I live in the Yukon where typically it starts to freeze and begins to snow in October, then progressively gets colder and colder. This weather often lasts until mid-March and then begins to let up in April.
Since I commute to and from work most days on my fat bike, I spend a lot of time outside in the cold grinding away against the elements. We thankfully don't have salt on the roads, but the combination of snow, ice, gravel, rocks, sand, dirt and frigid temperatures are tough on a bicycle's drivetrain.
Over the years I've tried many different chain lubes – dry, wet, light, heavy, wax, oil and/or synthetic - but have never found one that truly worked well.
Heavy, wet chain lubes get even heavier and extra gummy in the cold. Same with waxes. Light, dry chain lubes can't take the abuse and wear off too quickly. I think what may work well would be a synthetic, semi-dry, semi-thick lube.
When I saw bottles of the Muc-Off -50°C chain lube on my local bike shop's shelf, I was suspicious. It smelled like a marketing gimmick, but I instantly wanted to try it on my fat bike. Muc-Off already makes my favourite chain lubes for both on and off-road in other seasons, so I trust the brand.
Turns out this stuff actually works as sold.
The coldest weather I've ridden my fat bike in this year has been -28°C, but the Muc-Off -50°C chain lube went on easily (I think it also smells pretty good) and stayed on at that temperature. I now only have to lube my chain about once a week and it doesn't make a mess or get gummy in the cold.
If you ride a fat bike in winter – or for that matter, any bicycle in the cold – try Muc-Off -50°C chain lube. It simply works.