chain problem. front and rear gears. help!
 

the past few rides my chain has been doing some bad things. i have a shimano 105 double with a 9 gear hub (did i say that right?). when im shifting from the low to high gear in the front the chain just pops right off towards the crank. then in the back, the 3 or 4 gears closer to the wheel are going CRAZY! when trying to downshift the chain cant make up its mind where to go. it hops from 1 gear to the other then back and forth. doesnt sit on one of the gears just keeps switching.

ummm, help me?

Have you been fooling with the little screws on the front derailleur? Sounds like the front problem is due to the high limit screw being adjusted out too far.

The rear "hunting" is normally cable-tension; too loose or too tight will cause such problems, as will too much gorpy lube built up.

Try this: Clean up the chain, cogs, etc., and re-lube with a small amount of quality lube. Run the rear DR down to the smallest cog, and see how much play is in the rear DR cable. There should be little or none.

thats one of the two small screws on the front derailer right?

an easy way to get really good cable tension in the rear derailluer: shift it to smallest cog, release the set screw that clamps the cable, so there is no tension. dial the cable's barrel adjustor out about half way. pull on the derailluer cable just so its snug, then retighten the pinch bolt. shift it through its gears. if its hesitating going up into easier gears, turn the derailluers barrel adjuster to the left, and the opposite if its hesitating going down.

Is there a similarly easy way (or any way) to regain good tension on the front derailer? It hurts my thumb to push my rapid-fire shifter over to upshift (get to bigger chainrings). It's not callousing, it's like bruise is just getting bigger and deeper.

For derailleur adjustments go to the Park Tool website. Find the instructions for adjusting derailleurs. Start at the beginning, do all of the steps in order. Don't leave anything out.
http://www.parktool.com/repair/byreg...ageField2.y=10

Al