How Do I Know When To Replace Crankset?

By Rachel Lee
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Do you use your bike for commuting daily or you are a weekend rider who enjoys taking his fancy two-wheeler for a weekend trip? Whichever is your case, the crankset will eventually wear off at some time or the other, and need a replacement But, how do you know that the time has come?

The answer lies in being alert and looking for signs of a worn-out chain, cassette, and chainring teeth. Many experts believe that the most essential thing is the chain, and by replacing a worn-out chain, you can probably add more years to your chainrings and cassette, thus save money in the long run.

However, the truth is that cassettes, chainrings, and chain, all wear together. If a rider uses the same chain for too long and does not clean or lubricate the drivetrain regularly, the replacement costs may get higher later on.

For the healthy life of your crankset, it’s important that you keep a close check on the cassette and chainring. You may use the various chain checking tools such as the Park Tool Chain Wear Indicator to check the service life and determine when it’s time to replace.

4 Things That Can Go Wrong With Crankarms

There are mainly two types of crank arms on a bike that are connected to the bottom bracket to the pedals. Some bikes only have a one-piece crank that combines functions of the bottom bracket axle and the cranks. Here are the four things that may go wrong:

  • When the mating hole starts wearing often, the user often has to retighten it too many times resulting in the crank arm sliding too far. This often leads to a crack in the weakest part of the bottom bracket.
  • The mating hole designed to fit the bottom bracket often frets and fails to give a compact fit. You may notice a creaking sound on the power part of the stroke.
  • The threads for the pedal often get damaged or stripped to the point that the pedal stops working
  • The crankarms may often bend or twist due to an impact from an accident or fall. This is unusual and rare because the crank arms are stronger than frames.

Even if you follow expert advice closely and take good care of your crankset, you may still need to change the cassette or chainrings, sometimes at the same time. We recommend doing it together to ensure that you are not running a new chain on a worn-out gear, or else you will not be able to enjoy the optimum benefits.

When you notice chain skipping under load, worn cogs, or tooth shapes, these are clear signs that you need to replace your cassette. Sometimes, it’s hard to notice the changes in shape until they have gone beyond their lifespan.

Below we have discussed about some of the common signs of wear in cassettes and chainring, to help you determine when to replace them. It takes a bit of understanding and judgment, hence these tips come handy.

Signs of Wear In Cassette 

The best way to find out whether or not the bike cassette is worn out is simply to get a new chain installed. If you see the chain skipping while pedaling under load then this implies you need to get a new cassette. You must be careful while doing this test so that the skipping chain does not injure the rider.

There are a few cassette checking tools available in the market, but they tend to be subjective in nature. Almost all of them use a similar principle of applying the load to worn-out cassette teeth to see if the chain skips provide a similar result.

If you need to replace the cassette, this is going to be a fairly straightforward job as it only takes a few minutes, but you need a few special tools like a lockring tool, a chain whip, and also a cassette tool.

Signs of wear in Chainring

When the chainring becomes rough (like that of a shark’s fin) and noisy, it’s a clear indication that you need to replace it. Unfortunately, it is hard to tell visually that a chainring has gone bad until it is well past its normal service life.

The inner chainring is considered to be worn out when you install a new chain and it begins to chain suck. The outer chainring seeks a replacement when it becomes very rough running or the shifting gets inconsistent. It takes a bit of judgment for the beginners and expert riders know it just like that.

A quick tip is to check if you can see the daylight between a new chain and teeth. If yes then the chainring is most likely worn out. We suggest that you change the chain at the same time as the chainset and/or cassette as a worn chain on a new cassette may accelerate any damage. As the chain is a relatively inexpensive part of a bicycle, most experts recommend that you install a new one when replacing a cassette or chainring.

Related Questions

How long do cranksets last

With regular maintenance, the arms and spindle usually last longer than four years. The bottom brackets and chainrings will need to be changed along the way.

Does the size of the chainring affect speed

If you have a small chainring, this means you can climb easily in the lowest gear. With a bigger chainring, you can go faster in the highest gear. The best method is to calculate the gearing ratio by simply dividing the teeth of chainring with the teeth of the cog on the cassette.

See Also:
How Many Gears Does A Road Bike Have
5 Best Groupset For Touring
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