2125ad758?lnk=gst&q=%22top+pull%22&rnum=3#b144b5b2125ad758
or http://tinyurl.com/nmy58

In the short thread above, Peter Chisholm says, "No top pull road
front ders anymore tho. Sachs had one a while ago."

Cheers,

Carl Fogel

And there it is, in Berto's text, though there's no picture:

"In 1996 . . . Sachs front derailleurs got Inverse Action, with the
cable pulling the cage onto the smaller chainwheels and a spring
pushing it onto the larger chainwheels. This good idea was first used
by SunTour in the 1970s."

--p.314, "The Dancing Chain," 2nd edition.

CF

i'm using campagnolo bar cons instead of indexed shimano.

also...the clamp-on pulley did cross my mind...but just for a second.
i can't see clamping on something to a $3000 + custom frame. seems
wrong. and yes the fabricator will integrate one...but that really
isn't the point.

Quoted message said:

Quoted message said:

Quoted message said:

On 4 Sep 2006 18:26:11 -0700, "sal bass" <[email hidden]> wrote:

>was there ever a front derailleur made in a TOP PULL variant for ROAD
>doubles?
>
>i've seen cross bikes (like the Bontrager CX) that have a pulley
>integrated into the backside of the seat tube down by the bottom
>bracket shell, that redirects the cable back up to the fixing bolt on
>road front derailleurs.
>
>but i don't think i've ever seen a top pull front der. for road
>doubles.

Not a contemporary one that I know of. A brave person could
try grinding a top-pull MTB der to fit a road big ring. Shimano
has made top-pull MTB ders that have capacity up to 48t, which
is about all you need on a cross bike. Either way, unlikely to
index perfectly with road STI levers. You can also get a clamp-on
pulley and use a bottom-pull derailleur.

Quoted message said:

And there it is, in Berto's text, though there's no picture:

"In 1996 . . . Sachs front derailleurs got Inverse Action, with the
cable pulling the cage onto the smaller chainwheels and a spring
pushing it onto the larger chainwheels. This good idea was first used
by SunTour in the 1970s."

--p.314, "The Dancing Chain," 2nd edition.

IIRC, the SunTour reverse action front derailleurs were
bottom pull. A short length of cable housing ran from a
housing stop on the downtube near the BB, bent upward,
and ran up to a stop on the front derailleur. The model
name was "Spirt" (not Spirit):
http://members.jcom.home.ne.jp/suntour/fd/spirt.html

Quoted message said:

I remember the Suntour ones were not as good as a normal action. You
needed more than a spring to get the chain from 36 to 52 sometimes.

I personally liked my suntour SL front derailleur a great deal. "Push
either shift lever forwards to go faster" is the most intuitive
shifting you can imagine. The SL was a high quality low-cost
derailleur with lightweight aluminum cages.

They were all bottom-pull derailleurs, however. Reverse Action !=
Bottom Pull, the two features are independent.

And, there were regular-action derailleurs whose springs wore out and
which wouldn't pull the chain down onto the small chainwheel, too.

- Don Gillies
San Diego, CA

sal bass said:

i'm using campagnolo bar cons instead of indexed shimano.

also...the clamp-on pulley did cross my mind...but just for a second.
i can't see clamping on something to a $3000 + custom frame. seems
wrong. and yes the fabricator will integrate one...but that really
isn't the point.

If Campy barcons are friction on the front, then you can use pretty
much any derailleur with the right capacity. But I still don't know
any top pull FDs that are rated above 48t. The Shimano XT
conventional (high clamp not low clamp) ones from a couple
years back would do 48t - I think the number was FD-M751.
The high clamp ones were rated to 48 while the low clamp ones
were only rated to 44t, IIRC. I have barcons and a top pull FD
(even though my frame has a pulley) but my big ring is only 46.

The pulleys do work. Given this is a custom frame, you could get
a pulley anyway, for flexibility if you change your mind later. Or
you could get bottom pull cable routing. The reason to get top pull
cable routing is to keep mud and gunk out of the cable. Most people
who need this don't also need road chainrings, since a 52 is awfully
big off-road. A 48/12 still gives you a pretty big top gear.

IMO, if you are going to race and/or ride off-road a lot, it is a good
idea not to make your frame dependent on a rare component, such
as an unusual derailleur. RIding off-road, especially in muck, uses
components up more quickly.

Ben

Donald Gillies said:

Quoted message said:

I remember the SunTour ones were not as good as a normal action.
You needed more than a spring to get the chain from 36 to 52
sometimes.

Quoted message said:

I personally liked my SunTour SL front derailleur a great deal.
"Push either shift lever forward to go faster" is the most
intuitive shifting you can imagine. The SL was a high quality
low-cost derailleur with lightweight aluminum cages.

Quoted message said:

They were all bottom-pull derailleurs, however. Reverse Action !=
Bottom Pull, the two features are independent.

Quoted message said:

And, there were regular-action derailleurs whose springs wore out and
which wouldn't pull the chain down onto the small chainwheel, too.

I don't believe it. Either the spring broke or it yielded the first
time it was shifted to either extreme. Spring steel does not soften
or wear. Of course if you heated the spring while it was in its most
stressed condition you might get it to change, but then you would
smell the burning lubricant. I suspect the hinge got full of dirt and
had high friction.

Jobst Brandt

Quoted message said:

Spring steel does not soften or wear.

What kind of foolish theoretical result is Jobs spouting now ?? I
guess that campy just put parts #98/A and #787 into catalogue #17
because nobody would ever need them. Stick to your equations, Jobst.

- Don Gillies
San Diego, CA

sal bass said:

was there ever a front derailleur made in a TOP PULL variant for ROAD
doubles?

Yep, Sram made one...about 4 years ago

Quoted message said:

i've seen cross bikes (like the Bontrager CX) that have a pulley
integrated into the backside of the seat tube down by the bottom
bracket shell, that redirects the cable back up to the fixing bolt on
road front derailleurs.

but i don't think i've ever seen a top pull front der. for road
doubles.

sal bass said:

i'm using campagnolo bar cons instead of indexed shimano.

also...the clamp-on pulley did cross my mind...but just for a second.
i can't see clamping on something to a $3000 + custom frame. seems
wrong. and yes the fabricator will integrate one...but that really
isn't the point.

An 'E' clamp and the pulley is hardly visible and it will make yer rig
'work'.

Quoted message said:

Quoted message said:

Quoted message said:

>On 4 Sep 2006 18:26:11 -0700, "sal bass" <[email hidden]> wrote:
>
>>was there ever a front derailleur made in a TOP PULL variant for ROAD
>>doubles?
>>
>>i've seen cross bikes (like the Bontrager CX) that have a pulley
>>integrated into the backside of the seat tube down by the bottom
>>bracket shell, that redirects the cable back up to the fixing bolt on
>>road front derailleurs.
>>
>>but i don't think i've ever seen a top pull front der. for road
>>doubles.

Not a contemporary one that I know of. A brave person could
try grinding a top-pull MTB der to fit a road big ring. Shimano
has made top-pull MTB ders that have capacity up to 48t, which
is about all you need on a cross bike. Either way, unlikely to
index perfectly with road STI levers. You can also get a clamp-on
pulley and use a bottom-pull derailleur.

Quoted message said:

And there it is, in Berto's text, though there's no picture:

"In 1996 . . . Sachs front derailleurs got Inverse Action, with the
cable pulling the cage onto the smaller chainwheels and a spring
pushing it onto the larger chainwheels. This good idea was first used
by SunTour in the 1970s."

--p.314, "The Dancing Chain," 2nd edition.

IIRC, the SunTour reverse action front derailleurs were
bottom pull. A short length of cable housing ran from a
housing stop on the downtube near the BB, bent upward,
and ran up to a stop on the front derailleur. The model
name was "Spirt" (not Spirit):
http://members.jcom.home.ne.jp/suntour/fd/spirt.html

this won't get used off road....although it MIGHT see a few unpaved
roads.

but i'm not looking to top routing to keep the mud out...but i've
always admired the look of the cross bikes that have all the cables
routed with the top tube. looks much better than downtube cable
routing.

this bike will see more urban streets so you're right about the
chainrings....BUT....it would be nice to have the option to use a
single or double. it's only going to have 4 cogs mounted on a specific
hub.

no racing.....at all....ever.

but you're right about finding parts that can easily be found. that's
something i need to keep in mind.

this bike isn't really going to be a road bike in the general sense.
most road bikes these days are far too limited for general use. i
think what rivendell offers makes more sense than the usual cookie
cutter frames found these days in bike shops.

i just need something more practical.

Quoted message said:

sal bass said:

i'm using campagnolo bar cons instead of indexed shimano.

also...the clamp-on pulley did cross my mind...but just for a second.
i can't see clamping on something to a $3000 + custom frame. seems
wrong. and yes the fabricator will integrate one...but that really
isn't the point.

If Campy barcons are friction on the front, then you can use pretty
much any derailleur with the right capacity. But I still don't know
any top pull FDs that are rated above 48t. The Shimano XT
conventional (high clamp not low clamp) ones from a couple
years back would do 48t - I think the number was FD-M751.
The high clamp ones were rated to 48 while the low clamp ones
were only rated to 44t, IIRC. I have barcons and a top pull FD
(even though my frame has a pulley) but my big ring is only 46.

The pulleys do work. Given this is a custom frame, you could get
a pulley anyway, for flexibility if you change your mind later. Or
you could get bottom pull cable routing. The reason to get top pull
cable routing is to keep mud and gunk out of the cable. Most people
who need this don't also need road chainrings, since a 52 is awfully
big off-road. A 48/12 still gives you a pretty big top gear.

IMO, if you are going to race and/or ride off-road a lot, it is a good
idea not to make your frame dependent on a rare component, such
as an unusual derailleur. RIding off-road, especially in muck, uses
components up more quickly.

Ben