IAmNumberHero

Hi everyone,

Some background info
I bought a second-hand used hybrid bike. Brand of the bike is Nakamura, model is Lyon (seller misleadingly referred the model as the Nakamura's Alsace Men hybrid bike from Sports Experts). He originally listed at 170$ CAD. But I struck the deal down to 140$ CAD because when I inspected the bike, I saw that essentially the whole drivetrain of the bike is rusted (hence the discount). In addition to rusted drivetrain, many fasteners of the bike were worn or oxidized too.

Retail price of this kind of amateur hybrid bike is around 400$ CAD sales tax excluded (based on Sports Experts website). Although the drivetrain is covered with a layer of rust, the ride seems smooth with gears shifting well across different speeds. The seller told me the reason for the drivetrain's oxidation is due to him storing the bike unused at home for more than a year. Also, he bought this bike three years ago. Even then, I found it very suspicious and should have walked away from the offer instead. I am wondering how the heck did the drivetrain rusted so much? Even my road bike that were stored over the years still have its drivetrain perfectly clean and rust-free.

Restoration of drivetrain suggestions and outcomes
Now that he refuses return the bike, I am wondering how effectively would I be able to restore the bike's drivetrain. Should I replace any parts of the driving system (cassettes, chain rings)? If I restore the drivetrain, what options would be the best (using evaporust, cleaning it with aluminum foil dumped with vinegar/coke or another method)? I am not a bike mechanics, but will try to learn from any of you if you have useful answers and suggestions to my questions. Thank you! Also, let me know if the deal I made for this bike was great or not. What would you have done instead for the deal?

It seems I cannot post the pictures of the bike and drivetrain because I am a newbie to this forum. Let me know how I can bypass the restriction and share the pictures to you.

Crankycrank

Try just brushing off as much surface rust as you can off the chain without spending too much time doing so. Oil the chain with the lube of your choice and see if it works OK. New chains for 7 speeds (the number of rear sprockets on your bike) are cheap, $10 U.S. for a decent quality KMC, SRAM or Shimano chain so may not be worth too much effort to save the rusted one.

JoeTBM 

We get in a lot of rusted bikes in our work.

If the chain doesn't have hard frozen links and is not worn to the point of being "stretched" we will attempt to removed much of the surface rust by running the drivetrain and using a stiff wire brush on the rear cogs and chain, blow it clean using a compressed air gun and the generously lube it up and dry it with a clean rag while running the drivetrain slowly.

wear disposable gloves and safety glasses

Litespud

if the drivetrain rolls and shifts smoothly, it can’t be that rusted. I say put some lube on it and ride it

Jerseyroam

One word... evaporust
works great on removing rust.

Iride01 

Does the bike function correctly?

If so, just wipe some lube on it and ride it. For certain keep vinegar and any other acids and caustics away from it.

Papa Tom

How do you guys feel about using Coca Cola to remove rust? I ran a bicycle recycling program in the late 90's/early 2000's with a very limited budget. The local supermarket donated cases of cola for our volunteers to drink, but when I read somewhere that it is an effective rust remover, we started using it on handlebars and other rusted parts. It was very effective, although I sometimes had trouble keeping ants off the bikes once they were shiny and new-looking again!

Anyway, what about Coca Cola for chains and cassettes? Just asking...

sch

Most commonly available acids will remove rust. Cola is a dilute phosphoric acid solution and may create some iron phosphate
but this is not likely to last in chain use. Main problem is you must thoroughly rinse off the chain and even then some mechanical
pre soak rust removal may be needed. Once chain is rinsed and dried, preferably as we are going into cooler weather, with a
little heat it should be lubed. If not lubed or rapidly dried, or rinsed completely flash rust will occur. It helps (a lot) to completely
degrease/clean it before the acid dip. Vinegar works fine. Hydrochloric ditto but is nasty stuff and flash rust post dip is worse with this stuff.
Citric and oxalic acids also work as derusters. Evaporust is a very good deruster but $ unless you have a lot of stuff to derust compared to
white vinegar or the cheap diet colas at under $1 for 2 liters.
FWIW a mildly rusted chain + lube makes a nice gritty abrasive mix which will accelerate chain wear.

rydabent

The true and simple answer is that rusty chains and cassettes need to be changed. Oil and rust is a great cutting compound.

55murray

I would replace the chain, the rusty cassette would not bother me much, just hose it down with wd40 to darken it and keep it from rusting further.

Iride01 

Rusty chains that still function aren't going to be that much worse for wear than a chain that is not rusty. Most of it is outside where it's not going to do much more than what the dust and grit that get kicked up into your chain and cassette do already.

The most that needs to be done is simply knock the rust off with a wire brush and then lube it up. If it wears quicker, why care, just run it till it shows the amount of wear that you normally replace your chain at. If it lasts longer than today, you got more use out of it.

Using acids or caustics on it are going to probably do more harm than help, because the rusty surfaces you see on a chain aren't the places a chain wears. And leaving it in something long enough to look like it's done something to the much more rusty outside is going to do more harm to the wear surfaces of the chain that you can't see. And then, you have to be certain you get all that acid or caustic out of the wear surfaces which is a guess since you again, can't see them.

So if anyone has statistics on how long a rusty chain lasts over a clean chain, let us know. My kids road bikes with rusty chains for many years. I never replaced a chain on their bikes.

woodcraft

+1

Gresp15C

In my view a bit of surface rust is purely a cosmetic issue. It will be quickly worn off the contacting surfaces, and basically flushed away, especially if you use a very lightweight chain lube. I'll bet after a few hundred miles, the surfaces that matter are all shiny again.

woodcraft

When it gets to this point, 'tho, it might need more than oil.

Gresp15C

Here's the chain on my winter bike. I assembled the bike last summer, lubed the chain, and left it in the back yard under a bush. When the salt trucks came through, I got it out, and rode it daily through the winter on heavily salted streets. When my boss sent everybody home in early March, I parked it back under the bush and left it there. Last week I decided to get it back out and re-paint the chain guard, so here it is in my garage. In exactly this condition, the chain runs perfectly smoothly, no stuck links.

What's my point? It's twofold. First, a little bit of surface rust is de rigeur for a bike that's used under typical conditions and not just a fair weather friend. Second, bikes are a lot less delicate than we tend to assume. Maybe getting used to a bit of rust is a step towards involving our bikes in more of our daily lives. We can't shelter ourselves from the outdoors whenever the weather turns.

JoeTBM 

Agreed, time for the 3' bolt cutters and deposit it into the scrap iron bucket

SurferRosa

Rusty chains are garbage. Life's too short.

zacster

While it is easy to say "just replace the chain, they're cheap enough" a lot of these rusty chains probably don't have anywhere near the usage that us forum members have on ours. Remember that a very large percentage of bikes are bought and never used, left out in the elements, taken into town once or twice, etc... How many family groups have you seen on the trail where the 3 miles from end to end is considered an "epic" ride for the little ones, and the parents too. Just lube it up and go.

IAmNumberHero

Thanks to you all for sharing your advices on the issue! I will take them into consideration and see how I will treat the rust on my bike.

Bill Kapaun

I've got bad eyes and I can see the chain isn't totally straight on the lower "span". The little ups & downs between some links.

Gresp15C

True. That would give me pause if the bike had a derailleur. In this case, a bit of additional lube will straighten it out.

Ironfish653

For an “amateur hybrid bike” that has a slightly rusty chain, but otherwise runs smoothly, I like to use ATF (automatic transmission fluid) to recondition it. Anywhere from a couple hours to overnight usually does the trick.
It’s a little thicker than the stuff I use on my ‘fast’ bikes, but it stays with the metal longer.
I use it on the kids’ bikes, and any lower cost ‘flip’ bikes I might be working on.

zacster

Just put some lube on it and ride it around the block and it'll be fine. A lot of lube but then wipe it down with a rag.

sovende

I think you did OK, price wise, in spite of the rusty chain (and other rusty bits). If after the rust treatment of the chain (as suggested by several), there are still some "frozen" links, then I would replace the chain. Rust on the cogs is more of an appearance issue and doesn't affect function too much. The "Virgo" in me says take that freewheel (or cassette) off and soak it in some sort of anti-rust solution. If my OCD was totally out of control (I'm OK for now ), I'd consider disassembly and intense de-rusting. To be sure, I'd do a serious "fluff & buff" and have a serious look at all ferrous components. The disuse, abuse and/or general lack of care that resulted in the clearly visible chain and cog rust, likely resulted in rust elsewhere. Pretty easy to remedy, you just have to,do it!

Amt0571

Ehm.... NO. I've ridden my bikes under the rain lots of times, and they never rusted like that. Well, they never rusted at all. Mainly because I care for my bikes. It's as easy as drying and lubing them at the end of the day.

If you ride a lot under harsh conditions, it's also a good idea to inspect bearings regularly. Water gets everywhere and bearings ARE DELICATE, especially if they're packed with water.