When you buy a new chain, it comes lubricated with a factory-installed grease-type lubricant. This lubricant is similar to hot wax. (Reliable sources — including Sheldon Brown, Shimano, and others — seem to agree that you should not deliberately remove this factory lube.)

Imagine that you own a low-end 21-speed bicycle, which you bought second-hand. You use it for commuting in a big city — in warm, dry weather only. You've bought and installed a brand-new chain. If you never clean or lubricate your chain, what will happen?

(In my experience, the bike seems to keep working for numerous miles without squeaking. But I wonder what's really going on behind the scenes, and what the results might be.)

Please assume that you do replace the chain whenever it's stretched by more than 0.5% (1/16"), and that you complete most other recommended bike maintenance on schedule. The only maintenance you skip is chain cleaning and lubrication.

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    Squeaking/noise is just one symptom. Friction is a loss of energy that could otherwise drive you forward. Lubes decrease friction, therefore a well lubed chain is faster than a poorly lubed or dry chain.
    – Criggie
    Commented Jan 3, 2018 at 12:44
  • Not sure if this counts in the 'what will happen' .... My sister -in-law had her squeaky chain squirted with water from my drink bottle on ride last weekend.... a 'small' amount got on her (accidentally, honestly it was an accident...) -
    – mattnz
    Commented Jan 3, 2018 at 19:40
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    Basically, if you don't service it regularly it will wear out faster, and cause more wear on the cogs -- just like a "used" chain (which it is, after 200 miles or so). Commented Jan 4, 2018 at 2:13
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    Do you mean a conventional derailleur system or a single cog system (single speed or IGH) And does your bike have a chainguard? Is it partial or fully enclosed?
    – Criggie
    Commented Jan 15, 2018 at 19:12
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    @Criggie: A conventional derailleur bike. I know it's possible to install a chain guard on a derailleur bike (see here), and I know this would likely help, but I haven't bothered installing one. Commented Jan 15, 2018 at 19:34

2 Answers 2

  1. Higher friction (comparing to properly lubricated chain) between chain pin and inner plate will make groove in pin surface faster, resulting in chain prolongation (a.k.a. chain "stretching").

  2. Non-lubricated chain will be more exposed to corrosion.

  3. Higher friction between the chain rollers and the chainrings will make the chainrings wear down faster.

  4. Higher friction between all chain components will add avoidable resistance.

  5. People on the street will look at you with embarrassment and compassion because of noise.

  • 2
    Higher quality chains are typically nickel plated which makes them very corrosion resistance even without lube.
    – Rider_X
    Commented Jan 3, 2018 at 17:21
  • I think your points are correct, but they all assume the factory lubrication wears off. Interesting would be to know the mechanism behind that since the OP asks what goes on behind the scenes. The wax doesn't just fall off the chain in large chunks, right? Does it mean it gets ground into finer particles which eventually do fall off?
    – stijn
    Commented Jan 3, 2018 at 19:05
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    Oh the look of daggers for riding a bike that makes noise! Its horrible to be on the receiving end of that stare and glare!
    – Criggie
    Commented Jan 4, 2018 at 8:13
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    @Rider_X right, but OP has low-end bicycle, which will probably get low - to -middle end chain without superb coating.
    – krzyski
    Commented Jan 4, 2018 at 9:31
  • @krzyski - I was simply pointing out an implicit assumption. I would simply caveat the statement with “lower end chains.” The OP seems to be interested in a general discussion as much as cost savings.
    – Rider_X
    Commented Jan 4, 2018 at 18:18

What will happen is exponential damage.

At some point of time, probably after 1000 km or so (if never riding in rain; if riding in rain this will happen sooner), the chain starts to squeak a bit. This is the point where you should clean and lubricate your chain.

But if you don't do that, the chain will squeak more and more, and the wear becomes worse and worse.

I once had a chain that squeaked a bit but was about halfway in its wear life. I postponed lubrication for about 200 km. The squeak became rapidly worse and the chain was already past the 0.5% wear mark after that. So in about 200 km I destroyed half of the wear life of a chain. So we can conclude that a squeaking chain will fully wear in 400 km. (In contrast, I get 4500 km wear life from properly maintained chains.)

You should replace the chain at 0.5% wear mark, but let's suppose you don't do that. Then first your cassette sprockets will become worn in a manner that they no longer work in a new chain. Later this will happen to your chainrings too.

At some point of time, the chain is even at damage of snapping, in the worst possible moment, when climbing a steep uphill pedaling standing.

When you try to repair your bike after that, you will discover that buying just a new chain isn't enough. You need to replace your cassette and all of your chainrings. If you're still alive, that is. If the chain snaps when riding uphill when a car is overtaking you, you could be already killed at this point!

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