When to replace your drivetrain

After you buy your bike you can’t just forget about it and still expect it to run well for the next 15 years.  Bikes are like cars in the sense that you have to continuously service them, especially if you want to get the full the life out of your bike.  The parts that wear out fastest are your chain, cassette, and chainrings, so these are the ones you need to keep a close eye on.

Generally speaking, your drivetrain refers to the parts of the bike which function to make the bike ‘ride,’ the parts which generate its propulsion.  The first part of your drivetrain to go is always your chain, simply because it is subject to the most mechanical stress and therefore wears out the fastest.  You can slow this down by regularly cleaning and lubricating your chain, but you can’t prevent it.  However, by regularly replacing your chain, you can save money in the long run.  Cassettes and chainrings also wear out, but at a much slower rate.  Ideally, you should get two full chains per cassette, and two cassettes per set of chainrings, depending on how well you clean your drivetrain, how much you cross chain, and most importantly, how regularly you replace your chain.


A standard chain checker, on a brand new chain.  On a worn chain, the tool will sit level on the chain.

If you’re riding with a worn chain, this wears down your cassette and chain rings much faster than the normal rate, so here’s how to know if your chain is cactus.  The first telltale sign is that your gears are skipping, or your derailleur isn’t shifting well, even after you clean it.  If you notice this happening, put your chain in the big dog at the front and try to pull the chain away from the ring.  If the chain is so stretched that you can nearly see a whole tooth of the ring, it’s time to replace your chain.  For a more precise measure, get yourself a chain checker.  Most will have a warning indicator that tells you you’re getting low, and a ‘change now’ indicator.

Providing you take good care of your chain, it should last about 3000kms, and as mentioned, you should get about two chains per cassette.  However, if your chain is slipping even after you’ve put on a new chain, that’s an indicator that you may need a new cassette.  If you want to know for sure, pull your rear brake on and push on your pedals – if the the chain rides up on the cassette teeth, it’s time for a new cassette.

If you’re riding with a worn chain, this wears down your cassette and chain rings much faster than the normal rate.

Last to wear out are your chain rings, and as above, you should get two cassettes to a chain ring.  If you notice that the teeth on your chain rings start to hook over and look like shark teeth, it’s time for new rings.

The earlier you notice your parts are worn out the better, so be sure to keep a close eye on your drivetrain.  If you want to know how to clean your chain to get the most life out of it, here’s a link to our recommendation for cleaning your drivetrain.

Categories: Maintenance, Riding Tips

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