Road grime, salt, sand and dirt will wear a bike chain quickly. This leads to premature stretch, noise and a distinctly unpleasant feel. I find this much more noticble when riding fixed gear than road bikes.
To keep the chain in top condition, clean it regularly. I often notice a noisy ride right after it has been raining. I'm guessing the rain has washed off any remaining oil and the road spray has left a sprinkling of grime from the road. Don't be tempted to oil a dirty chain - the oil will carry the dirt in deeper. Get home and remove the chain. If you don't have a quick release link, get one. The KMC ones are best I find.
Mix up the following ingredients and drop the chain in. I use a can with a screw on lid and slosh the fluid around.
| 40% methylated spirits | General solvent. If you've drunk all the meths, hand sanitiser, petrol, vodka, lighter fluid etc can be substituted. |
| 20% washing up liquid | Detergent to break down the oil |
| 10% lemon juice | Helps with degreasing |
| 30% water | Add enough so all the chain is submerged |
| Baking soda | Shake in a bit until it fizzes up. This releases the dirt from within the chain |
I've used a solution along these lines for around 10 years and find it most effective. I tend to leave the chain in a couple of hours and swirl it around a bit. Rinse it off and check it for any gritty residue. Potientially a second dip is necessary (especially if the solution is a couple of years old.) It keeps going for years. Lube the chain up and you're ready to go!