Bicycle Mechanics - sloppy derraileurs

i have a bike i haven't ridden since my concussion last year. i've always had something wrong with my shifting. before when i did ride my bike everyday, i began to notice that i couldn't use certaiin gears and that it was hard to engage all but the middle front chainrings. i didn't really mind at first, but now that i'm trying to ride again it seems my bike has gotten worse. the chain skips around from gear to gear on the cassette so i can't really pedal good. in the front i could only adjust the front derraileur so that i can engage to either just the middle and small chainring or the big and middle chainring. i tried adjusting the rear derraileur too, but the fourth to second chainring always have problems. the chain won't stay on those gears, it always has to jump to the next larger or smaller gear then back to whichever one it's suppose to, then do it again. i'm going to but grease so that i can install new cable line, but untill i get to, i was wondering if there could be anything else wrong. thanks for any help.

You might want to hold that thought of new cables. First...Cables have a certain amount of "stretch" in them...I recommend shifting to a gear withough the wheels spinning.....just in you garage or something. Leave this over night and see if you can go to an even harder gear...with the bike still. Be carefull...but this might help in stretching the cable. ALL cables stretch a bit, but anyone correct me if im wrong. Also...the adjustments on your derailleurs are most likely just end-point adjustments. They restrict how far the chain will go on the biggest or smallest cog. There is also a barrel adjuster to shorten/lengthen the cable to have the right adjustment. If you cant figure something out then...keep trying to see if you might be able to adjust it from the handle-bars. If all else fails...try to re-posistion the cable at the derailleur in/out to what you need. IF anyone sees anything wrong with this pleas e correct me.... :)

I think the most likely cause is the mechanism being gummed up with a mixture of oil, rust and dirt. Thorough cleaning of chain, sprockets, chainrings, deraillers and cables with something like WD-40 or kerosene. Then chainlube like white lightning, a small amount of light oil on the deraillers and cables.

You chain and sprockets may need replacing, but I dont think they would be the cause for jumping between gears, only of skipping in one gear.

I think the most likely cause is the mechanism being gummed up with a mixture of oil, rust and dirt. Thorough cleaning of chain, sprockets, chainrings, deraillers and cables with something like WD-40 or kerosene. Then chainlube like white lightning, a small amount of light oil on the deraillers and cables.

You chain and sprockets may need replacing, but I dont think they would be the cause for jumping between gears, only of skipping in one gear.
I think his deraliers need proper adjustment. www.parktool.com has the complete ho to.

You might want to hold that thought of new cables. First...Cables have a certain amount of "stretch" in them...I recommend shifting to a gear withough the wheels spinning.....just in you garage or something. Leave this over night and see if you can go to an even harder gear...with the bike still. Be carefull...but this might help in stretching the cable. ALL cables stretch a bit, but anyone correct me if im wrong. Also...the adjustments on your derailleurs are most likely just end-point adjustments. They restrict how far the chain will go on the biggest or smallest cog. There is also a barrel adjuster to shorten/lengthen the cable to have the right adjustment. If you cant figure something out then...keep trying to see if you might be able to adjust it from the handle-bars. If all else fails...try to re-posistion the cable at the derailleur in/out to what you need. IF anyone sees anything wrong with this pleas e correct me.... :) Yeah, most of it is off base. Your idea of cable stretching is bogus. www.paktool.com has the complete how to on derailer adjustment.start at the beginning,not somewhere in the middle.

i have a bike i haven't ridden since my concussion last year. i've always had something wrong with my shifting. before when i did ride my bike everyday, i began to notice that i couldn't use certaiin gears and that it was hard to engage all but the middle front chainrings. i didn't really mind at first, but now that i'm trying to ride again it seems my bike has gotten worse. the chain skips around from gear to gear on the cassette so i can't really pedal good. in the front i could only adjust the front derraileur so that i can engage to either just the middle and small chainring or the big and middle chainring. i tried adjusting the rear derraileur too, but the fourth to second chainring always have problems. the chain won't stay on those gears, it always has to jump to the next larger or smaller gear then back to whichever one it's suppose to, then do it again. i'm going to but grease so that i can install new cable line, but untill i get to, i was wondering if there could be anything else wrong. thanks for any help.Besides probable faulty derailer adjustment both front and rear, jumping cogs in the rear can be lots of things. If derailer adjustment doesn't cure it it could be cable or casing, worn chain or cogs or both or bent derailer hanger. Take a look at the repair section at www.parktool.com. If you don't have a clue, take it to a good LBS rather than screw it up worse.

but is it true that cables do stretch?....ive heard from many people about this happening?....