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Not many people will doubt the chain being one of the most crucial components of a bicycle. Hardly any other bike part goes through as much work as it does. That is why it is essential to keep a consistent check for any signs of worn or stretched bike chain.
Besides putting it at risk of snapping, a stretched bike chain also causes wearing out of other drivetrain components, such as the cassette and chainring.
So what are the symptoms of a stretched bike chain? Problems like frequent chain slipping, difficulty in shifting gears, and chain noise are the most common signs of it and indicators that you need to change it immediately.
This article will delve deep into the discussion of stretched bike chains. It will help you look out for common stretched bike chain symptoms and guide you about what to do in case you end up with a stretched bike chain.
What is a Stretched Bike Chain?
Though bike chains are usually said to be stretched after regular wear and tear, the term can be confusing. In reality, the chain itself can’t stretch. Instead of what people may think, the distance between chain links increases due to the breakdown/wear out of different components, which leads to the chain being stretched.
How is a Bike Chain put together?
To understand the idea of chain stretching, it is necessary to have a good understanding of how a bike chain is put together. The chain is composed of several small parts. These include the outer link, inner link, bushing, pin, and roller. These individual components collectively form a chain link.
Multiple chain links are integrated to form a bike chain. Chain links are connected in a way that the outer plate and inner plate alternate with each other. The bushing is normally integrated into the inner plate, holding in the circular roller.
The distance between two pins next to each other in a bike chain is called pitch. The industry standard for pitch in most multi-gear bicycle chains is 0.5 inches or 12.7mm (source). Any distance more than this means that the chain has started stretching. The most common type of chain wear occurs in pins and bushing.
Over time, the inner diameter of the bushings starts to increase, and chain pins begin to bend due to friction, heat, and weight. As a result, the pins do not sit as perfectly in the holes of the bushings as they do in a new bike chain. Hence, the side-to-side play in the chain increases.
The following is a table that shows the expected damage and urgency to replace the stretched bike chain, depending on the pitch.
|0.5mm||Good as new. No need for replacement.||Aligns perfectly with cogs and sprockets.|
|0.75mm||Has started stretching. Needs a replacement soon.||The rest of the drivetrain components are most probably fine.|
|1mm||Has stretched significantly. Needs to be replaced urgently.||Other components are expected to have taken some amounts of wear at this point.|
Symptoms of Stretched Bike Chains
It is advised to frequently measure your bike chain to spot any signs of bike stretching before the worn-out chain starts to damage the rest of the bike parts. The following are some of the symptoms which indicate that your bike chain is stretched and probably needs a replacement.
- Difficulty in Shifting Gears
Among many issues caused by a stretched chain, facing difficulty in shifting gears is probably the most common. For gears to function properly, the chain has to fit snugly into the gears. However, when the length of the bicycle chain increases, it no longer sits perfectly on the gear cogs.
A loosely sitting chain into the gears causes slipping and skipping while shifting gears. Moreover, the chain may not jump from one gear to another smoothly. This issue is more notable under circumstances when the workload on the bike is increased. It can be situations like going up a hill or accelerating from a stop. Not only can the chain skip while shifting gears, but it can also come off the gear teeth altogether, resulting in the rider losing control of the bike.
Apart from causing problems while changing gears, a stretched chain can also damage gear derailleurs. When the chain is not engaging with gear cogs properly, it puts more stress on the derailleurs. Thus, gears wear down quicker than they should, forcing you to make costly replacements.
- Chain Noise
Chain noise has got to be one of the most annoying issues for anyone 😡🤬. It can be frustrating and distract cyclists while they ride through the countryside. The reason for chain noise can be anything ranging from irregular lubrication, poor riding habits, or wear and tear. Among these, a common cause is elongated chain length or, in other words, a stretched chain.
When the chain is stretched beyond its optimal length, it puts extra stress on more or less every component of the drivetrain. As a result, the teeth of cassettes and chainrings begin to bend under excessive pressure. This is particularly true for riders who put a lot of mileage on their bikes or ride in harsh conditions such as dirt, mud, or sand.
The stretched chain and the damaged cogs collectively result in an uneven motion with a lot of friction. This not only causes chain noise but can further damage bike components at a rapid rate. The chain noise may start as a slight rattling sound, but it will soon grow and become a loud clanking noise that can be heard from a distance.
- Inconsistent Pedaling
A smooth and consistent pedal movement is a must for an enjoyable ride on any sort of trail. And for smooth and consistent pedaling, the chain has to move evenly on the cassette and chainrings with minimum friction. It allows the rider to exert less pressure while pedaling as well as control the bike effortlessly.
However, when the chain exceeds its optimal length, it does not align perfectly with the cogs or derailleurs. Consequently, the chain never settles down or acts appropriately. This misalignment leads to excessive friction between the chain and cogs. Hence, the rider has to exert extra force while pedaling and faces inconsistent pedal movement. Moreover, a stretched chain can also slow down the rest of the drivetrain parts that may be in perfect condition.
A Bicycle Safety and Information report by Bruce Burgess asserts that a sluggish chain and inconsistent pedaling movement can cause a higher fall risk as the rider is more likely to lose control (Source).
How to Replace a Stretched Chain?
Though the most sensible and economical solution to almost all bike chain problems is getting it repaired, unfortunately, a stretched bike chain cannot be repaired and has to be replaced. Moreover, the replacement has to be done immediately after noticing any signs of stretching in the chain. Otherwise, other parts, including sprockets and gears, may begin to undergo wear that will cost you a much more expensive repair or replacement.
Here’s how you can change your stretched bike chain:
- Start by making sure you’re in the lowest rear cog possible.
- Once you’ve downshifted, pull back on the derailleur, allowing some slack in the chain to release the pressure holding your chain in place.
- Many chains have a master link that may be used to free the chain from the cogs without breaking a link. For this, you’ll need a set of master link pliers. Squeeze the pliers around the master link until it breaks open. The chain should then slip straight out of your bike’s gears.
Now, to replace the stretched chain with a new one:
- Thread the chain back over the lowest cog and through the derailleur on your bike.
- Connect the master link to both ends of the chain and tighten it until it snaps into place.
- Make sure your chain is all the way on and that there is some strain in there.
- Then paddle the bike forward, and voila!
Keep your new chain lubricated. The chain is put under a lot of pressure while shifting gears. Let each link in your chain move freely to give it a head start. While changing gears, don’t exert too much pressure on the pedals. This is especially prevalent when cycling up a hill! Change down the gears before you hit the climb to put less pressure on the chain when you shift.
How to Measure Bike Chain Stretch?
Riders and experts use several methods to measure a stretched chain. The simplest and quickest one has got to be taking the chain off the front chainring and then using a ruler or measuring tape to measure the distance between two consecutive chain pins (pitch). However, if it’s precision and accuracy you’re after, using a tool like CC-3.2 Chain Checker is exactly what you need.
Method 1 – Assess the Space between the Chainring and the Chain
Manually measuring the stretched chain by taking it off is probably the simplest way to do it. To take the chain off, shift it to the largest chainring at the front and the smallest cog at the rear. Now try taking the chain off the chainring. If you notice a lot of space between the chain and the chainrings while you lift it, the chain has stretched by a significant margin at this point and needs a replacement. The method may not be as precise, but it gives you a good general idea about the health of your chain.
Method 2 – Use CC-3.2 Chain Checker
Tools like CC-3.2 Chain Checker are manufactured specifically to keep track of the stretch in bike chains. Locate the CC-3.2 end with a 0.5 stamp and align it with the chain in a way that the hook end is placed on an inner plate link. This will ensure that the measurement is made against the roller and not the side plates. After that, insert the other ends of the chain similarly.
If the end does not go in, it means the chain is yet to reach a 0.5% wear point. If the end goes in, it indicates a 0.5% stretch. A 0.5% stretch means a 0.5% increase in the chain length compared to when it was new. You can repeat the same procedure with the 0.75 stamp end to measure if the chain has reached the 0.75% chain stretch mark.
How to Avoid Chain Stretching?
As is the case with almost all bike parts, avoiding and taking precautions is always better than making replacements for a stretched chain. Here are some things to keep in mind to keep your chain from wearing down quickly.
- Frequent Lubrication
The most common reason for chain stretching is friction-related wear and tear. Lubricating your chain regularly can help to lower this friction and stop the chain from straining. Choose a lubricant that is suitable for your riding environment (wet, dry, or mixed), and apply it as directed by the manufacturer.
- Regular Cleaning
Chain stretching can also be caused by dirt and debris. Regularly clean your chain, then thoroughly rinse it with water and dry it before applying lubricant.
- Avoid Cross-Chaining
When you use the biggest chainring up front and the biggest sprocket in the back, or the smallest chainring up front and the smallest sprocket in the back, you’re cross-chaining. Your chain may experience additional stress, which could strain it and increase wear. Try to use the middle chainring in the front and change gears in the back to maintain a comfortable cadence to prevent cross-chaining.
- Avoid Gear-Shifting Under Load
Your chain may stretch and become more worn if you shift gears while riding vigorously. Try to change gears before accelerating or ascending, so the chain isn’t under as much stress.
- Maintain Proper Chain Tension
Your chain may stretch and get more worn if it is too loose. But, if it’s excessively tight, it can increase stress on other parts and reduce performance. Hence, checking your chain tension consistently and adjusting it as needed is necessary.
Here’s a summary of the symptoms of bike chain stretching and how to avoid it:
A stretched bike chain is something every new and experienced rider has to go through. It may not seem like a big issue, but if left untreated, it can harm other parts of the bike in no time. You should always stay alert to any signs of chain skipping, chain noise, or uneven pedaling, as these can be early signs of a stretched chain.