Bicycle Mechanics - Front Derailleur Cage Rubbing Chain

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TrekRider
05-22-04, 01:12 PM
When I am on any of the three smallest cogs and the big chain ring, the inside of the derailleur cage rubs the outside of the chain. It is not bad, but enough to distract me.

Can this be a simple adjustment with the limiting screws or will it require loosening the cable and re-setting everything?

slvoid
05-22-04, 02:49 PM
Every bike I've been on has a slight rub at the highest gears. Adjust your H limiting screw on the front so that it backs off a little. Either that or make sure the derailler's not bent.
Midget
05-22-04, 03:27 PM
Check that your top chain ring is not bent. Mine likes to bend on me (careless riding and no bash guard helps it bend). also if you have newer shiffter than you might be able to somply just wind the screw where the cable goes into the shiffter normally no more than a 1/4 turn should do just play as you ride.

Have fun

Grampy™
05-22-04, 06:16 PM
Every bike I've been on has a slight rub at the highest gears. Adjust your H limiting screw on the front so that it backs off a little. Either that or make sure the derailler's not bent.

It should not rub if it is adjusted right..... check your set up or take it to your LBS. It's a fairly simple adjustment.... :)
Retro Grouch
05-22-04, 07:47 PM
When I am on any of the three smallest cogs and the big chain ring, the inside of the derailleur cage rubs the outside of the chain. It is not bad, but enough to distract me.

Can this be a simple adjustment with the limiting screws or will it require loosening the cable and re-setting everything?

If the chain is rubbing on the derailleur cage, then the front derailleur needs to be adjusted. Resist the urge to just fiddle with the limit screw or cable tension until you are sure that everything else is right. That kind of random fiddling on the front derailleur is the road to ruin. I'm a strong advocate of loosening the cable and starting from scratch.
Rev.Chuck
05-22-04, 07:58 PM
Also, if you look at the rear of the der, you will see two pivots. These are allen head bolts and they often will loosen and cause havoc with adjustment. Make sure they are tight before doing any adjustment. Most times, if the front der. suddenly goes out of adjustment, this is the reason. Don't take them all the way out, they can be hard to get in under spring tension. If you have suddenly had the der. go out and it is not these pivots, check the cable at its end in the shifter. If the problem is because the cable is failing, now is the time to replace it, not after it breaks and the end gets stuck in the shifter :(