Maintaining your bike’s chain
The drivetrain on most bikes consists of a chain and sprockets. Exposed to the elements, they require regular checks and maintenance.
A correctly-adjusted and well-lubricated chain drive is very efficient at transferring power. The problem is that it’s exposed to the elements, and dirt and dust sticks readily to the grease.
Keeping the chain clean, lubricated and adjusted pays dividends in longevity, smooth power delivery, performance and economy.
Clean the chain and rear sprocket every 1,000 to 1,500km using a chain cleaning spray and a stiff nylon brush. A purpose-design three-sided chain cleaning brush is best. Once clean, wipe away any residue with a clean cloth. Allow the chain to dry off before applying chain lube.
Never try to clean the chain when the engine is running. Always rotate the rear wheel by hand if on a centre stand or paddock stand, or roll the bike along.
The front sprocket is usually hidden away and tends to build up a coating of dirty grease in its housing. Undo the cover and clean it every other time you clean the chain.
Axles often have castle nuts with a split or cotter pin. Always replace with a new pin once you’re happy with the adjustment.
Give the chain a squirt of lube every 300km, and fully lubricate it after cleaning at the 1,000 to 1,500km mark. It’s best to lube the chain after a ride, not before, because the lube will better penetrate the hot links.
Spray lube on the inside run of the chain, not the outside where it will just fling off. Aim to get lube between the inner and outer plates and in between the rollers and side plates.
Check the chain adjustment every time you clean your bike. The user manual will detail the correct amount of slack, as well as how and where to measure it. Things to do:
As chains wear the slack will increase. If your measurement show the opposite, it may be that the chain has developed a tight spot and will need to be replaced.
Adjusting out the slack:
Turning the adjusters by one flat or sixth may be all you need but, if not, you’ll now have a gauge of how much difference it will make to the chain tension. Try not to overtighten, because it can be tricky to go back.
It’s important that you measure the slack the same way after adjustment as before. The bike on its wheels and the axle nut done up to the correct torque.
The chain and sprockets should be inspected for wear every 10,000-12,000km. How you ride can have a big effect on the chain. The harder you accelerate, the more you stretch it.
Checking the sprockets for wear is done visually. The rear sprocket is usually first to go, but sometimes not by much. The easiest tell-tale is on the tips of the sprocket teeth. There should be a discernible flat on them. If any are worn to a point, the sprocket is well past it and needs replacing. Other signs are teeth worn into hook shapes or rounded off.
If the rear sprocket does need replacing take off the front sprocket cover and inspect it too. It’s often worth replacing both anyway. It’s likely the chain will have worn out too.
To check chain wear:
If it passes those tests, the process is then the same as checking chain tension, only you must do it over the whole length of the chain. This needs rotating the rear wheel, so a paddock stand is the best option. You can use a centre stand but the actual slack measurement might not be wholly accurate. However, what we’re looking for here is consistency between the measurements, so it will still work.
Measure the slack every 20cm or so until you’ve made a complete rotation of the chain. Mark where you started with a blob of white-out or grease on the side plate. If the slack measurements vary by more than 10mm the chain needs replacing. Make sure the sprockets are good before doing so.