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I plan on riding my Merida Matts 40-D in mountains like these:
The temperatures are usually around -20 °C and I was wondering whether anything can break on my bike due to the freezing conditions. Is there anything I should take special care of before/after any such riding?
-20C is -4F, cold enough to be uncomfortable for humans, but not particularly cold for mechanical equipment. You will notice that lubricants get stiffer, but generally they warm up rapidly when you ride and the stiffness will be gone in a minute or two. Hydraulic fluids, et al, should be good to -35C or below, though they will stiffen before that, noticeably increasing the response time of the brakes.
Steel and aluminum do get more brittle at colder temps, but not to a noticeable degree above -50C or so. Plastics and composites, on the other hand, are a bit more unpredictable -- most plastics get noticeably more brittle below about -25C, though no doubt there is a wide variation depending on the specific materials involved.
You will notice that the tires get stiffer, and people have reported difficulty with the tires becoming rock hard and spinning on the rims at low temps (eg, -20F). Also, of course, rubber brake pads get harder, and rim brakes become much less effective.
There's really nothing in a bike that isn't in a car, and cars can handle -35 or -40C. And the places where you have trouble with cars is mostly the battery and fuel system, components you don't have on a bike.
I live in Yakutsk, Russia, where the temperature sometimes drops as low as -45 °C.
I don't think anything can break if all your parts are in good condition. But I think you shouldn't let your bike stay out in the cold for too long. I suspect the oil in the suspension fork can freeze, temporarily changing it into a rigid fork.
You will need ice tires if you plan to ride on ice, but not if you plan to ride only on snow. For snow riding, knobby tires are fine, even if the snow is hard as concrete.
DOT4 or DOT5 hydraulic fluid will surely be fine. Mineral oil also shouldn't freeze, but I have no experience with brakes with oil.
Don't forget: your tire and fork pressures should be a bit higher because of the low temperature.
And last, but not least, choose your clothing carefully. Especially your gloves and shoes. Layer your sweatshirts so that you can remove a layer after about twenty minutes of riding. A windbreaker is very helpful.
I expect you should have ice tires.
Your brakes aren't user-serviceable, are they: so I'd ask whoever maintains them, about e.g. whether you have the right, sufficiently new and well installed brake pads. I bought a similar bike (i.e. alu and disc brakes) in Toronto in February for commuting, with the LBS assuring me it would be road-worthy. You have front suspension though as well, which I don't.
Apparently hydraulic brake fluid should be OK to at least -30C.
Beware of having to try to change a tire in that cold.
At -20 at riding on hills it might be difficult to choose the right clothing.
Hey to everyone reading this 4+ years later.
I just wanted to add to what people are talking about forks and "Suspended's" mention of the freehub. I just want to add what I've learned from biking for the past 2 years, year round in Ann Arbor, MI.
Fork: To me the biggest thing is salt, but since this was about temps and on the slope I would agree that anything plastic can't be trusted under -10*C unless it was designed for the cold. The seals will contract and leave open gaps, and if it was meant to bend... well it won't. On the other hand, The RockShox Bluto are meant for such conditions, and even ones with lock out can at least prevent wear. Also, those who have mid range forks, and want to use the suspension, Lizzard skins stanchion boots will protect from dirt getting past the open seals.
Hubs: After heavy (and rather hard) use of my bike I fear that the clutch system has been damaged from the pawls not fully engaging fast enough after slight backpedals. I haven't rebuilt it yet, but I'm pretty sure that this is the case. If you use your bike when it gets -20*C you have to take into account that parts won't move that quickly for you.
Drivetrain: Same thing as with the hubs not moving, but this usually happens due to slush. I've had times where ice got onto my rear derailleur and it took a hard bump for it to free up. The font can be just as bad if ice builds up between the post and the cage, but you can knock that with your foot on the fly. Another worry is that ice can build up on the cassette and prevent the chain from meshing or even shifting to a particular cog. This will usually happen on the one you use the least and all of the sudden need the most.
Over all though, most bikes with the right tires can be used at low temps given that they are cleaned and lubed for the weather. Also, I would love to do more winter biking on snow pack vs. mostly clear (but slushy and salty) roads sometime.
Perhaps. There are two main areas of a bicycle prone to damage in truly cold temperatures.
The first is your freehub. When the grease in a freehub gets thicker, it can prevent the hub from full engagement. At best this means when you pedal forward, nothing happens. At worst, you can get partial engagement and chip/destroy the teeth inside your freehub, destroying it. Winterize your freehub or risk this type of damage.
The second is suspension. Most suspension is designed to dissipate heat and doesn't deal particularly well with the cold. Cheap elastomer suspension will often crack and disintegrate, leaving a springing non dampening system behind. Oil and air systems often have seals that can deform in the cold or crack, rendering the suspension non-functional for either the short term or permanently.
Most plastics, metals, and carbon fiber will work just fine down to -40C (-40F), which is colder than most people are willing to ride. No part on you bike is going to magically shatter because it gets too cold. Any lubricated part (your chain, hubs, steering, pedals, bottom bracket, derailleurs ) will work, but may work less well because the lubricants get stiff (or solid). Except for your freehub/freewheel (which can be completely destroyed) none of these other areas are likely to sustain damage. The lubricants will simply slow/freeze them and they won't work until they are warmed up.
Most suspension (depending on type) will stop working at some temperature. Some leaf sprung style systems will not, but most systems will freeze. Depending on the quality/specs of other parts (seals, tolerances, etc) some systems may be damaged by continuing to use them after they freeze, others will survive to work again when temperatures rise.
I commute on a bike and I have on numerous occasions ridden my bike when it's around -15 °C. I haven't really thought about the bike to be honest and have not seen any damage to it.
However, the wind chill effect can be quite problematic and I have often had to shift hands and have one of them inside the jacket to prevent freezing.
Good luck!
@unforgettableid at the beginning. :)
Jan 14, 2013 at 1:50