Derailleur for older frames

Dear All,
Replacing a front derailleur I discover that the no longer sell ones the fit
older bikes that have a seat tube that is 74o . Any suggestions about where
I could a suitable derailleur or any suggestions of a work around.
Thanks,
Neil

"Neil" wrote in message
...
Dear All,
Replacing a front derailleur I discover that the no longer sell ones
the fit older bikes that have a seat tube that is 74o . Any
suggestions about where I could a suitable derailleur or any
suggestions of a work around.
Thanks,
Neil

eBay is a good source for obsolete components.

Some are slightly used or you may strike lucky and find
something suitable which is NOS (new old stock) at a
reasonable price. If its also NIB (new in box) or is
a rare model the price may be considerably higher.

You need to go into "Bike Parts" then try retro or vintage
front changers front mechs etc.

michael adams

....

On Nov 30, 6:24*pm, "Neil" wrote:
Dear All,
Replacing a front derailleur I discover that the no longer sell ones the fit
older bikes that have a seat tube that is 74o . Any suggestions about where
I could a suitable derailleur or any suggestions of a work around.
Thanks,
Neil

the precise frame angle doesn't matter. Do you mean you want a
derailleur for a steel frame. 28.Xmm clamp? Yeah, it's a bind.
Best to look for SH or old stock but adapters are also sold to fill
the gap between a regular steel tube and over-sized clamps.

"Neil" wrote:
Dear All,
Replacing a front derailleur I discover that the no longer sell ones the
fit older bikes that have a seat tube that is 74o . Any suggestions about
where I could a suitable derailleur or any suggestions of a work around.

I don't think there is any particular problem with a 74 degree seat tube,
that's what my tourer has and I've used an old campag and a new shimano
changer on it with no problem.

What's the tube diameter? Why won't newer ones fit your bike?

Tim

"Tim+" wrote in message
...
"Neil" wrote:
Dear All,
Replacing a front derailleur I discover that the no longer sell
ones the
fit older bikes that have a seat tube that is 74o . Any suggestions
about
where I could a suitable derailleur or any suggestions of a work
around.

I don't think there is any particular problem with a 74 degree seat
tube,
that's what my tourer has and I've used an old campag and a new
shimano
changer on it with no problem.

What's the tube diameter? Why won't newer ones fit your bike?

Tim


Maybe by "newer ones" he means braze on's ?
Whereas his has a clamp. Its so long ago that I encountered
clamp-on front changers that I'm not even sure whether tube
diameter was ever that much of an issue to start with. With
conventional 531 built lightweights anyway. Maybe when
Columbus got in on the act things changed.

My lightweight frame from the early 1980's has a braze-on front
changer which I'm assuming by that time were fairly universal.
A previous lightweight frame from the mid 60's had a clamp, as
they all did. As up until some point in the interim it was thought
braze-ons
of any kind - cable gear levers bottle cages etc. weakened the tubes.
Once having assembled a bike I never really keep up with the latest
developments in bike design - I just buy whatever is available. And
so quite
possibly foe all I know cheaper bikes may still feature all round
brackets
and clips on grounds of cost

michael adams

....

On Dec 1, 9:49*am, "michael adams" wrote:
"Tim+" wrote in message

...









"Neil" wrote:
Dear All,
Replacing a front derailleur I discover that the no longer sell
ones the
fit older bikes that have a seat tube that is 74o . Any suggestions
about
where I could a suitable derailleur or any suggestions of a work
around.

I don't think there is any particular problem with a 74 degree seat
tube,
that's what my tourer has and I've used an old campag and a new
shimano
changer on it with no problem.

What's the tube diameter? *Why won't newer ones fit your bike?

Tim

Maybe *by "newer ones" he means braze on's ?
Whereas his has a clamp. Its so long ago that I encountered
clamp-on front changers that I'm not even sure whether tube
diameter was ever that much of an issue to start with. With
conventional 531 built lightweights anyway. Maybe when
Columbus got in on the act things changed.

My lightweight frame from the early 1980's has a braze-on front
changer which I'm assuming by that time were fairly universal.

No. My Raleigh Competition (1984 or5 IIRC) was certainly a clamp-on.
Even in the year or so following both Raleigh and Peugeot were using
clamp-on fittings. Shimano's "aero" mech may have been fitted with a
brazed fitting but the consensus was that the tube-clamp fitting was
lighter and more versatile than providing for a brazed mounting. Thin
753 seat-tubes probably always had tube-clamps..

A previous lightweight frame from the mid 60's had a clamp, as
they all did. As up until some point in the interim it was thought
braze-ons
of any kind - cable gear levers bottle cages etc. weakened the tubes.

Reynolds was releasing some very thin tubes even before the marketing
of 753 so it's likely that everyone saw no need for change as the
"best" machines from the top builders would feature tube-clamps.

Once having assembled a bike I never really keep up with the latest
developments *in bike design - I just buy whatever is available. And
so quite
possibly foe all I know cheaper bikes may still feature all round
brackets
and clips on grounds of cost


They are more versatile and of greatest importance to the manufacturer
take 5 seconds less to affix and align during production, as well as
not requiring the frame-tab in the frame's build.

Due to ill health I had to reduce my outer ring from 48 (orig 52) to
42t on a bike with braze-on derailleur. The stretch, despite
modification of the derailleur was too far. After about 4 hours of
riding I got the tab ground off and a tube-clamp derailleur swapped
in. I made a bit of a mistake in letting go of my Chorus derailleur
but I saw it as no good and thought I could get a clamp-on of similar
fanciness when I desired. When that desire came, the tube-clamp fancy
racing derailleurs were not being stocked locally. What I shoulda
done is got an adapter, only AFAIK no production item was available.
I'll probably end up in 20 years time paying a small fortune for a
flat plate Record derailleur. They being most artistically desirable.

On Fri, 30 Nov 2012 18:24:07 -0000
"Neil" wrote:

Dear All,
Replacing a front derailleur I discover that the no longer sell ones
the fit older bikes that have a seat tube that is 74o . Any
suggestions about where I could a suitable derailleur or any
suggestions of a work around.

The angle quoted with newer front mechs is that between the seat tube
and the chainstays, rather than seat tube and horizontal - small rings
and slack seat tubes can cause clearance problems. On a non-specialist
bike (i.e. not downhill, jump etc.) you shouldn't need to worry about
that, just the max chainring size and seat tube diameter. Some mechs
come with a larger clamp plus shims to fit smaller tubes, some you may
need to get additional separate shims.

On Sat, 1 Dec 2012 09:49:35 -0000
"michael adams" wrote:

Whereas his has a clamp. Its so long ago that I encountered
clamp-on front changers that I'm not even sure whether tube
diameter was ever that much of an issue to start with. With
conventional 531 built lightweights anyway. Maybe when
Columbus got in on the act things changed.

My lightweight frame from the early 1980's has a braze-on front
changer which I'm assuming by that time were fairly universal.

Only on Italian road frames really, the rest were still mostly
clamp/band-on. These days with funny materials and tube shapes you're
more likely to find "braze-on" (I wonder when we're going to come up
with a new term for that - there's not much brazing on a carbon frame).

"Rob Morley" wrote in message
news:20121201152629.362e90a0@hyperion...
On Sat, 1 Dec 2012 09:49:35 -0000
"michael adams" wrote:

Whereas his has a clamp. Its so long ago that I encountered
clamp-on front changers that I'm not even sure whether tube
diameter was ever that much of an issue to start with. With
conventional 531 built lightweights anyway. Maybe when
Columbus got in on the act things changed.

My lightweight frame from the early 1980's has a braze-on front
changer which I'm assuming by that time were fairly universal.

Only on Italian road frames really, the rest were still mostly
clamp/band-on.

Am I not correct in thinking that "band-ons" required a lug brazed
to the frame ?

Whereas clamp-ons consisted of two matching cast halves,
which were held together with two bolts ?


These days with funny materials and tube shapes you're
more likely to find "braze-on" (I wonder when we're going to come up
with a new term for that - there's not much brazing on a carbon
frame).


Some of the early lugged aluminium frames, Vitus, Alan, were
apparently glued together and some of them had "braze ons" for
front mechs. Which presumably would be more accurately known as
gluons.
I thought that Star Trek had got there first, but apparently they're
actually vector bosons.



michael adams

....

On Sat, 1 Dec 2012 16:10:16 -0000
"michael adams" wrote:

Am I not correct in thinking that "band-ons" required a lug brazed
to the frame ?

No, properly "band on" is like the fitting for road brake levers - a
chrome steel band and an alloy boss that it tightens into.

http://www.retrobike.co.uk/forum/fil...r_view_183.jpg

It's more often (mistakenly?) used in reference to clamp-on mechs.
There was a (Suntour?) arrangement that used either that or a threaded
boss (bottle cage type I think, but could have been 6mm) on the seat
tube as an alternative braze-on arrangement, but it wasn't really
adequately adjustable in that mode. ISTR someone else (Simplex?) did
something similar but incompatible.