Fixing/tweaking front derailleur?

faaj

Hi, its been a few montns since i got on my road bike, i remember before the chain etc. was perfect no scraping or skipping etc. However when i got on the bike after a few months the chain now scraps the front derailleur housing. e.g. if im on the second cog (out of 3) on most gears the chain scraps the housing. Also i cant get the chain on the third cog. I guess this is because my derailleur need some tweaking and i understand that this usually happens if the gear wire slowly loosens over time.
I tried to fix the front derailleur today except i found it pretty difficult as i find that 2 hand aren't enough . What im trying to do is using allen key and plier is to pull more of that gear cable out onto the front derailleur so i get more tension while chaing the gears. Is this right and are there any tip on how to do it?
I noticed there are two small screws on the derailleur, i know about the rear derailleur small H and L screws etc. Do these ones on tbe front do anything?

Thanks, and btw i dont have a work stand so i guess putting the bike upside down or leaning on the wall would work.

Gerry Attrick

OK Faaj........have a look here:
http://bicycletutor.com/adjust-front-derailer/

hammerite

faaj wrote:

Hi, its been a few montns since i got on my road bike, i remember before the chain etc. was perfect no scraping or skipping etc. However when i got on the bike after a few months the chain now scraps the front derailleur housing. e.g. if im on the second cog (out of 3) on most gears the chain scraps the housing. Also i cant get the chain on the third cog. I guess this is because my derailleur need some tweaking and i understand that this usually happens if the gear wire slowly loosens over time.
I tried to fix the front derailleur today except i found it pretty difficult as i find that 2 hand aren't enough . What im trying to do is using allen key and plier is to pull more of that gear cable out onto the front derailleur so i get more tension while chaing the gears. Is this right and are there any tip on how to do it?
I noticed there are two small screws on the derailleur, i know about the rear derailleur small H and L screws etc. Do these ones on tbe front do anything?

Thanks, and btw i dont have a work stand so i guess putting the bike upside down or leaning on the wall would work.

the to screws on the front der are L and H. You need to research which is which as it's not usually marked on road bikes.

If you can't get the chain onto the big ring I'm guessing that your chain is rubbing on the outside of the cage. Change gear so that the chain is on the bottom ring on the front and the top ring on the back (the chain will be straight). Firstly make sure the cage is staight, if it isn't loosen the clamp and twist slightly to make it straight.

Check to see how far the cage is from the chain on the inside. It should be about 2mm away from the cage. If it's over 2mm away then turn the L screw, you chould see the cage moving across closer to the chain, adjust it until it is about 2mm away.

You should then be able to put the chain into the top ring. Now on the top ring just make sure that the cage is at the right height and the cage doesn't move too far across. If it is too far then adjust with the H screw o it is only 2mm away.

billybiker

Make sure cable is slack in small ring!

Meds1962

Use the link Gerry Attric provided, those instructions are as straightforward as you will find anywhere. Follow them carefully and methodically and you will be ok eg. don't forget that when you set the mech for the inner chainring that the chain must be on the largest sprocket and vice versa when you set it for the outer chainring.

Try to get the gap between the mech plate and chain as tight as you can without actually touching as this will minimise the chance of chain rub at the other extreme ie. when in large / large or small / small gear combinations.

McBain_v1

If Sheldon Brown's website is still up I'd go there - excellent articles on gear tuning.