# How to Calculate Chain Length?

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Picking the right chain length for your bike is an important task that needs to be done when you make a new purchase.

The first step is to check your existing chain and measure it from the center of the pin on one end to the pin at the other end, including any extra links added. Knowing this number will tell you how many links your chain has now and can help you in deciding how much extra length you will need when purchasing a new chain.

A new typical chain will have 12 links and will be 12 inches in length.

It’s always better to go with a chain that has just enough excess on it so that it can be used rather than trying to hook two shorter chains together.

Too much excess length can potentially cause skipping during shifts or, worse – could damage the drivetrain itself.

In order to calculate the chain length, begin by wrapping the chain around the largest sprockets on the front and rear of it, making sure that both ends meet.

Ensuring that you don’t run the chain through the rear derailleur is essential at this point. From there, position the chain links onto each chainring’s teeth and adjust until you have approximately one extra inch of slack in the chain.

## Methods to determine your bike chain length

### 1- Classic Old-School Approach

Under this method, simply measure your old chain and use the same length for the new chain.

Measuring your old chain for a new one is the easiest way to ensure the optimal performance of your bicycle.

Start by shifting your bike to the smallest sprockets, and be sure to check for any slack or too much tension in the chain. If there is no slack, but the derailleur doesn’t pull back far enough, then you have determined that your old chain was the correct size.

To double-check this measurement, you can then shift to the largest front and rear sprockets. The chain needs to transition easily between these two sprockets with just two slight bends at each pulley.

After verifying this information, you can confidently move on to taking off the old chain and cut the ne chain accordingly.

### 2- Cog and chainring Approach

The method uses the largest cog to largest chainring approach to determine bike chain length.

To do this, the first step is to shift the front derailleur to the largest chainring and the rear to the smallest.

Then take the chain and wrap it around the largest cog at the back of your bike, making sure the end with an outer plate faces toward your bike’s front chainring.

Finally, pull this end of your chain through the cage of your front derailleur and place it onto the largest chainring, situated at about five o’clock.

If you are using a master link style of chain, you’ll need to install half of it onto the front end of your chain in order to account for that extra half-link.

### 3- The Scientific Equation Method

I call this the scientific equation method because it uses an equation to calculate chain length.

The equation is as below:

L = 2C + F/4 + R/4 + 1

This equation can be used to calculate a stay chain length greater than fifteen inches.

L = bike’s chain length measured in inches

C = Bike’s chain stay length measured in inches

F = It represents the number of teeth on sprockets

R = It represents the number of teeth on the largest rear cog

## Chain types

These are the evolution of the trusty master-link chains from days past. If you were lucky enough to ride a single-speed bike in the ’60s or ’70s, you could appreciate how much easier SRAM’s version was to install and remove. They are designed to open with a simple click and snap back into place securely after installation. Not only that, but they provide superior durability, which makes them suitable for modern multi-gear bikes as well.

### 2- Shimano and Campagnolo-type chains

Not only do they deliver a smooth and efficient ride, but they are also equipped with special replacement pins for quick installation.

You can be sure it will last for many miles because it’s made from top-end materials that meet or exceed the industry standard.

### 3- Chains with reusable rivets

Although some chains use pins for repair, having reusable rivets in the chain makes things a lot more convenient. This type of chain does not require replacement pins, as the partially pressed-out rivets can easily be plugged back in with a simple chain tool. So if you’re looking for an easy way to keep your bike’s chain up and running, then getting one with reusable rivets might just be the best option for you!

## After measuring, Replacing & Reassembling the bike chain

Below are steps assuming you have an SRAM power link chain:

• Once you have measured your bike chain, remove any extra links using a chain tool
• Grab and bring both connecting pieces that make up the master link
• Snap the master link together by connecting one piece from the inside of the chain and another piece from the outside Press the pins on both pieces through the rollers in the links
• Now snap the master link together
• Press the pins into place and pull tight to ensure it is secure
• Add a final visual examination for good measure, and you will be riding smoothly

For Shimano- or Campagnolo-type chain, below are steps to reassemble your chain:

• Remove any extra links from the chain
• You need to connect one piece from the inside of the chain and another piece from the outside with an inner link-only connection
• Make sure when the two ends of the chain come together, you insert the replacement pin just far enough to hold it together while it is in the chain tool
• The head of this special pin looks like a tapered rocket ship and should be inserted first into each link before pressing it further with a chain tool

For chain having reusable rivets, below are steps to reassemble your chain:

• All you have to do is grab the two connecting pieces and join them together in the chain tool
• Then turn the handle until the rivet is pressed into the chain – making sure each side of the chain has an equal amount showing
• Once you’re done, simply remove the chain tool from the chain, and it’s good to go

## Taking care of Your Bike Chain

Taking good care of your bike’s chain is one of the most important things you can do to ensure its longevity.

Since the chain is exposed and close to the ground, it attracts dirt, grime, and other particles, which can cause wear and tear if not tended to promptly.

An effective way of tackling this issue is to clean your chain both after every ride and more thoroughly once a month. It is usually safe enough to clean your chain while it’s still on the bike unless it gets particularly dirty or has gone too long without proper maintenance.

The combination of regular simple cleanings and occasional deeper cleanings will help your bike’s chain stay in prime condition for longer!

## Sum Up

While there are a few different ways that you can calculate the length of chain needed for your bike, it’s up to you if you want to stick with using the old school approach, scientific equation method, or cog and chainring approach. It is important to pick the right chain length for your bike so that you can avoid any damage to your drivetrain.

After you have measured and replaced your bike chain, be sure to take care of it properly so that it lasts as long as possible. With proper care, your bike chain should give you years of smooth riding.

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