The chain on my road bike has about 1k miles on it. It formed a little rust after a couple rainy rides at the end of the season when I stopped riding.

I am wondering if I should try and clean the rust off, or just put on a new one? And if cleaning is the solution... what is the best way to remove the rust?

Also, compared to a new chain, there is only 1-2 mm stretch on the rusty chain. How much stretch warrants the need for it to be replaced?

Change your chain once 12 links has stretched between 1/16" and 1/8" past 12": https://sheldonbrown.com/chains.html#wear

A little rust on the chain isn't irreparable. I find Tri Flo gets rid of a lot of it. I'm sure others have better ideas.

A little rust on the outside of the chain will make no difference at all, except to aesthetics. I'd just ride it until it wears out, and not think twice about it.

Surface rust isn't dangerous. Clean it off however you want. Degreaser or WD40 maybe. Then be sure to lube it after that dries.

If the surface is rusty its a good possibility that the internals aren't much better. Rust is a symptom of improper lubrication and exposure to the elements. It'll be systemic.

Just do a complete WD-40 clean, (or better yet citrus degreaser) let it dry over night, and re lube. I use a hard bristle toothbrush for rust. I replace my chain after 10,000 miles now. Why? because the chain wears with the cassette and chain rings. Replacing any one of these changes everything. If I change one thing, I have to change it all. So I run it until its dead, or until I want 10 speed

No sense in trying to get rid of the rust, just lube and ride...and lube more frequently next time.

Unless it's real bad there's no need to replace your chain. You'll be surprised at what a shot of Tri Flo or something similar followed by pulling your chain through a clean rag will do. Two or three minutes is all that it takes.

+1

ok, thanks for all the replies,


I should be able to remove most of it pretty easily. I plan to wipe it down with wd40, soak in mineral spirits, and then relube. I think that will do the trick.

And then some.