Did you know that the chain is the most consumable part of a bike’s drivetrain system? Since chains are cheap, knowing the right time to replace them can reduce further damage on other pricey drivetrain components, thus saving you money in the long run.
Chain wear, also known as chain stretch, occurs with extensive cycling. When this happens, the chain may fail to engage with the teeth on the gears. If cycling is continued under this condition, the chain may slide up over the teeth into the next alignment reducing the power it is supposed to produce.
What causes a bike chain to overstretch and wear out?
• The primary and obvious reason is the continued use of the bike- If you are especially used to climbing with the bike, the chain is prone to degradation due to the forces that work on it. From a time/age standing, you can change the chain after 3-5 years, or immediately you notice pitting or rust on the chain. If you consider the typical road usage, chain replacement should be done after 8k-15k Kilometers, while for racing instances, 1k-2k Kilometers.
• Incorrect chain tension- If the bike came in with a poorly tightened chain, then it will not rotate as required and the result will be faster wearing out and inefficient cycling.
• Issues with lube and cleaning- Excess lube on a bike chain attract dirt that is abrasive to the chainrings, rollers and cassette, wearing them out. Regular cleaning of the chain and the entire bike removes the excess lube and eliminates the abrasion-wear problem.
Determining if the bike chain is worn out and overstretched
The easiest method: Put the chain on the larger ring, pull it to the front and check if it lifts for more than a few millimeters. If there is significant movement (1 or 2mm), then the chain is probably worn and stretched. This is the most straightforward way to know that your bike’s chain needs replacement.
You can also use a chain checker to know the stretching at which the manufacturer recommends a replacement.
As mentioned above, you should replace the chain as soon as you determine that it is overstretched to prevent damage to more expensive parts such as the cassette and chainrings. Note that if the teeth alignment is not symmetrical, you should replace them when changing the chain. Sprockets must be replaced when you are changing the chain, as putting a new chain on worn-out sprockets can lead to faster degradation of the new chain and tooth jumping, which is hazardous.