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Old 02-19-06, 08:26 AM   #1
Desperado
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Front Derailluer recomendation needed

I switched BB's and cranksets to get lower gearing for touring, put on a Sugino triple 48 tooth large ring(48/36/26), the front derailluer that was on the bike is an old SunTour VX, I put this on with the new crankset and the VX does not have enough outward travel to lift the chain onto the large ring, even with the limit screws backed all the way off, so I'm looking for a derailluer with more range of motion, I am using friction bar end shifters and the front cable is routed from the downtube then up from the bottom bracket to the derailluer, so some types probably wouldn't work, they look like they need the cable comming down the seatpost, any way does anyone have an idea what I could use, that has a little more outward range of motion, Thanks for any help
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Old 02-19-06, 09:45 AM   #2
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You have a very normal "bottom pull" cable arrangement. The "top pull" cabling you describe is typically used on MTB and Cyclocross bikes to get the cables away from dirt and impact damage but is almost never seen on road bikes.

Try any of the current Shimano road triple front derailleurs which should solve your problem unless your new bottom bracket is much too long. Does the granny ring clear the chainstay with a big gap? If so, a shorter bb may solve your problem too.
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Old 02-19-06, 10:27 AM   #3
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It doesn't look like the gap is too big, about 3/8'', and it looks as if I used a shorter spindle, the backside of the crankset were it slides on to the taper would bottom against the bottom bracket shell, there is only about 1/8'' of space there now, OK thanks for the help, maybe the old VX just doesn't have the throw that I need, will go to the LBS and look for a modern FR, I'LL take the old one and do some comparing , Thanks Again
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Old 02-19-06, 10:37 AM   #4
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Quote:
Originally Posted by Desperado
It doesn't look like the gap is too big, about 3/8'', and it looks as if I used a shorter spindle, the backside of the crankset were it slides on to the taper would bottom against the bottom bracket shell, there is only about 1/8'' of space there now, OK thanks for the help, maybe the old VX just doesn't have the throw that I need, will go to the LBS and look for a modern FR, I'LL take the old one and do some comparing , Thanks Again
Might be wise to check your chainline first before buying a new FD. It's amazing how much difference there can be in BB length after changing the chainset. The last time I change a triple Suntour c/s for another triple Suntour c/s and went from a 122 ml to a 113 ml BB.
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Old 02-19-06, 11:03 AM   #5
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It's true that various cranksets are designed to work with different bottom bracket spindle lengths, to get proper chainline.
However, the OP said that he'd changed his bottom bracket when he changed his crank, and he also said that he can't make chainline any narrower, as he's only got 1/8" between the inner edge of the crank, and the BB shell.
Sounds like the need is just for an FD with more throw. Mountain deraillers from the early/mid-90's, designed to work with 46/36/26 rings, will work well too. As long as they're standard bottom-pull design.
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Old 02-19-06, 03:26 PM   #6
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FWIW, I'm running a Tiagra FD with Tiagra Brifters on my C-dale with a 44x32x22 mtb crank and had absolutly NO problems setting it up. This is with tiagra brifters Got it set about 1 pennys thickness above the big ring, and set the limit screws as normal. It doesn't shift as quick as a dura-ace on a double ring, but more than sufficent for a touring bike in my case.

I may do some fine tuning with making the cage a bit wider in the rear to make it less sensitive to chain line in some gears, but if you're running friction that's a moot point.

Steve W.
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Old 02-19-06, 03:57 PM   #7
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Originally Posted by Mentor58
Got it set about 1 pennys thickness above the big ring, and set the limit screws as normal. It doesn't shift as quick as a dura-ace on a double ring, but more than sufficent for a touring bike in my case.
That's a good point. How close is your front derailleur cage to the big ring and did you lower the front derailleur when you switched to the new crank? If the gap is too large, it will take more travel to get the shift to the big ring to occur and that could be the problem.
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