Gear clunking noise.

jon prothero

Just came back from my LBS for the third time and still my problem has not been solved. When i am going up a hill on my smallest ring ...... a noise like i am being pulled up to the top of a fairground ride appears. It is fine on the middle and big ring. Also all the gears change perfectly. I am a novice when it comes to maintenance, so the whole bike came back like this and with a (brake not working i shall post about that later) after i paid a lot of money for a full service. One of the things that was done was the back cassette was changed and the chain......might this be effecting that small ring at the front my thoughts are that also might need replacing. As i say though I know very little. Your advice would be very helpful as i have come to the stage where i feel i might as well learn to do things myself!

cooldad

Apart from what sounds like a rubbish LBS, probably a worn chainring if you use it a lot.
Learn to DIY.

jon prothero

Yes this is what i am hoping it is and yes i will be learning. thanks

delcol

got to ask as you say you are a novice....

you say small ring uphill.. if you are using the small ring which cog on the cassette are you in.....

small ring and the top 4 gears(4 smallest cogs) on a 9 speed casstte are not supposed to be used due to the chainline........

jon prothero

Yes i am aware, i am a novice at repair i am ashamed to say...... although i have been riding a bike for years so do change correctly hense the chain line and gearing up hill are correct.

Thanks

Ouija

If your not trying to use the smaller rings on the rear cassette (which causes the chain to rub against the middle front ring) then the only other possibility is that it's your rear derailler not having enough tension. Typically when on the small ring on the front, the rear derailler upper jockey wheel can actually bump into the teeth of the the rear cassette, causing a 'ratcheting' or 'clunking' noise. This can indicate that you've got too many chain links on the chain or that the rear derailler tensioner screw isn't set correctly (a little screw that stop the derailler contracting too much and bumping against the underside of the cassette).

Here's a pic from another thread of what i mean....



.. that jockey wheel shouldn't be anywhere near that cassette. So adjust the tensioner (or B Screw as it's sometimes called).

jon prothero

That i shall try thank you very much for your long reply and picture i shall let you know how i get on!

The Rookie

Some front mechs run quite high and as you select higher (smaller diameter) gears at the back the chain can run over the lower part of the front mech, as chains running on surfaces are what you here at fairgrounds it will be exactly the noise you describe, the answer is to get onto the middle ring earlier.

Simon

Ouija

+1 to what he said.

I f you only get the grating sound when on the smallest front and two smallest rear (a combination you shouldn't use anyway) then it's probably what "The Beginner" said above (chain dragging over the lower part of the front mech). If your getting it in all rear gears then it's probably the rear jockey wheel getting too close to the teeth of your cassette.

Anonymous

Rubbing on the front mech would be my first suspicion, especially if it goes away if you use the small ring at the front but shift to the middle at the back. If the mech cage is touching the chain, quarter turn on the barrel adjuster for the front shifter and see if you get a gap between chain and cage. I always forget which way to turn, but just try one way or the other and see if it moves. Just a tiny gap is all you need. If it doesn't move even with a few turns then you might have to play with the limit screws, but don't touch these otherwise.

I find front mechs are a pain and stretching cables over time along with other things can easily shift the cage slightly so it rubs when it didn't before.

You might find if you adjust it to avoid rubbing on the small ring, it starts rubbing on the big ring instead when in the small cog at the back. With a 3x I rarely could avoid both extremes from rubbing. Going to 2x makes it better, and 1x eliminates the whole damn front mech entirely (and easier to clean, plus more exercise).

Ouija

deadkenny wrote:

Rubbing on the front mech would be my first suspicion, especially if it goes away if you use the small ring at the front but shift to the middle at the back. If the mech cage is touching the chain, quarter turn on the barrel adjuster for the front shifter and see if you get a gap between chain and cage. I always forget which way to turn, but just try one way or the other and see if it moves. Just a tiny gap is all you need. If it doesn't move even with a few turns then you might have to play with the limit screws, but don't touch these otherwise.

I find front mechs are a pain and stretching cables over time along with other things can easily shift the cage slightly so it rubs when it didn't before.

You might find if you adjust it to avoid rubbing on the small ring, it starts rubbing on the big ring instead when in the small cog at the back. With a 3x I rarely could avoid both extremes from rubbing. Going to 2x makes it better, and 1x eliminates the whole damn front mech entirely (and easier to clean, plus more exercise).

That too. But i think 'The Beginner' (and I) were referring more to the drop in chain height caused by jumping to the inner front ring causing the chain to literally drag itself over the part of the front derailler that joins the left side to the right side, as opposed to lateral drag where the chain touches one side or the other of the derailler due extreme angles/poorly set up derailler. Has more of a 'ratcheting' sound to it.