Bicycle Mechanics - adjustment of front deraileur

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Melt
08-31-03, 10:08 AM
right now when i am on the first chainring (lowest) and then on the higest on the rear cassette the chain rubs the front deraileur on the side closest to the frame. There are two adjustment screws, high and low ... which ones do i adjust to get this **** runnin right?

Davet
08-31-03, 11:44 AM
Melt: The Park Tool web-site has a very detailed set of instructions on how to set up your derailluer: http://www.parktool.com/repair_help/howfix_frontderailleur.shtml

Follow the directions, from start to finish and in order. Each adjustemt affects another, so it's necessary to do the complete thing.
joeprim
08-31-03, 02:57 PM
Melt

It might be that you can't adjust this out. It may be that you shouldn't cross the chain that much. The Shimano website says it's doable but not advised to cross the chain too much.

Joe

Davet
08-31-03, 03:04 PM
Melt: If you are cross-chaining.....don't! If you run your gearing in the big/big or small/small combos, you will get chain-rub on the dérailleur, and more importantly you will accelerate the wear on the chain, chainrings and rear cogs.
John E
08-31-03, 03:05 PM
The sole purpose of the low-gear adjusting screw is to set the cage to barely clear the chain in the small front - large rear (lowest-ratio) combination. Likewise, the sole purpose of the high-gear adjusting screw is to set the cage to barely clear the chain in the large front - small rear combination. Particuarly with a modern 9x3 or 9x2, you have no business riding in either cross-chain (large-large or small-small) combination, although the small-small cross combination is ideal for bicycle storage, because it relieves tension on all three (or four) transmission springs.
Bokkie
09-04-03, 01:10 AM
Your front der might also be running at a slight angle across the chain line so shifting it slightly might help. View it from above and you'll see if it's touching. Height is useful. I think the bottom of the der needs to be about 1mm above the highest tooth with chain on it or something like that.

Six things (at least) usually influence smooth running: der height, der angle, hi screw, lo screw, cable tension, cable condition. Adjusting the front der is not too bad to achieve. Problems occur if you make too many changes at the same time and then are left guessing as to which change made it better, or worse!:)