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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 06-27-09, 10:13 PM   #1
scifikid
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Front Derailer problem on Burley

We purchased a Burley Tandem about 5 years ago. I've never been comfortable with grip shifters so we changed to thumb shifters. It seemed to work ok for a while but this season we've been having a lot of trouble shiffting and with the chain falling off.

We're being told that thumb shifters aren't compatible with the bike. The shop changed the front derailer and chain, and it's working somewhat better. However, we can't drop to the small ring in the front when going flat or uphill. It will only drop when going downhill which isn't very useful.

I can only hope I not the only one out there that doesn't like grip shifters and there is a solution out there. Thanks.
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Old 06-28-09, 12:12 AM   #2
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I've got some XT rapid fire shifters on our Burley. We have no problem shifting to the granny gear. I'm using a jump stop deflector to keep the chain on the small ring. With the stop, I've got the front travel limit adjusted farther without being worried about dropping the chain to the inside.

http://www.jensonusa.com/store/produ...Deflector.aspx
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Old 06-28-09, 06:14 AM   #3
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Quote:
Originally Posted by scifikid View Post
I can only hope I not the only one out there that doesn't like grip shifters and there is a solution out there.
Have you always had a little trouble getting the chain to drop into the smallest chain ring (i.e., granny or alpine)?

If so, and if you haven't done so already, you may be able to address the problem through technique vs. a hardware change. When making the shift to granny you'll want to ask your stoker to soft pedal while you do the same so that the drive train is momentarily unloaded... pretty much the same condition it's in when it will shift on a downhill.

When it comes to hills, you'll also want to make the shift to your smallest chain ring early on before your cadence begins to fall below 70 or so and while you still have some momentum so the momentary soft pedal stoke doesn't cause you to stall and/or the chain to overshift the small chain ring.
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Old 06-28-09, 06:19 AM   #4
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Couple of ideas:

1. I second the idea of using a "Jump Stop" or "3rd Eye" to prevent overshifting.
2. Sometimes a subtle change in the angle of the derailleur on the seatpost makes a big difference.
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Old 06-28-09, 09:48 AM   #5
scifikid
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Thanks for all of the suggestions. We have tried "soft-pedaling" but it still won't drop into the granny gear unless we're going down hill. I'm going to look into the jump stop. We didn't have a problem shifting until this year.
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Old 06-28-09, 11:46 AM   #6
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Agree will the above comments. Another thing to try is to pre-shift into position 9 or 10 (the biggest cassette gears) prior to dropping into the Granny Gear, and prior to shifting into your Granny Gear the low gear. If you are in position 4-6, it might be just enough of a strain that you won't get a smooth shift.

Another one to check is to make sure you are not getting any cable binding under your bottom bracket. This is an area that a lot of people forget about and it can get really dirty. It can cause your derailleur to have a lot of sticky shifting problems. I generally sleeve the cable in a short plastic tube, such as the plastic tube that is on the inside of a brake cable, when I put on a new cable.
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Old 06-28-09, 11:57 AM   #7
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I've got Campy brifters on my daVinci with a quad chainring:30-24-18-12. I was having difficultly going from the 24 to the 18, would drop into the 12 and, conversely, go directly from the 12 to the 24. My LBS got it dialed in, but I can tell you it took some very subtle adjustments to get it just right one of which was a very small rotation of the FD (1 degree maybe) to kick the tail of the derailleur outboard. I still need to hve a decent cadence to get a good 18-12 shift, but the LBS cautioned that if I want to try a small tweak to the cable tension only make a 1/16 turn adjustment. There is a sweet spot, but may take a bit to find it.
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Old 06-28-09, 04:34 PM   #8
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A little tweaking of the rear part of the front derailleur cage itself can also help.
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Old 07-01-09, 04:10 PM   #9
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We're new to the tandem scene. We started with a set of SRAM twist shifters running 8 speeds on our Burley, and four months later we have drop bars and Ultegra brifters on a 9 speed cassette. Other folks have pointed out a few things for us which have been helpful.

My $0.02 worth

1) Tandem cables are longer than single bikes, so they stretch a bit more and it takes a little more time to shift.

2) As pointed out, anticipate and downshift early, or stuff like this can happen to you. Notice the bent big gear, one missing spoke, a kevlar replacement, and no cable to the rear D/R. Two people can generate enough power to bend a gear and really screw things up if something locks. We rode the last 11 miles of a charity ride using just the two smallest chain rings. It was a real learning experience. This was, I think, caused by trying to shift down in front and up in back just as we began to climb a hill, on a corner, at a real low speed.


3) Shift up in back before you shift down in front.

4) What type of front D/R is on your tandem? The SRAM front shifter on my Burley was a micro-index type, very akin to a bar end shifter, so it was very easy to put the D/R wherever it needed to be. If you have a "road" front D/R (Tiagra-105-Ultegra) it may not shift correctly with "mountain" thumb shifters due to the amount of cable pull.
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Last edited by Monoborracho; 07-01-09 at 04:13 PM.
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