Derailleurs
03-12-12 | 02:00 PM
#2
Senior Member
Joined: Feb 2004
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From: St Peters, Missouri
Bikes: Catrike 559 I own some others but they don't get ridden very much.
03-12-12 | 02:05 PM
#3
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Joined: Nov 2008
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From: niagara region
Bikes: 1987 bianchi campione d'italia, 1970's eatons glider, 1990's hybrid, 1992 trek antelope
03-12-12 | 03:23 PM
#5
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From: Munising, Michigan, USA
Bikes: Priority 600, Priority Continuum, Devinci Dexter
03-12-12 | 06:33 PM
#7
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Joined: Sep 2009
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From: Madison, Wis.
Sorry to give you a joke answer earlier. A rear derailleur has 4 adjustments: a upper limit screw, a lower limit screw, a cable tension barrel, and a screw that I forget the name of.
The best way to tune a derailleur starts with some slack in the cable. You turn the two limit screws until the derailleur moves from right under the small cog to right under the largest cog. The pulley wheels should be in a ruler sharp line with the cog. Then you adjust the cable tension so that the bike shifts up and down with equal ease. If it is having trouble shifting to the larger cog, unscrew the barrel so the cable has more tension. If it is slow to shift to the smaller cog, screw in the barrel so the cable has less tension. Quarter to half turns at a time once you're getting close.
Lastly, that screw that I can't name controls how tightly wound up around the cogs your rear derailleur is. If you screw it in, your derailleur will open up, and will be easier to get to the largest cogs, but its overall performance may fall off a bit. So you want it as tightly wound as possible.
For the front derailleur, you just want to bend the cage with a pliers until it works to your satisfaction.
The best way to tune a derailleur starts with some slack in the cable. You turn the two limit screws until the derailleur moves from right under the small cog to right under the largest cog. The pulley wheels should be in a ruler sharp line with the cog. Then you adjust the cable tension so that the bike shifts up and down with equal ease. If it is having trouble shifting to the larger cog, unscrew the barrel so the cable has more tension. If it is slow to shift to the smaller cog, screw in the barrel so the cable has less tension. Quarter to half turns at a time once you're getting close.
Lastly, that screw that I can't name controls how tightly wound up around the cogs your rear derailleur is. If you screw it in, your derailleur will open up, and will be easier to get to the largest cogs, but its overall performance may fall off a bit. So you want it as tightly wound as possible.
For the front derailleur, you just want to bend the cage with a pliers until it works to your satisfaction.
03-12-12 | 06:43 PM
#8
Constant tinkerer
Joined: May 2010
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From: Madison, WI
03-12-12 | 10:03 PM
#9
Insane Bicycle Mechanic
Joined: Mar 2008
Posts: 10,156
Likes: 1,122
From: other Vancouver
My favorite that's rarely published: before tightening the bolt on the cable, shift the chain by hand to the second cog. (Usually the second smallest, unless you have a Rapid-Rise derailleur.) Shift the shifter into its last gear and take out the slack in the cable. Tighten the clamp bolt. This will put a little preload on the cable when the chain shifts onto the last cog, and usually results in much less fiddling with the adjustment from there. At least it does for me.
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