8 Causes of Sagging Bike Chain and How to Fix It

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The bicycle chain is an important component of a bicycle. With this chain we can move the bicycle as we pedal. This chain works by connecting the energy from the crank (bicycle pedal) to the sprocket (rear gear) that is connected to the rear wheel of the bicycle.

If there is a problem with the chain, the bicycle cannot move. One of the problems that is often found in bicycle chains is that it detaches from the chainring or even breaks.

Chains that often break will interfere the riding activities, because they have to get off the bicycle and had to dirty their hands with chain lubricant, not to mention the difficult installation. This is quite frustrating and time-consuming.

Frequent sagging chains can be an early indication of other bicycle damage. For this reason, it is necessary to carry out a detailed and routine inspection to prevent further damage. Identify the causes of sagging bicycle chains so you can find the correct solution. Usually sagging chains are caused by:

1. The Chain Is Too Loose

Chain installation that is too loose can make the friction frequency and the friction surface area of ​​the chain with the chainring become bigger. Due to excessive friction, the chainring will wear out quickly and causing the chain to break.

The chain can be detached due to the lack of traction, allowing the chain to shift from the chainring. In addition, when the chainring wear out, the possibility of the chain to change positions is even greater.

Solution: There are two ways to solve a sagging chain. The first is to move the tire slightly to the back and adjust to the sagging of bicycle chain. Loosen the rear wheel and adjust the position of the chain so that it does not come loose again.

The second way is to reduce the length of the chain by cutting the chain. For this second method, make sure you have the tools for cutting and reassembling the chain. Don’t cut it too short, if that happens it can cause other problems.

2. Rear Derailleur (RD) Settings

On bicycles that already have a gear acceleration system, the RD mounting position can be one reason the chain is sagging. This is because the RD limit bolt or screw setting is not correct. In the RD section itself there are two limiting bolts which are coded H and L.

The H bolt is located at the top to adjust the largest sprocket limit, while the L bolt is located at the bottom to adjust the smallest sprocket limit. These two limiting bolts play an important role in the shifting of the rear chainring so that they do not come off.

Solution: In order for these two bolts to function, then it needs to be set properly. The trick is to position the last sprocket then adjust the bolts according to the sprocket.

After that, remember to test it first and pay attention to the displacement of the chain whether the movement is going well or if it breaks. Take it to a bicycle repair shop, if this solution doesn’t work.

3. Front Derailleur (FD) Settings

FD with incorrect settings can also be the reason the chain is disconnected. In the FD there are also two bolts with the H and L codes. The function of these two bolts is the same as the function of the two RD bolts, only their position is close to the crank. The position of the FD bolt setting needs to be considered.

If the H limiting bolt is too loose, it can cause the chain to slide out of the crank, causing it to come into contact with the foot and pedal. On the other hand, if the L limiting bolt is too loose, the chain can slip into the crank and it can get caught in the frame.

Solution: To fix and overcome this problem, the method is almost the same as setting the 2 RD bolts. First by positioning the last crank, then set 2 FD bolts according to the crank position. And lastly, don’t forget to check the suitability of the position again.

4. Loose Shifter Cable

Loose shifter cables can also cause the bicycle chain to disconnect. When the shifter cable is loose, the RD and FD settings will automatically change from their original position so that the chain can be released.

Solution: If the shifter cable loosens, you can tighten the shifter cable again. Clean the cable from the dirt that sticks and provide lubrication or grease so that the shifter cable can function properly. After tightening, reset the 2 FD and RD screws of the bicycle according to the position of the shifter cable.

5. Chain Condition

This factor can be one of the main factors that causes the chain to break off. Chains that have worn out due to excessive friction or due to long chain life can cause the chain bite to be less than optimal on the sprocket and chainring so that it is very easy to release.

For this reason, it is necessary to periodically check the condition of the chain whether it is still suitable for use or if it needs to be replaced.

Solution: The solution to this problem is quite simple, you have to replace a bicycle chain that is no longer suitable for use. You can buy and pair directly at the nearest bicycle repair shop.

6. Chainring and Sprockets

These two bicycle components are also factors that can cause a bicycle chain to break. These two components can also wear out. The main characteristic if it is worn and unfit for use is that the chain often moves itself. This is because these two components are depleted and cannot withstand the chain movement.

Chainring and sprockets that have been thinned and sharpened can easily fit between the rollers and the inner plate of the chain so that the chain will break.

Solution: To solve the problem, it is necessary to replace the chainring and sprocket to a new one. We can buy these two components at the nearest bicycle repair shop and have them installed by the repairman.

7. Less Lubricant

Dry chains can make the chain performance less than optimal. Chains can move easily when they are dry because rough surfaces under certain conditions can push the chain out of the way.

In moist condition, the friction between the chain and the chainring or sprocket will glide smoothly.

Solution: Make sure to lubricate the bicycle chain regularly and periodically.

8. Errors in Chain Installation

Wrong installation will certainly affect the performance of the chain itself. Some of the things that go wrong in the chain installation including:

  • Chain installation that do not match the type or specification, for example a 10 speed chain attached to a 9 speed chain bicycle.
  • Inverted chain installation. Of course this is a pretty fatal mistake so the chain doesn’t work properly. For that, read the chain installation instructions first.
  • The chain connection is not quite right and fit. For example, there is a gap between the inner plate and the roller, or a rivet that is too popped out on one side so that it can easily knock the chain off

Solution: Before installing a bicycle chain, be sure to read and understand the guide on how to attach the chain. Readers can also ask for help from the closest person who knows about this or directly to the nearest bicycle repair shop.

So, those are the factors that cause the chain to break, along with the solution. Different types of bikes may have different solutions, so ask an expert if you don’t know how to fix it.

Before you use your bicycle, make sure the bike and its chains are in good condition so that you can enjoy your exercise with no worry.