The drivetrain is one of the most important parts of any bicycle and also one of those that suffers the most wear due to the continuous friction between its components. Whether on mountain bikes or road bikes, proper maintenance of the drivetrain is key to prolonging its lifespan and avoiding costly breakdowns.
Elements such as the cogs, chainrings, derailleurs, and chain should be checked periodically, as the wear of one of these parts can affect the rest of the system. In addition, drivetrain components are not exactly cheap, so keeping them in good condition means long-term savings.
Drivetrain maintenance: easy and effective
The good news is that checking and maintaining the drivetrain is a simple process you can do at home. By following a routine of inspection, cleaning, and lubrication, you will ensure that the drivetrain works efficiently for longer and avoid unnecessary repairs.
Regardless of whether you use a mountain bike or a road bike, proper maintenance will ensure smooth gear changes, prevent annoying noises, and improve pedaling efficiency.
In this article, we explain how to perform a complete drivetrain inspection, what problems you can detect, and how often you should do it to keep your bike in optimal condition. 🚴♂️🔧
Check the drivetrain from home in 6 simple steps
Each step of the inspection will focus on a component or part of the drivetrain, so that the check is thorough. Below we explain how to check each component and how often you should do it based on usage.
Chain: after every ride
This is the drivetrain component that requires the most care and inspection. Its condition should be checked after every ride, especially if you cycle off-road, such as mountain biking or gravel. If it accumulates dust or mud, it must be cleaned. First with water and soap or a degreasing spray, then dried and re-lubricated, either with oil or wax lubricant.
An essential tool you should always have is a chain wear gauge
In addition to cleaning and lubricating it, you should check the chain's elongation. With use, the chain's links wear out and the chain stretches, increasing friction and wear between it and the teeth of the chainrings and cogs. That’s why it’s very important to get a chain checker and use it at least once a month to monitor its wear. If the 1% (1.0) tips of the checker fit completely into the link gap, you should replace the chain with a new one and also the cassette. In this video by Macario Llorente that we share, they explain in detail how to use this checker correctly:
Chainrings, cogs, and pulleys: once a month
The next step is to check the condition of the chainrings, cogs, and pulleys. Make sure the teeth aren’t dirty or collecting dust or traces of grease. If they are, it’s best to clean them thoroughly with water and soap or by applying a degreasing product. It’s advisable to check them at least every two weeks or once a month.
Derailleurs: once a month
One of the points that requires the most attention, since the correct shifting from one cog to another or from one chainring to another depends on them, are the derailleurs. First, check the rear derailleur. Make sure the pulley superior on the derailleur hanger is aligned with the smallest cog and also with the largest, to prevent the chain from coming off or getting sucked in. If it’s not aligned, you’ll need to tighten or loosen the H screw on the derailleur for the lower limit (smallest cog) until it’s in the correct position. The L screw, located next to the H, will align the pulley with the largest cog. At the same time, check that the derailleur hanger isn’t bent. If it is, it will be necessary to remove the rear derailleur and straighten it. In this case, it’s best to ask a mechanic for help, as they’ll have the necessary tools. For the front derailleur, alignment with the chainrings is done in the same way as the rear. By tightening or loosening the respective H and L screws, you’ll adjust the precision of the chainring shifts and prevent the chain from coming off. It’s also a good idea to lubricate the pivot points of both derailleurs with a drop of lubricant (preferably for dry conditions) every month or two.
Cranks: once a month
One of the most frequent causes of poor drivetrain performance, annoying noises, or creaks while pedaling, is crank looseness. To check that they’re properly tightened, you can pull them toward you perpendicular to the direction of travel. Crank manufacturers recommend preventive tightening every 200 km ridden. But to make sure you don’t forget, add this check to the monthly or bimonthly inspection we recommend for components like chainrings, cogs, or derailleurs.
Bottom bracket: once a year
As for the bottom bracket, it’s recommended to do an internal cleaning (bearings, bushings) and lubrication at least once a year. If you do mountain biking or after winter, external factors like water, mud, or dust can get inside the axle and damage it, making extra cleaning necessary.
Shifters and cables: once every two months
The penultimate step of the inspection is to check the condition of the shifters and gear cables. For the former, check that the levers move correctly on their axis and do not have any play. Also, make sure that with each movement it clicks and the cog and chainring change. If it doesn't click or change, you will need to open the shifter cover, apply spray degreaser, and re-lubricate the mechanism with liquid lubricant. Chain lubricant can work, but do not apply it excessively. This will allow the shifter pawl to be free of dirt and move correctly again. On the other hand, checking the condition of the gear cables and housings is very important. Do a check every two or three months of use, or after the winter or summer season. The presence of worn or cut housings will require replacing them with new ones. An unadjusted and imprecise gear change may be due to worn cables, which will need to be completely replaced.
Pedals: after each ride
Finally, don't forget to check the pedals, both the lubrication of their springs and engagement mechanism (if they are clipless) and their tightness to the crank arm. After each ride, or after washing the bike, you should apply a drop of lubricant to each pedal spring. Secondly, check that they are tightly fastened, as otherwise annoying noises may occur due to play. We recommend removing the pedals, greasing the threads of the crank arm and pedals with assembly grease, and reinstalling them every two months if you ride frequently.
Remember not to overtighten the pedals, as they self-tighten while pedaling and it will be very difficult to remove them at the next inspection
Common drivetrain failures and how to fix them
Below we list the most common problems that can arise if proper drivetrain maintenance is not performed:
Rusty chain
It's not very difficult for the chain to rust, and it can happen even if it's not worn or stretched. If you rode your bike on a rainy day and didn't clean or lubricate the chain after the ride, rust will start to appear on the surface. If rust appears on the chain, clean it thoroughly with a degreasing product. Some lubricant brands even have specific cleaners to remove rust. Let the product work for a few minutes and then scrub the surface of the chain with a fine wire brush. Then rinse with water, dry the chain with a cloth, and lubricate it again. If there is a lot of accumulated rust, you will need to replace the chain with a new one.
Misadjusted derailleur
It is one of the most common breakdowns, resulting from regular use of the bicycle. The shifter cable tends to loosen over time. Any impact to the derailleur or derailleur hanger will cause jerking or the chain to jump to another cog, or it may not shift at all when changing gears. To prevent this, you can adjust the shifter cable tension yourself using the cable tensioner, which is usually located at the cable connector with the shifter. On road bikes, it is typically placed at the height of the head tube. Turning the tensioner clockwise will loosen the cable so the cogs shift down more smoothly. On the other hand, to make the cogs shift up properly, you should turn the tensioner counterclockwise. However, cable tension is not the only reason for poor shifting performance. It may also be due to a bent derailleur hanger or because it is not properly aligned with the largest or smallest cog on the cassette. In this case, you will need to tighten or loosen the H and L screws on the derailleur, as we explained above.
Broken teeth
A somewhat more serious breakdown is the breakage of a tooth on a chainring or cog, caused by the impact of a stone, a fall, etc. This can cause skipping, chain drops, imprecise gear changes, etc. It will be necessary to replace the affected cog with one that has the same number of teeth. The same applies to the chainring. Do not delay its replacement, as otherwise the drivetrain will not work as it should and will accelerate the wear of the chain, cassette, and chainrings.