Chains 101; Wear and Care

[steventh]

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Disclaimer.

This information is from various sources on the internet. It has not been verified. I am not an engineer or mechanic or have any other specialised knowledge of this topic. This information and any conclusions I make could be incorrect. Do your own validation of this information before you use it.

In all cases follow your manufacturers recommendations.


Chains, Belts or Shaft?

Chain drive uses sprockets and a roller chain, which requires both lubrication and adjustment for “stretch” that occurs through wear. They transmit power very efficiently. Motorcycles are one of the most demanding applications for a metal chain as they often handle high power and speed and are exposed to a large volume of contaminants and extreme environmental conditions. Though Hans Renold is credited with inventing roller chain in 1880, sketches by Leonardo da Vinci in the 16th century show a chain with a roller bearing.

A belt drive is still subject to stretch but operates very quietly, cleanly and efficiently. They do not require lubrication. Belt drives are limited in the amount of power they can transmit. A toothed belt is frequently used. They usually last longer than chains but are more expensive to replace.

A shaft final drive is housed within a rear swingarm. This arrangement is superior in terms of noise and cleanliness and is virtually maintenance free, with the exception of occasional fluid changes. However, the additional gears required are a source of power loss and added weight.


Pitch and O / X Rings

Chains are precisely made devices. The distance between the links is the pitch. 520, 525 and 530 chains have the same pitch.

The O or X rings were a major advance in chain design reducing the frequency of lubrication and reducing wear by keeping the lube on the chain for longer and keeping debris away from the moving parts. These soft rubber rings are easily damaged so care is needed when maintaining the chain.


Lubrication

All chains – even “O” and “X” ring chains need lubrication and occasional cleaning. This has the greatest influence on chain wear and therefore serviceable life. The outside and the inner surfaces between the pins and bushings and the bushings and rollers require lubrication.

Ensure you use lubricant that is suitable for O ring chains. Other lubricants (including WD40) may dry out the O rings and increase chain wear. Wax type lubes have minimal fling-off but tend to collect dirt and are best applied on a warm chain. Oil type chains tend to fling onto the wheel rim but do not collect as much dirt as the wax types, application onto a warm chain is preferred.


Worn Chains

A worn chain, apart from the risk of breaking or skipping off the drive chain, leads to an increase in the rate of wear of the sprockets with which it mates. The sprockets cannot change the spacing of their teeth to match the increasing spacing of the links or "pitch". It grinds a characteristic hooked shape into the rearward face of the sprocket teeth.

Chain wear is rapid early in the chains life (20 hrs); it then wears slowly until near the end of its life when the wear rapidly accelerates again. If you remove all the lubricants with solvents, the wear progresses along a nearly straight line and the life of the chain is shortened


Chains Wear, Not Stretch

Chains do not stretch. The “stretch” is due to wear between the pins and bushes. This increases the spacing of the links causing the chain to grow longer. (There is some argument that they stretch in the first few hundred ks with at least one manufacturer selling “pre-stretched” chains though this may be the rapid early wear described above)

Parts of the chain can wear at different rates giving the appearance of a loose / tight spot when the wheel is rotated. The area of greatest wear is where the chain is the loosest and this is where the maximum stretch should be measured.

A new chain will not have any play along its length whereas a worn chain will.


Wear Limits - 1.5%

Chain wear should be measured at the loosest part of the chain as this is the area with the greatest wear.

The specification on stretch limits that seems to be accepted is 1.5% but commentary varies this from 1% to 3%. Testing shows that when wear elongation is less than or equal to 1.5 percent for a transmission chain there is almost no risk of fatigue failure.

Suzuki makes it easy for the Hayabusa; for both Gen1 and Gen2 the maximum permitted length between 21 pins (at their centre) is 319.4mm. Some bikes have replacement marks on their swingarms. Remember, the greater the stretch the greater the wear on the sprockets.

A simple and effective method of checking for chain wear is to pull the rearmost link on the back sprocket away from the sprocket. A worn chain will lift a little off the sprocket. If the gap between the sprocket and the roller is greater than 1.5mm the chain should be replaced. As with all wear measurements make sure the loosest part of the chain is on the rear sprocket when you test it.


Sprocket Wear

It is often not necessary to replace the front and rear sprockets when the chain is replaced despite what your mechanic says. Commentary suggest that sprockets can be replaced every second chain. Of course this depends on the wear in the sprockets (determined by how long a worn chain has been used). Inspect the sprocket before deciding if they need to be replaced.

If they are not “too” worn this should have a minimal impact on the life of the chain.


Method – Chain Cleaning (every 1000km though you may choose to do this every second lubing)
This can be easily done with the chain on the bike.

Never go near your chain while the engine is running (even if out of gear). Look on U-tube if you want to see amputations caused by fingers getting caught in rotating chains.

1. Secure your bike with the back wheel a clear of the ground.
2. Put your bike in Neutral so you can turn the back wheel by hand.
3. Measure the chain for wear and inspect (rust spots, cracked plates, loose or rotated pins, binding links). Ensure the master link is in good order. Replace chain if required.
4. Spray or paint (with a soft brush) on to the chain appropriate cleaning fluid suitable for O (x) ring chains while you rotate the back wheel. Kerosene is excellent. Do not use highly solvent fluids such as WD40 or high pressure water that can force the existing lube out of the links.
5. If the chain is very dirty clean with a soft brush so that the o rings are not damaged.
6. Wipe the chain with a cloth to remove all cleaning solution and dirt prior to lubing.
7. Check the chain alignment and free play according to your ownerâ€s manual.


Method - Chain Lubing (at least every 1000km, more in wet weather or hard conditions / service)
This can be easily done with the chain on the bike.

Never go near your chain while the engine is running (even if out of gear). Look on U-tube if you want to see amputations caused by fingers getting caught in rotating chains.

1. Take the bike for a short ride to “warm” the chain
2. Secure your bike with the back wheel a clear of the ground.
3. Put your bike in Neutral so you can turn the back wheel by hand.
4. Measure the chain for wear and inspect (rust spots, cracked plates, loose or rotated pins, binding links). Ensure the master link is in good order. Replace chain if required.
5. Ensure the chain is relatively clean (it does not need to be cleaned every time it is lubed)
6. Spray the lube on the inside of the chain plates on each side of the chain as you rotate the back wheel. Apply a liberal coating but do not overspray as it will just be flung off.
7. Ensure the O rings, and rollers are lubricated.
8. Do not use the bike for 10-15 minutes to allow the lube to “set”.


The Life of a Real Chain.

Below is a picture of the worn chain that was replaced at approximately 30,000km. I donâ€t know how often the chain was lubed prior to my owning it at 15,000km (I suspect not often due to some rust spots indicating no lube). However it has been lubed at the earliest of each month or 1000km since then.

   

This chain had several tight spots which was the main reason for replacing it. Some parts of the chain were “in spec” while some were out.

As you can see from the picture above the chain has “stretched by 5.5mm or 2% compared to a new chain (301.5mm vs 307mm). This means that by the 19th link the old chain is app 1/3 link longer than the new chain (see pic below). This increases wear on the sprockets as the force is concentrated on fewer teeth and not evenly across the teeth on the sprocket.

   

The wear occurred in the pins and bushings and not stretching of the side plates. A worn pin in this chain was 5.04mm diameter compared with a new pin of app 5.22mm. Interestingly the worn pin and its bushing had no lubrication despite being regularly lubed and it being an X ring chain. This may be because the previous owner cleaned the chain with high pressure water or harsh solvents (and I need to be a little more generous with the lube!)

I did not replace the sprockets with the chain as they did not show wear.

Cheers

Steventh

[BUSGO]

That just about says it all Steven.
Good post mate.

[Pommie]

Nice post Steven, just replaced mine too as it happens

[Volvi]

great post i even learned a few pointers.

[GRUNTMAX]

Very sorry, didn't read it all, probably will later. I reckon if you keep it clean & lubed & adjusted right & change it every 25,000kms you'll be right. Do that and there's a good chance it won't kill ya, because that's what a neglected one can do.

[fasterfaster]

It is often not necessary to replace the front and rear sprockets when the chain is replaced despite what your mechanic says.

Can't agree on this one ............. despite what it says ..........I'm afraid.
Firstly given the minor costs of sprockets compared to a quality chain replacement, it is cheap insurance on the money your new chain just cost you. Also sprockets may not appear worn at time of replacement, but in 10,000 K when your chain is still relatively new and sprockets are then worn it will accelerate your new chain wear and shorten it's life considerably. Replace as a set.