One of many things that i hate is bad shifting gears, i hate when it cant shift in one gear, ghost shifting, slow shifting, squeaking,etc.
All of this problems are caused because of bad tuned rear derailleur.
Here, in Serbia, bike shops usualy charge you 500 rsd ( about 5,6 $ ), but problem isnt money ( well, 10 $ is average daily wage in Serbia , so you could say its overprized, but...) problem is that even you want to give them money, they arent fixing that problem for eternity, its only fixed for 1000km . ( belive me, i bought new bike 3 months ago, they did zero service , and next month ( in june) they did first service , tuning brakes, gears,..., when they finished that service i bought speedometer( measuring speed, distance, ...) and since then i rode about 700km ( maybe 900 because my dad reset it 2 times) . After only 700 km cables are again losen, and my gears not working properly....................................
so we are runing into other problem, after only one month i need to go again to bike shop and they will charge me 5 $ ( first two service (zero and first one) are free) ( 5$ for me, but in usa,uk,australia, many other states bike shops are charging 20 $ maybe less maybe more) , and they will fix it, but then after 1000 km they i will, need to go again, and then again, and again,again....
also expenses are raising with every other visit, because after 3 or 4 tune ups, they will say that you need new cable (thats also 5-20 $))
so do you know where i am going, after every bike shop visit, they will say that you need some new part (it will actualy need you) but you will know how to change it alone. ( you all know that chain shoud be changed every 3000 km, casette every 6000km??????)
so enough of this theorys.
tuning up your derailleur is realy simple and fast ( i was stuned when i finished iit in under 2 minutes)
Step 1: Prepare Gears
when you put it onto the stand, shift gears on casette or freewheel to smallest one .
Step 2: Adjusting Derailleur
first you will turn cable barrel adjuster clockwise (you need to turn that into the derailleur) , that will loosen cable tension .
after that take wrench or allen key and unscrew (loosen)cable anchor bolt.
when you done with looosening anchor, just take cable and pull it ( you need to tighten cable/cord)
after that you just need to tighten back anchor bolt and you are done with tightening cable/cord
Step 3: Tuning
but there is 99% that this part will be easy
you will see about what i am talking.
first you will see 2 screws near each other, thats limit screws
they are marked h and l
because you are at bootom cog you will use bottom screw (i thing l one ,i am not sure, just use bottom one)
this screw as name tells limit your derailleur, actualy its limiting cage of derailleur which causing that everytime when you shift into the smallest cog your chain will not slip
you need to turn that screw until your jockey wheel is under and parallel with smalest cog .
next you will shift through gears (avoid first 2 gears ) and if its not shifting smoothly you need to place gears at middle ones (4th ,5th gear) and turn cablle barrel adjuster ANTI CLOCKWISE until it is in line (parellel) with that cog
try few more times, and play with that barrel adjuster because he is important for shifting through gears, and shifting smoothly
when you finished with smallest cog, go to first gear, and adjust upper limit screw until the jockey wheel and that cog is in line
and last thing, is to adjust B screw if your derailleur is rubbing onto the biggest cog
big note, it really helps if you clean and lubricate chain and derailleur because it will help your adjusting ( lubricated chain shift better then dry,rusty,dirty chain)