Monday, 20 January 2014

How to Stop Chain Rub / Noisy Chain

How to Stop Chain Rub / Noisy Chain- Intro

Chain rub is one of the most annoying noises. In a noisy city it is bad enough but when out enjoying more tranquil places such as park or country side, it can intrude on the enjoyment of your bike ride. Cycling up a hill often makes chain noise worse, due to more pressure on the drive chain, so when you are under stress pulling up a long hill, that noise  . . . uuurrgghh.

How to Stop Chain Rub / Noisy Chain - Noise from the Back

The cluster of sprockets (cogs) at the rear of the bike are known as the cassette. The rear dérailleur or rear mech can be cause of many different types of chain rub. Normally this is to do with a poorly adjusted rear mech.

There are 4 different ways you can adjust a rear mech to prevent chain noise.

1 - Chain noise / chain rub can be created when the chain is sitting too low (horizontally) on the smallest cog / sprocket.

2 - Chain noise / chain rub can be created when the chain is restricted (horizontally) from sitting on the largest cog / sprocket centrally.

3 - Chain noise / chain rub can be created when Indexing with gear shifter is not working properly.

4 - Chain noise / chain rub can be created when rear mech is set too high (vertically) or too low.

All of the above shouldn't really be faffed about with individually as they all have knock on effects on one another so you should readjust the rear mech completely. Following the below instructions.

A - Whilst turning the crank arm to simulate pedaling along, shift down (using the gear shifter on handle bars) to the smallest cog.

B - Now undo the cable clamp.

C- Now adjust high limit screw so that the upper wheel of the of the rear mech (small plastic cogs) is lined up perfectly with the smallest cog on the rear cassette.

D - Gently pull the gear cable to remove slack and then tighten cable clamp bolt.

E -  Now shift up (using gear shifter on handle bars) on to the second smallest cog, twist the cable adjuster until you hear the chain rubbing slightly on the 3rd smallest cog. Back off the adjuster until the rub stops, but no further.

F - You gears should no be indexed, the only thing that remains is to check the "low limit" so shift right up to big cog (sprocket) and that final lowest gear (biggest cog) should not require the gear lever to be pushed harder, nor should the rear mech push the chain past the largest cog, and in to the wheel spokes. Adjust the low limit screw until you have accomplished this.

G - Finally you may which to adjust the chain tension. Using the tension adjustment screw, the more you screw this is the tighter the chain will be, but it also means that less chain will be in contact with the sprocket which will increase wear in the long run.

This should sort out the noises from the rear in 90% of cases if the problem persists you can aslso try:

  • Check the drop out (the bit of the bike where the rear mech attaches to) has not become bent.
  • Check that the cage that holds the 2 small plastic wheels has not become twisted.
  • Check the small plastic wheels on the rear mech for wear (picture below).

How to Stop Chain Rub / Noisy Chain - Noise from the Front

First off I would recommend getting rid of your front mech. This may sound drastic but for 90% of users, you don't need it. 6,7,8 gears provided by the rear mech and certainly 9 and 10 gears provide enough gear range for every day use.

The problem is that even a well adjusted front mech will rub, when using certain combinations. For example using the biggest chain wheel (the cogs near the pedals), and the largest sprocket ( cogs near the rear mech), will normally cause rub, and noise.

If you would like to spend hours faffing with the indexing of the front mech then there are some instruction here. But I would just take it off, sell it on ebay, and use the money to by some food.

How to Stop Chain Rub / Noisy Chain - Noise from All over the place.

When was the last time you cleaned and oiled you chain? If its more than a couple of weeks, then a drop of oil or lube will not hurt, if its longer it may need a clean.

Chains do get squeaky when dry need oil.

Buying chain lube is a minefield, you can get squirty lubes like GT85 which is OK for light use, and certainly doesn't make much mess. Other offerings can be expensive such as various specialist lubes, which cost £6 for a tiny bottle. A wet lube last longer than a dry lube, but attracts more dirt . . . . .

If you have disc brake be careful not to get squirt oil on you brake disc! Buying drippy lube for bikes with disc brakes.

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