Buying Guide: What Bike Chain Do I Need?

The bike chain is a critical component of your drivetrain, responsible for transmitting power from the pedals to the wheels. Essentially, it’s a series of interconnected links that rotate around the chainrings and cassette, enabling your bike to move forward.

Each bike chain is composed of two side plates held together by rivets, with a roller sitting on the shoulder of the outer link. Designed to endure the stresses of pedalling and shifting gears, a bike chain is built to be robust but will inevitably wear out over time, which is why it is useful to find out which is going to be the right chain to replace an old one with.

Types of Bike Chains

Bike chains come in various types, each tailored to specific bikes and riding styles. Here at Sigma Sports, we have a wide selection of bicycle chains from brands such as KMC, Shimano, SRAM and Campagnolo.

We also have chains suitable for all types of cycling including road, MTB, gravel and cyclocross as well as time trial and triathlon.

Chain Compatibility and Sizing

Ensuring your bike chain is compatible with your drivetrain is crucial for smooth shifting and preventing damage. The chain must match the number of gears on your cassette and the width of your chainrings. Additionally, the chain must be the correct length to maintain proper tension and avoid drivetrain issues.

You can use a chain checker to determine the correct chain size or refer to the manufacturer’s specifications. Chain width is typically measured in millimetres, while chain length is measured in inches or links. Using the right tools and information ensures your new bike chain fits perfectly and performs optimally.

Speed Chains

A speed chain is a bike chain designed to work with specific numbers of gears or "speeds" on a bike's drivetrain, such as 9-speed, 10-speed, or 11-speed systems. These chains are narrower and precisely engineered to fit the corresponding cassette and chainrings, ensuring smooth and efficient shifting.

How to fit a new bike chain

• New bike chain
• Chain tool (chain breaker)
• Chain link (quick link or master link)
• Chain checker
• Chain lube

Your chain is a key element of your bike’s transmission, linking the front part of your drivetrain (the pedals, cranks and chainrings/sprocket) to the rear (cassette/sprocket and rear hub). It’s through the chain that pedal power is converted into forward movement, so it’s essential to buy the right one and to keep it maintained.

Modern chains are properly called ‘roller chains’, and consist of short cylindrical rollers held together by side links. The gaps between the rollers mesh with the teeth on a sprocket or chainring, to drive the transmission when turned. Most bike chains are made of alloy steel for strength but some performance models may feature high-end alloy parts or hollow pins/side plates to save weight.

Step-by-Step Guide To Fit a New Bike Chain:

Remove the Old Chain:

• Shift the bike to the smallest chainring and smallest rear cog.
• Use a chain tool to push the pin out of one of the links on the old chain, or remove the quick link if it has one.
• Carefully remove the old chain from the drivetrain.

Measure the New Chain:

• Lay the old chain next to the new chain to measure the length.
• Ensure both chains are fully stretched out and the new chain is properly aligned.
• Mark the link where the new chain needs to be cut.

Cut the New Chain:

• Use the chain tool to push out a pin from the new chain at the marked link.
• Be cautious not to lose any parts if your chain has a quick link.

Fit the New Chain to the Bike:

• Thread the new chain through the rear derailleur, starting from the front chainring.
• Make sure the chain runs smoothly through the jockey wheels and around the cassette.

Connect the Chain:

If using a quick link:

• Insert each half of the quick link into the ends of the chain.
• Pull the chain tight until the quick link snaps into place.
• Pedal backwards and apply pressure to lock the quick link fully.

If using a chain pin:

• Insert the special connecting pin provided with your chain into the end of the chain.
• Use the chain tool to push the pin through the link until it's flush with the outer plate.
• Break off the excess pin with pliers.

Check the Chain Length:

• Shift the chain onto the largest chainring and largest rear cog.
• Ensure the derailleur is not overly stretched or slack when in this gear combination.
• Adjust the chain length if necessary by removing additional links.

Lubricate the Chain:

• Apply a suitable bike chain lube to the new chain.
• Wipe off any excess lube with a clean cloth to avoid attracting dirt.

Final Inspection:

• Check that the chain runs smoothly through all gears.
• Ensure there are no stiff links and that the chain moves freely.

Which chain is right for me?

The type of chain you need will depend on the type of bike you are riding. Many different chain widths are available to fit different road and MTB drivetrains (e.g. an 11-speed cassette requires a different chain to a 9-speed one – the chain must be thinner to fit into the narrower spaces between the sprockets)

When replacing your road or mountain bike chain you need to get one that matches the number of gears in your drivetrain.

Chains for Gravel, Mountain and Road Bikes

The amount of sprockets on your rear cassette – 9, 10, 11, or even 12 – is crucial. Because the distances between the sprockets vary on different ‘speed’ cassettes (e.g. the gap will be wider on a 9-speed block than on an 11-speed), you need a chain that fits. A chain for an 11-speed transmission will be narrower than one for a 9-speed, etc. It is important to match the correct speed chain to the respective number of cogs on the cassette for optimal performance.

Generally chains and cassettes from different manufacturers will be cross-compatible with each other, although Shimano and SRAM chains will not work very well with Campagnolo cassettes, and vice-versa.

It is also worth noting that some chains (e.g. Shimano) require special rivets to rejoin them once they have been split, and the old rivets cannot be used again. SRAM chains use a special ‘Powerlink’ ‘that can be split and rejoined without the need for a special chain tool, making them a popular choice even on non-SRAM transmissions. Additionally, the flattop chain in SRAM's 12-speed groupsets has a unique side plate design and compatibility restrictions with other components.

Bike Chain Recommendations

We asked some of the Sigma Sports product experts for their bike chain recommendations, based on the chain they would select for their own bike: 

• Best Road Chain (12 Speed for top-end Road groupsets) - KMC TT12 Waxed Chain 126L
• Best MTB Chain (12 Speed top-end MTB groupsets) - KMC DLC 12-Speed Chain
• Best Value Chain (11 speed for mid-range Road and MTB groupsets) - KMC X11 Grey Chain 118L

All new chains are longer than necessary and will need to have links removed, a straightforward job easily tackled by most home mechanics, but if in doubt about chain sizing or fitting, have a professional do it for you.

How do I know when I need a new chain?

All chains have a limited lifespan. Every time a link of a chain drops into the valley created between the teeth on a cassette, sprocket or chainring, two metal surfaces rub together. Add in the grinding paste that a transmission attracts and multiply by the hundreds of times this happens every time you turn the pedals, and you have a recipe for wear and tear.

Time to Replace Your Chain

As chains wear out they tend to stretch, and eventually, you may start to experience 'chain skips' as the chain skips over the teeth on the sprocket when under load, instead of meshing with them as they should.

Once this happens it is time for a chain replacement (and perhaps a new cassette and chainrings too, if the wear is considerable). However, you can act earlier by using a chain measuring device to determine if your chain is beginning to wear – catch it quickly and you only need a new chain.

Another – less accurate way is to measure by sight. Lean the bike against a wall, drive side facing outwards, and ensure your chain is shifted onto the smallest rear sprocket and largest front chainring. Now take the chain between your thumb and forefinger at the 3 o’clock position and pull towards you gently. If the bottom jockey wheel of the rear derailleur moves, it’s time for a new chain.

Chain Maintenance and Care

Whatever bike you ride, chain maintenance is key. Chains will wear and stretch over time, and a worn chain will damage the teeth on your chainrings or sprocket. It’s important to keep your chain clean and lubricated to minimise wear and to regularly check chain length so it can be replaced when necessary. Using a chain breaker tool is crucial for making precise adjustments to chain length and for removing damaged links.

Regular maintenance is key to extending the lifespan of your bike chain and ensuring reliable performance. Here are some essential tips:

Clean Regularly: Use a chain cleaner to remove dirt and grime, then dry the chain with a rag.

Lubricate: Apply a thin layer of chain lube to reduce friction and prevent rust.

Check for Wear: Regularly inspect your chain for signs of wear and replace it when necessary.

Use the Right Tools: A chain tool can help you remove and install the chain correctly.

Avoid Harsh Chemicals: Steer clear of abrasive materials and harsh chemicals that can damage the chain and other components.

By following these maintenance tips, you can keep your bike chain in top condition, ensuring smooth shifting and a longer lifespan for your drivetrain.

How to Wax a Chain: Guide for Road Bikes

Cyclists, of all levels, constantly strive for better performance; from both ourselves and our bicycles. While almost every bike component can be upgraded to shave weight or achieve a better aerodynamic profile, one key element to consider, which is often overlooked, is the efficiency of your drivetrain. An efficient chain can yield impressive watt-saving results while delivering a smoother, more enjoyable riding experience.

Clean Your Chain Thoroughly

A clean bike is a fast bike, and a clean drivetrain is a fast drivetrain. Dirt and grime picked up from the road create friction which impedes optimum power transfer. Use an effective degreaser to remove grime and degrease your chain, such as the one below:

Finish Line Citrus Degreaser 355ml Aerosol

Simply spray degreaser onto a rag, and run your chain through it by back-pedalling your cranks which degreases and cleans the chain. If you have a workstand, it will make the whole process a little easier.

Your chain will come up sparklingly clean, with no dirt or grime to impede power transfer or shifting performance. It is now imperative to lubricate the chain efficiently; and that’s where some serious watt savings can be made.

Lubricate with Wax

Not all lubes are created equal, and test results have shown that the very best chain lubricants can yield an efficiency saving of over four watts compared to the least efficient. Consistently, hot paraffin wax has come out on top as the most effective chain lube in tests. However, the messy, time-consuming, and somewhat dangerous endeavour of melting the wax means the method is not widely used.

There are now hassle-free chain waxing options, such as this KMC Chain Wax 150ml, which can be applied directly to the chain while it is still attached to your bike and unlike traditional time-consuming waxing methods, it’s quick and easy, improves efficiency and has the benefit of not attracting dirt and grime, and thus extending the lifespan of your chain.

Easy Application to the Bicycle Chain

With your chain in the big chainring and a middle cog on the cassette, apply wax against the upper of the chain and turn the cranks in an anti-clockwise direction to apply the wax to the rollers for about three full chain lengths. Repeat on the lower side of the chain - there’s no need to apply to the sides of the chain. For a more thorough application, gently pinch the wax deeper into the rollers. You can use a plastic bag to keep the product off your hands if you prefer. You’re ready to ride with a silent, efficient, watt-saving chain.

A wax lubricant can be applied to any drivetrain; from entry-level to top-end, expensive chains, including systems with ceramic bearings and oversized jockey wheels. This means you can benefit from the same improvement in performance regardless of your setup. What’s more, the cost per watt saving represents astounding value compared to other drivetrain upgrades.

Keep a Clean Chain

Wax doesn’t attract or hold road dirt and grime as readily as traditional lubricants, so your drivetrain stays cleaner for longer. By regularly reapplying, you don’t even need to use a wax solution; simply wipe the chain down with a rag and reapply your wax. The only downside is the wax can be washed off in a torrential downpour.

Summary

To ensure optimal bike performance, regularly check your chain for wear and replace it when necessary. Choose a chain that matches your bike's drivetrain specifications, such as the number of speeds. Proper maintenance, including cleaning and lubrication, will extend the life of your chain and improve your overall riding experience.

We have a wide range of bike chains and drivetrain components, and our experts will be happy to answer any queries you have.