Bicycle Mechanics - messed up gear shifting

Hello. I am fairly clueless when it comes to bike fixing.. so bear with me :)

My bike started getting screwed up a while ago but I decided it wasn't that big of a problem so I didn't care to do anything about it. But now everytime I leave the bike in any gear, it will jump up to the next gear and somtimes jump back down. It makes all this cilcking noises like the chain is trying to jump. In order to make it normal, I have to hold the shifter between two gears... for example to ride in 5th gear i have to hold the shifter halfway in between 5th and 6th.. sort of like 5.5th gear. If I let go.. it won't properly stay in 5th. It will clickity clack then jump to 6th.. then click click click and sometimes jump back down to 5th. If I just shift to 6th.. it will clickity clack, choke, and jump to 7th...then back down.. etc.. you get the picture.

Basically I have to keep my fingers on the gear shifter all the time I'm riding.. VERY inconvenient. I hope this you guys understand what I'm saying here lol. hope it's easily fixed also. Thanks for any help!! :D :o

im guessing all this noise is coming from the rear? if you look at your rear deraileur there are 2 screwes an H screw and an L screw. I believe the H screw tells it how far down (highest gear, smallest cog) it can go and the L the tells it how far up (lowest gear, biggest cog). try tinkering around with these a bit. this isnt the best answer but im sure someone will give you better info

Your issue is cable tension. If you need to hold tension on the shifter to keep it in a gear then you need to tighten the cable adjuster. This is the knob the cable runs thru right at the rear der. Looking at it from behind the bike, turn the knob counter clockwise a quarter turn. Then test. If it still does not want to stay in gear give it another quarter turn. Start this process with it in the smallest cog(far right). It sounds like it is so loose you may want to give it a full 360 turn before you even start tuning. You want to do this until it shifts easily to the larger cogs(to the left) Now that you have it shifting left OK shift to the smaller cogs(right) and make sure it does not hesitate to much. If you get to much hesitation you need to turn the adjuster clockwise a quarter turn. If you cannot get it to shift OK take it to a shop, you may have a binding problem that requires a knowledgable eye to fix or replace.

The two screws on the der. only control the limit of the der(They are called limit screws). So you would only move them if you have a problem with it not shifting to the biggest or smallest cog.

hmm ok thanks guy. I will try and get some tools to try and tigten it.

Hi Kv2 I'm having similar problems but not for the same reason, I would do exactly as Rev Chuck says, but you might want to check out some more detailed info on adjustment to help you get it right.

Check out my Thread "SIS adjustment?" for some great links to Park Tools website.

Regards Evo

im guessing all this noise is coming from the rear? if you look at your rear deraileur there are 2 screwes an H screw and an L screw. I believe the H screw tells it how far down (highest gear, smallest cog) it can go and the L the tells it how far up (lowest gear, biggest cog). try tinkering around with these a bit. this isnt the best answer but im sure someone will give you better info

If the derailleur ever worked right you shouldn't mess with the limit screws because they don't change either over time or with use. Almost all derailleur adjustments are made with cable tension and almost all require counterclockwise adjustment because cables only stretch, they never shrink or get shorter.