The chain is the component that connects the all the major components of your drive train. It's purpose is to distribute your leg power throughout the other components to produce forward momentum.

Briefly inspect your bike chain before every ride to make sure it's clean or at least adequately lubricated. Every few weeks or months, depending on the frequency of your riding, closely examine your chain for wear and chain stretch. You can purchase a special tool for measuring chain stretch. Certainly consider these as possible culprits whenever shifting becomes inefficient.

Checking your chain

• Pre-ride chain checks
  
  Rotate your pedals slowly backwards. Inspect individual chain links for build-up of dirt, rust and tight links. Tight links become very apparent as they pass through the curves of the chain's path.
  
• In-depth chain inspections
  
  For an in-depth inspection first remove your chain from your bike, thoroughly clean it by leaving it to soak in degreaser or a suitable solvent. Then, check carefully for wear and stretch.

Dirt causes various problems with your chain not least of which is shifting performance. It also:

• Increases the rate of chain wear
• The rate of wear and tear on derailleur and cassette cogs is increased 
• The flexibility of individual chain links can be affected

Cleaning a chain is a relatively simple process that needn't take a lot of time or effort.

Regular, on-bike cleanings

The simplest method for cleaning your chain on the bike is to use a Chain Cleaner. This simple to use piece of equipment should be a "must purchase" for every cyclist - it makes chain cleaning a doddle.

If you do not have a chain cleaner, simply scrub the chain with a firm brush, toothbrushes or nail brushes work well, and a good quality degreaser. 

Once cleaned and dried, re-lubricate with a chain specific lubricant. Teflon based lubricants that dry are best. If you use a lube that doesn't dry, remember to wipe off excess lubricant with a clean dry rag. Dirt loves a "wet" chain and especially one that is wet with oil.

Off-bike cleanings

Every few months or so, you can completely remove your chain, scrub it well, then soak it in solvent or degreaser, probably overnight. Make sure the chain is completely immersed in the cleaning fluid.

After removing the chain from the cleaning fluid, scrub off any remaining dirt with a firm, clean brush, and then dry the entire chain using a dry, clean cloth. After making sure that the solvent has completely evaporated, re-lubricate your chain and re-install. 

A note on chain stretch

If a thorough cleaning doesn't remove your shifting problems, and there are no other causes of the problem, your chain may be stretched and therefore in need of replacement. Chain stretch is normal and it can be there even if the chain appears to be in good condition. A worn or stretched chain can cause excess wear and tear on chain rings and rear cassette.

Got a problem? Find the answer

There are many different situations that cause shifting problems and which make your chain slip or jump. When the chain is to blame, there are two common culprits:

Tight links

These are chain links that don't bend efficiently as they pass through the curves in the chain path. The easiest way to spot them is to pedal your chain slowly backwards and watch as individual links pass through the tight turns of your rear derailleur. A stiff link will be very obvious.

Most tight links are caused by corrosion or dirt. Therefore they can often be fixed with a good cleaning, some re-lubrication, and a little flexing back and forth of the chain with your hands.

Other tight links can be the result of improper pin installation or serious chain damage. Poorly installed link pins can be worked back into position either by shifting them back and forth inside of their chain plates using a chain tool or flexing the chain. A damaged chain however should always be replaced.

A worn chain

Like most other parts on your bike, chains wear over time. As a chain wears the spaces inside each link (into which the teeth of your chain wheels or cogs fit) get longer and therefore cease to fit the teeth snugly. The only way to fix a worn chain is to replace it.