I failed to replace my chain at the proper interval. Will I have to replace my whole drivetrain?

Question

My bicycle is a 2012 Specialized Secteur. It has 6000 miles (10000 km), and I have never replaced the chain.
I recently began noticing that the chain always seems out of alignment with the rear cassette, no matter how finely I adjust the rear derailleur. This feeling only occurs in certain gears (the ones I tend to use the most). In these gears, the chain clicks softly. It is almost like it wants to skip off of the current cassette gear onto another. The feeling is similar to when the rear derailleur needs an adjustment because it is trying to set the chain between two gears on the cassette.
I know that when a chain is worn, it will "jump" gears because it has enough free play to prevent a proper mesh with the gears of the drivetrain. That led me to research when a chain should be replaced. To my horror, I realized that I had ridden the bike three times the recommended replacement interval. I have regularly cleaned the chain throughout its life and kept it lubricated.
I know that I must replace the chain, but before I do, I would like to know if it is possible that the rest of my drivetrain is salvageable. Should I replace the chain and see if the problem goes away? If not, should I follow with replacing the rear cassette, then if that also fails to fix the problem, the front chainrings? Or, is it possible that this symptom that I am experiencing is not related to the chain's wear at all?

Criggie · Accepted Answer

Yes - after that mileage you will need both a new chain and new cassette.
A new chain on the old cassette will not mesh right, and accelerate wear on the new chain.
Depending how much chain elongation has accrued, you may need new chainrings too.  They wear slower because more teeth are engaged in the chain.  Look at the chainring and see if the scallops are asymmetric, which is worn.  You can also wrap the new chain around the teeth firmly, and look for gaps between chain and chainring.
There's also a chance you may need new jockey wheels in the derailleur, though these are only guides and not load bearing so tend to last a very long time.
It would not hurt to replace the gear cables too - they're a relatively minor cost, and a complete fresh set will make it all feel even better.   You should also deep-clean both derailleurs, and lube the shifters while its all apart.

ryan · Answer

most likely yes because a worn down chain could wear down a cassette
hold the brake down and try move the crank if the chain is climbing up the teeth on the cassette you need a new chain and new cassette maybe even the chainring

Kev Peard · Answer

The other posters are probably right. But, if you haven't money to burn, I would replace the chain first and see how it goes. You say you keep it clean and well lubed so damage to the front chainrings are less likely and unless you seldom change gear, the cassette may be good enough to last another chain. Have a look at the teeth to see if they look like they are starting to lean forward, if so they are shot. If the chainrings and cassette are badly worn, don't use the new chain until they are ready to be replaced together, it will accelerate the new chain wear.

Answered by Kev Peard on May 16, 2021

Mohair · Answer

The time to replace a chain is when it needs replacing, not at some predetermined interval. Take it to the bike shop and have them use their chain stretch tool. From the symptoms you describe, you probably need a new one.
I have never replaced a chain at 2,000 miles, and in younger days, I was I was doing 10,000 miles a year on pretty expensive equipment that I maintained religiously. Road or mountain, with plenty of wet and muddy conditions, I'd get 5-6,000 miles out of chain. Maybe chains were better back in the late 1990s and early 2000s?
The truth is, your chain will start stretching from day one, and wear is unavoidable. For me, the real measure for chain replacement is performance. If you are no longer getting clean shifts, take it to a shop and get them to measure it. A minor cable adjustment might take care of it. But if you are getting excessive chain drift and skipping, then you've probably run your chain past its limits, and that will be unnecessary wear.
I think whoever came up with the 2,000 mile thing is just looking to sell chains!

Dave Brunker · Answer

Bike chains don't have to be replaced at a time interval.  You can ride a bike on a airport runway for years and never wear out the chain or you can ride up a mountain every day and have to chain wear out in weeks.  As the chain wears big parts get smaller and the small holes that hold them in place get bigger.  The chain "stretches".  It's not stretching like a rubber band, but it does get longer.  The rollers start to smash into the gear teeth and wear them down.  They go from squared off to pointy.  Some people nickname them "shark teeth".
Looking at the picture, your cassette looks fine.  Like Mohair said, go to a bike shop and have them check it. You can also get a go/no-go chain tool from Park that isn't too expensive and will let you know if you're chain is worn.  Just make sure you know how to measure it right.  I'm sure there are online instructional videos and websites that can tell you for free.

I failed to replace my chain at the proper interval. Will I have to replace my whole drivetrain?

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