Storing a Bike Outside in a Nordic Winter: Snow, Ice and Salt
A bike that lives outside through a Nordic winter has a harder life than one parked outside in Bristol or Berlin. The problem is rarely the cold. It is the cycle of snow, thaw, road salt and refreezing that works its way into every bearing and cable between November and March. Here is how to get a bike through it without a garage, and what a cover does and does not do.
What winter actually does to a bike
Cold on its own does very little. Steel, aluminium and rubber are fine at minus twenty. Grease thickens and tyres go hard, but nothing is damaged.
Snow that melts and refreezes does a lot. Snow lands on the saddle, bars and chain, melts a little in the afternoon sun or when the bike is wheeled indoors, runs into the chain links, the cable housings and the headset, and freezes there overnight. Repeat that fifty times and you have seized cables, a stiff chain and rust in places you cannot see.
Road salt and grit are the worst of it. Salt dissolved in slush is far more corrosive than rain. It gets thrown up by passing traffic onto a parked bike and sits there until something washes it off. Chains, cassettes, bolt heads and the contacts on an e-bike all suffer.
Sun matters more than people expect. Low winter sun reflected off snow is hard on tyres, saddles and grips over a whole season.
1. Keep snow and salt off the bike
A waterproof, seam-sealed bike cover stops snow settling on the bike and keeps salty spray off the drivetrain. It is the single most effective thing you can do for a bike parked outside in winter, and it costs less than one replacement chain and cassette. Brush snow off the cover before you lift it, rather than letting it slide down into the bike.
2. Choose a cover that lets air move
A sealed plastic sheet or tarpaulin traps moisture against the bike and causes the very rust it was meant to prevent. A fitted cover that is elasticated at the wheels and open at the bottom lets air circulate while keeping snow and spray off. BikeParka covers are made of breathable ripstop polyester with taped seams, shaped with toggle adjusters rather than sealed to the ground. Bicycling noted the same thing in its review: "Unlike many designs, the Bike Parka is breathable, which helps reduce corrosion and mildew."
3. Get it off the ground and out of the wind
Slush and meltwater pool at ground level. A wall hook, a stand or even a paving slab keeps the tyres and the lower frame out of it. Park against a wall or under an eave, out of the prevailing wind, so drifting snow does not pile against one side of the cover.
4. Lock the cover as well as the bike
Winter wind takes covers. Tighten the toggles every time, and if your cover has lock-through openings, put the lock through them. The URBAN, Longtail, Longtail WS and Cargo have them. The STASH and XL / MTB do not, so lock the bike as normal and cinch the cover tightly over it.
5. Keep the chain oiled, and rinse salt off when you can
A cover keeps most salt off, but the drivetrain still picks it up while riding. Wipe and re-oil the chain after a slushy week. When the temperature allows, rinse the frame and drivetrain with plain water to get the salt off. Do not use detergent on the cover itself. If it needs cleaning, rinse it and let it dry fully before it goes back on.
6. E-bikes: the battery comes inside
The cover protects the motor, display and contacts from snow and salt, but lithium batteries lose capacity below freezing and should not be charged when cold. Take the battery indoors and charge it at room temperature. There is more on this in leaving an e-bike outside.
Which cover for winter?
The same one as for the rest of the year. The STASH or URBAN fits road, hybrid and city bikes with handlebars up to 63 cm; the XL / MTB fits mountain bikes, wide bars and most larger e-bikes; longtails take the Longtail or Longtail WS; front-loader cargo bikes take the Cargo. Studded winter tyres and mudguards do not change the fit. Find Your Fit lists over 1,000 bike models.
Winter storage: common questions
Can you leave a bike outside all winter?
Yes, if you keep snow and salt off it with a cover, keep the chain oiled and bring an e-bike battery indoors. The bikes that come out of winter badly are the uncovered ones.
Will a bike cover freeze to the bike?
A fitted cover that sheds snow and lets air move underneath does not freeze to the bike. Ice forms when meltwater is trapped between two surfaces, which is what happens under a plastic sheet lying directly on wet metal.
Does a bike rust under a cover in winter?
Not if the bike was reasonably dry when covered and the cover is breathable. Rust under a cover almost always means water was sealed in. There is more on this in do bike covers cause rust?
Should I take the cover off to let the bike dry?
If the bike went under soaking wet, give it a few minutes to drip first. Otherwise leave the cover on. A breathable cover dries the bike faster than leaving it exposed to the next snowfall.
What about a bike that is not ridden all winter?
Clean it, oil the chain, pump the tyres and cover it. Check it once a month. Indoors is better if you have the space; outdoors under a cover is fine if you do not.
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