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Motorcycle chains – everything you need to know

A quick guide towards understanding what motorcycle chains are and how they work.

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Typically, motorcycle chains come in either one of two forms – O-ring or X-ring tyres. Regardless of which, one that is worn out will either just sap power away at best or become dangerous at its worst.

Choosing the right chain depends on a bike’s power output and its weight. A chain needs to transmit the right amount of power to move the bike and a heavier motorcycle puts more strain on a chain.

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Most litre-class sportsbikes now run a 530-pitch chain as standard for road use, but regular trackday riders might consider the narrower 520/525 width chain as not only does it save on weight, it absorbs less power, generates less friction and is slightly smaller, but won’t last as long.

A chain setup that’s too tight will accelerate wear through excess pressure on the sprocket teeth, chain joints and shaft bearings. A slack chain, on the other hand, will also quickly wear and in use could have a whip-like action that may result in it snapping off.

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Either of these conditions will result in excessive chain elongation. This along with an increase in vibration and/or noise, will indicate when a chain is near the end of its life.

There are many factors which can affect chain wear, such as factory assembly accuracy, quality / condition / method of parts and lubrication. Even if you run a sealed roller chain, the best way to prolong its life is to clean it, externally lube it and perform proper regular adjustments.

Image source: Sportsbikes.net
Image source: Sportsbikes.net

O-Ring Type
O-ring chains have small rubber O-ring seals that sit squashed between the pin link and the roller link plates, forming a barrier that holds factory-applied lubricant/grease inside of the rollers. These seals also prevent contaminants and dirt particles from entering inside the chain linkages and causing wear.

Image source: Motorcyclistonline.com
Image source: Motorcyclistonline.com

When the lubricant between the O-ring and the link plate disappears, the O-ring will wear and deteriorate. O-ring seals are usually made from a common synthetic rubber called acrylonitrile-butadiene, chosen because of its oil, fuel, heat and abrasion-resistant properties.

O-rings create friction that absorbs horsepower. The link plates that hold the O-rings are under compression, so more force is needed to articulate the chain – therefore, the transmitted power is decreased.

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X-Ring Type
X-ring chains utilise an O-ring type construction that has an X-shaped cross-section. Its seals are flat-sided, so they have a greater contact patch with the sideplates. The X-ring’s four contact points create an extremely tight seal, keeping lubricant in and dirt out.

As a result, X-ring type seals have a lot less friction than O-ring seals because they do not have to be pressed as tight. This means the X-ring seals should last longer and retain lubrication within the chain for a longer time as well.

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Top-spec race chains don’t have any O or X-ring seals to avoid loss of horsepower through friction. In racing, longevity isn’t an issue as the chains are constantly changed by race team mechanics.

Co-founder of Bikes Republic and a motoring journalist by night. He is a self described enthusiasts with a passion for speed but instead rides a Harley and a J300. A man of contradictions, he is just as passionate about time off in the quiets as he is about trail braking into turn one at Sepang Circuit on two or four wheels.

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