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I've left my winter road bike outside in a bike tent for about a month (winter, UK). I noticed that pretty much all links are stiff and the chain is slightly rusted, making it impossible to use. Some rust was also present on the cassette.

My question is, what caused this and how can I prevent this from happening again? The chain was cleaned with degreaser and lubed after my last ride, and the tent is pretty good (as in water doesn't get in).

4
  • By "bike tent" I presume its an unsealed cover over the bike that is tied off to itself? IE, without a floor ? A photo might help, but at the moment it sounds like a fancy tarpaulin over the bike.
    – Criggie
    Feb 24, 2022 at 18:32
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    It does have a floor. It's effectively like a normal tent but shaped to fit a couple of bikes
    – maupertius
    Feb 24, 2022 at 18:56
  • 7
    "how can I prevent this from happening again?" Keep it beside you in your bed when you're not riding it, and stare at it obsessively. Rust can't form while you are staring.
    – kloddant
    Feb 24, 2022 at 22:53
  • @kloddant My knife begs to differ. But I have a really high prescription so maybe that has something to do with it.
    – DKNguyen
    Feb 25, 2022 at 1:11

4 Answers 4

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Even though there may not have been direct contact with water, there is water in the air. In a tent, the constant cycle of heating and cooling through the day and night, and the relative differences in the temperature of the metal and the air can cause condensation to form on the metal and subsequent rust. This can happen to bicycles in a garage as well, but there is typically less variation in the ambient and relative temperatures due to higher insulation.

What I do if I am not going to be riding my bike for an extended period is:

  • Clean everything;
  • Lube the chain with a wet lube - this will attract dust but will repel water;
  • Use a spray lube to lightly coat the cassette and chain rings.

When bringing my bike out of storage, there is another cycle of cleaning to remove the heavier wet lube and replace it with my normal dry or wax lube.

13

As you know living in the UK, we are an island that is prone to high humidity and damp overcast weather. When left outside anything that is remotely damp (you cleaned your chain and its virtually impossible to get it properly dry in winter) will remain damp until spring. Something like a bike tent will have poor air flow and trap moisture inside making this situation worse.

This is one reason why the 'winter' bike is popular here in the UK - people don't want to expose their best bike to the elements.

A few options that I have found to work are:

  1. Keeping the bike inside where its warm and dry (I guess a temperature controlled garage would work here too).
  2. Using a large quantity of wet lube. Chain lube is not really supposed to coat the outer surface of the chain, but by using a large quantity of a heavy/wet lube you can create a protective layer. Note that this quickly turns into a black sticky mess and causes increased wear rate - but no rust.
  3. Rust proof chains - in recent years i've been using a single speed mountain bike with a rustproof chain. It works much better than I expected. I'm not sure if this type of chain is available for geared bikes.
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    Even a non-heated but built-in (so it gets a little bit of heat from the house) and insulated garage helps a lot
    – Chris H
    Feb 23, 2022 at 15:49
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    Unfortunately keeping it in a garage or the house is not an option for me. I'll try the wet lube option and also ride it more often 😊
    – maupertius
    Feb 23, 2022 at 15:53
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You don't say if you did anything to work the oil (wet lube) into the chain.

If you use 1 drop per roller you really need to spin the pedals quite a few times to spread the oil out, especially if you've just washed it. Between washing and oiling I try to get as much water out as possible by spinning the pedals and by dropping the back wheel onto the ground, but there's definitely still some in there.

For planned, prolonged winter storage, I'd clean and oil, then a day or so later wipe the chain down and oil again. Ideally it would get a short ride in the dry on non-salted roads in between.

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  • 2
    I normally spin backwards a few times and clean the oil off the following day (without re-applying). I should probably put more effort in drying the chain before applying the oil
    – maupertius
    Feb 23, 2022 at 15:56
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    The problem is you can't get it really dry. A couple of repeats of spinning and wiping with a dry cloth are about the best you'll do
    – Chris H
    Feb 23, 2022 at 15:59
  • Compressed air blasts can work to get water out. But canned air gets pricey and a compressor costs money.
    – DKNguyen
    Feb 25, 2022 at 1:17
  • Couldn't compressed air forcefully push dirt to places where it can be harmful? Of course, shouldn't be a problem after proper cleaning.
    – laolux
    Feb 25, 2022 at 7:20
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If your tent is reasonably tight then you might try to add some dehumidifying agent. Around where I live you can get those cheaply and they slowly absorb up to 500 ml from the ambient air. This might be enough to prevent condensation on your bike. The tighter and smaller the tent the better.

EDIT
The question arose whether the desiccant would be sufficient in damp UK winter. The answer is yes. One cubic meter of air contains about 8g of water when fully saturated at 8°C. Assuming rather spacious 5 m³ for the tent, the 500ml dehumidifying container would be able to remove the entire moisture from the air about 12 times. This number drops to about 3.5 when we put the bike into the tent at 30°C in fully saturated air. We should also keep in mind that desiccant will usually not remove all moisture from ambient air (and that is not required to prevent rust). So even with significant leakage in the tent one simple dehumidifying container capable of absorbing 500ml of water from the air should be sufficient.

EDIT2
If worried about too much ingress of fresh moisture into the bike tent, then one can easily check the filling of the desiccant after a week. After initial removal of most moisture (including water drops left on the bike) the ingress of fresh moisture through leaks of the bike tent should be fairly constant, so that extrapolation should be feasible.
Additional benefit of this method: It potentially protects all components susceptible to rust, not just the oiled chain and related components. I had screws on my handle bar starting to rust during the first rainy season (continued to ride the bike through the rain and not much option to dry it).

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  • 4
    Is that really enough to absorb significant amounts of moisture from a damp, dreary, UK winter? OP doesn't indicate how big the tent is, but even a small, bike-sized tent is a fairly large volume of space to attempt to dehumidify with a desiccant.
    – FreeMan
    Feb 24, 2022 at 14:12
  • Positioning the shelter somewhere that it is in sunlight during the day would be helpful. Presumes there is some sunlight though.
    – Criggie
    Feb 25, 2022 at 0:07
  • Volatile corrosion inhibitor might work better. But you might need two or three blocks depending on the tent size.
    – DKNguyen
    Feb 25, 2022 at 1:13
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    @Criggie Not really. The assumption is that the tent is sufficiently tight, so a change of temperature would not change the amount of water inside the tent. Plus, changing the temperature due to sunlight does not change the amount of water in the air anyways, it only changes the relative humidity. Lower relative humidity helps objects dry, but it won't remove moisture from the tent even if it is not sealed.
    – laolux
    Feb 25, 2022 at 1:50
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    It's probably this one from Halfords with a great big vent visible at the back to let vapour in as well as out. As well as the zip. My "daily" was worst case but you'd be changing the dessicant every few days due to vapour getting in, plus once as the bike dries out. I've used those disposable ones in a caravan (with all vents taped up) so I know how quickly they fill up in confined space.
    – Chris H
    Feb 25, 2022 at 10:10

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