Hey guys, in the past my chain would come off my front sprocket from time to time. I merely put the chain back on the sprocket and continued using my bike. However, it seems like the chain rub against the sprocket rather intensely, cutting away at the sprocket. Over time rust formed.

Firstly, did rust form because the sprocket is of cheap quality?

Secondly, can I clean and repair it?

As you can tell, I'm a cycling newb. Thanks for your help in advanced!

The bolts/nuts that fasten the chainrings can be replaced and any bike shop should have a set.

From what I can tell from your picture, you cross-chain a lot, that is you often ride in the small chainring and the smallest cog and that causes the chain to rub against the inside of the big chainring. That's what did the damage and also caused the chain to come off frequently in the past. Replace the bolts and nuts and avoid that gear combination. You can get the same results in the big chainring and a larger cog.

Steel chainrings will rust where the chain wears through the plating, but it's of no concern, except cosmetically.

If you ride regularly you'll not see the rust because the chain is constantly polishing the chainring the same way passing trains keeps the tracks polished (you only see rust where the wheels don't touch). If you don't ride for a while the rust can become more pronounced, but here too it's of no concern because the chain will polish it within the first few miles.

I wasn't concerned about the rust on the big chainring's teeth but on the ring below the normal chain track. It seems the chain has rubbed it there quite frequently. Also the chainring bolts are pretty bad too.

I didn't write my post for you, it was to reassure the OP about his rust concerns. I don't know if the rust on the inner chainring faces is because they're rusty, or transfer form the chain or smaller rings (via the chain).

But you're right that the bolts are showing some rust also, and maybe the OP should give the crankset a shot of our old favorite WD-40. I wonder if he's doing lots of wet weather riding, or maybe storing it outside or in a damp place. If so, he'll need to protect steel parts with an occasional spray of WD-40 or similar (I prefer LPS-1, but it isn't as readily available).

WD40! It works miracles, haha

Thanks everyone for your help! I do have to store the bike outside; I live in a tiny apartment in Japan and the bike is outside my door. The only thing protecting it from the elements is a vinyl bike cover. It flops around in the wind and moisture blows in under it. Violent storms blow the whole cover off.

The bike is only a year old, so I'm surprised parts of it are rusting already.

Here's a pic of the whole bike:


I recently put on Nitto Campee racks; unfortunately, they are not compatible with my bike. This is the thread I created about this issue: https://www.bikeforums.net/showthread...1#post13982498

Nice bike. I had the same thoughts when I saw the pics. Lots of rust! If the bike must be outside and face the elements, a bit of diligence and alteration can suit its conditions better. Stainless steel cables, and fasteners, aluminum fasteners. Even titanium fasterners are available for chainring bolts. Waterproof marine grease, stainless steel bearing balls.
A good coat of wax for the frame. WD40 as mentioned. Re-using old inner tubes cut into sleeves to slide over areas to keep water out. All will keep it operating well and make maintenance time go smoothly.

Check out Boeshield T9.

Yeah, extra care needs to be taken for outdoor bikes, especially if you're close to the ocean. I'd start soaking those CR bolts with PB Blaster or something right away so that they can be loosened when you decide to change them.

I wax my bikes once a year and they live indoors with me, if I had outdoor bikes I'd likely wax once in spring and once in fall. I also spritz stem bolts, etc with WD-40 often, as they tend to collect water and rust.

I'd also look into treating your frame's interior with some Framesaver or similar.

I usually ignore chainring and cog rust.

Thanks everyone for your advice. Here are more pics of rust:

I usually use Pledge spray wax, which is actually silicon. If your bike is outside and used frequently you should spray and wipe it down once a week; it also makes it real shiny!