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Old 07-19-10, 12:30 PM   #1
pierce
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front dérailleur conundrum

so, I built up a custom hybrid using a funky taiwan steel frame, and 700c wheels, using a 7 speed wide range freewheel in back (Acera dérailleur) and a FSA compact road 50/34 double ring in front (a used shimano 105 I scrounged). Since I'm using friction shifters (vintage Suntour thumb shifters rock!), all was good, especially after I added 2mm spacers to the small ring so the chain wasn't hitting the big ring when crossed...



I decided that frame was too small, and scored a late 90s Specialized Crossroads in "M"(18) which is just about perfect... swapped all my parts onto it...




catch-22, its rigged for a top pull front. For now, I'm using the crappy tin-can AceraX front triple derailleur with my double ring and its actually shifting OK but its kinda funky having that long cage hanging down...

so... questions... are there any double front dérailleurs that are top pull? Do I have any other cheap options other than brazing cable mounts on the down tube (right now, all three cables are routed under the top tube, which is quite neat.

or, should I just go ahead and stick with a triple and maybe a nicer top pull triple front? I'll have to find a better crankset than the one that came on this frame, its one of those stamped steel riveted pieces of c#@& and weighs multiple pounds..

Last edited by pierce; 07-20-10 at 12:03 AM. Reason: updated picture of new frame showing compact double crankset
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Old 07-19-10, 12:48 PM   #2
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If you are not using indexed shifting anyway ... I don't think it matters wether your front derailleur is dual or triple ... as long as you set it up right and get the hi & low screws dialed in right it should be fine.
I'd say: use the acera untill it breaks and see how long it lasts ... then you can still consider moving up in quality.
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Old 07-20-10, 12:02 AM   #3
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If you are not using indexed shifting anyway ... I don't think it matters wether your front derailleur is dual or triple ... as long as you set it up right and get the hi & low screws dialed in right it should be fine.
I'd say: use the acera untill it breaks and see how long it lasts ... then you can still consider moving up in quality.
well, the triple front has a much longer cage than a double, also its curvature is more suited to a smaller big chain ring than the 50T I have, so I had to put it pretty far up from the big ring so the back/bottom wouldn't scrape teeth. but I've been searching catalogs online and come to the conclusion that all road double derailleurs are bottom pull, so I guess I'm SOL.
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Old 07-20-10, 06:05 AM   #4
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The derailleurs cage will indeed not fit perfectly since the difference in teeth is bigger and I havent heard of an actual double 50-34 top pull derailleur before.
If you can't get it to work properly and absolutely need a double 50-34 specific derailleur, there allways is the option to use some sort of reversing cable routing wheel to use a bottom pull derailleur on a top pull frame or you could simply attach new cablerouters to your frame and make it bottom pull
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Old 07-20-10, 06:09 AM   #5
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I found a perfect derailleur for you: Suntour FD8-NRX ... it is 50-34 and has dual cable routing
The trick will lie in finding someone that sells it seperately though but good luck!
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Old 07-24-10, 12:26 AM   #6
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always a catch-22, i'm not sure that FD8-NRX has a 28.6mm clamp. the link to the service manual doesn't even mention this specific FD but all the others are 31.8/34.9 (fat tube alloy).
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Old 07-24-10, 01:46 AM   #7
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You're lucky your frame is thinner than the derailleur, because getting a 31.8mm derailleur to fit on a 28.6mm frame can be done by using some bended metal pieces to fit inbetween.
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