stupid ass front derailleur!

[scottzg]

I know there's plenty of more serious bikers here than me, i could use some help.

so i just rebuilt my vintage road bike, and i can't seem to get the front derailleur tuned right. Whenever i take a hard stroke, the chainring rubs against the ouside of the derailleur. I've adjusted the stops so that this doesnt happen, but either i can't get into any gear but my lowest and highest, or the chain falls off. I guess the chainring is flexing or something, but im stumped as to get it to stop. Any suggestions?

oh, its all shimano 600 components circa 1984

[206er]

this is assuming your cables are fresh, lubed, and routed in a good smooth way.
tighten chainring bolts
tighten crank bolt
tighten bottom bracket
make sure derailleur is more or less parallel with the chain, and that when chain is in the little ring, the derailler just barely clears the inside cage.
once that is done, properly adjust the cable. low gear on derailler, low gear on shifter, pull cable tight, clamp down, cycle the cable a bunch of times pretty hard to see what it does and stretch it, retighten as needed.

[Redlined]

Make sure your crank bearings are good and your bolts are tight. Try putting the bike on its handlebars/seat, take the peddles in either hand and wiggle them to see if there is ANY movement. Try this at several differant positions. ANY perceptible movement means you need to tighten/replace the bolt/bearings.

[G-reg]

Are you using the same "vintage" chain?

[scottzg]

nah, chain and all the wear stuff has been replaced. Bike has ~300 miles on it.

I'm about 220lbs and pretty fit, it only rubs when i torque on it; crankin in high gear or standing up hills. Thiis is after futzing with the derailleur quite a while to find the closest setting.

argh. maybe ill take it in to a shop.

[scottzg]

make sure derailleur is more or less parallel with the chain, and that when chain is in the little ring, the derailler just barely clears the inside cage.

appearantly the derailleur was toed in A LOT. I moved it out about 10 degrees, covering the bike shoppe sticker with the derailleur mount, to get it shifting properly. Now it shifts beautifully.

I got up to 55 goin down a windy like 2 lane road through the redwoods too.