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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 |
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#2
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Derailleur for older frames
"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 .... |
#3
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Derailleur for older frames
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. |
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Derailleur for older frames
"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 |
#5
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Derailleur for older frames
"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 .... |
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Derailleur for older frames
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. |
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Derailleur for older frames
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. |
#8
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Derailleur for older frames
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). |
#9
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Derailleur for older frames
"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 .... |
#10
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Derailleur for older frames
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. |
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