Unfortunately, I've got the fine motor skill of an elephant. This in combination with wearing thick winter gloves, being tired during/after riding and everything being wet and slippery means that I drop bike lights a lot. Somehow, I think that I might not be the only person to have these struggles in winter, so what can I do to attach/detach/carry bike lights in winter without dropping them? — I can't leave them on because they will get stolen. The temperatures are often below -10°C, which means that taking my gloves off even for a few seconds is extremely painful and they go numb... and then my hands are even more useless than before.
For similar fine tasks, silk inner gloves are ideal. They are very thin but add a noticeable amount of warmth. Their real benefit comes when you remove the outer gloves and have essentially bare hand dexterity with some insulation. Then you just have to get your timing right to minimise the amount of time your outer gloves are off.
Some people use latex or nitrile gloves in a similar way but I find them too sweaty.
To add a bit of perspective to the glove liner/inner gloves answers:
I stopped spending much money on this kind of thing a long time ago because it isn't really necessary. If you have the budget and the shopping time, getting the best of everything is of course great (in this case, you probably want two, one backup). However, I live in Canada and like to cross country ski (and also ride my bike in the winter) and I use this arrangement in -20°C weather on frozen lakes, where there is no where to hide if 30-40 km/h winds spring up, you have hours to go, and you now cannot usefully expose bare hands for any length of time.
The first picture are cheap (~$2) synthetic stretch gloves that can be found almost anywhere. The thing to avoid here is anything with too much cotton, since it absorbs sweat and looses its insulation value when wet. These breath well and even soaked can be rung out and remain better than nothing. They look like kid size gloves but stretch.
The second picture is them under another pair of relatively light, non-waterproof, thinsulate gloves, to illustrate they're fine under anything. The outer layer comes on and off easily. I can actually pack both layers into a snowmobile mitt, although that is a bit excessive. If you are sweating, having some free play between layers is better.
The third picture are work gloves, ~$5. These are more windproof but not as snug, so don't fit as well under other things -- but note that you want loose, and not tight, here anyway, because if it all packs too tight it will hamper your circulation. Those work fine for me under, e.g., water resistant ski gloves that are bulkier than the ones in the center picture. These are also something you could keep warm and dry in a pocket and only take out when you need to work on the bike. The black leather-esque material grips well.
So again, if you have access to a good outdoor store and want to spend $20 on proper inner gloves, you'll have a better product. Personally, I'd rather have two pairs of cheap ones though. They're light and ball up to egg size, so it is easy to keep the extra pair warm and dry somewhere inside your jacket.
I highly recommend a set of poagies, which will likely be far warmer than your gloves to start with. You can throw chemical warmers in them to really make them like an oven. At that point a very thin set of gloves (like regular summer full fingers) that still offer some protection can be used quite effectively for short bursts outside your poagies. For one to have immediate problems when removing gloves in the cold, it suggests a circulatory issue, or that your hands were not reasonably warm to start will. Either way a good set of poagies will put you in a better starting place.
I would also look into the headlamp idea. The main disadvantage to a headlamp is riding with one while snowing. The rest of the time they work as well or better than most bike mounted lights and require no extra effort when you leave your bike. I actually wear my red blinky (as well as sometimes a total of three) attached to the headband of my headlamp and call it my "crown of dorkdom". It looks dumb, but it can't be missed. It also means I don't have to mess around with my blinkies in the cold. When it gets really cold, plastic gets brittle, and dealing with cold plastic as little as possible is the best way to extend it's life.
First idea is to attach some stiff cord that you will first string over your handlebar or just lamp mounting point. Then you can try as much as you want to put your light on. On drop it will hang on the cord. It has to be not too long.
Third idea is to use Headlamp and taillamp integrated in your helmet. You can prepare it when you're in warm place. I think it should be just an addition to regular lights, but this is kind of solution for you. Note: assure that regulations in your area allows you to use on-body lamps.
Last idea, in my opinion the best one, but also the most revolutionary - move to hub dynamo powered, permanently mounted lamps.
Firstly, you can actually take your gloves off for a few seconds at -10. Even at -20, if you are not in the wind. Make sure your hands and gloves are warmed up before (and for that, make sure the rest of your body is properly covered and warm. When you stop right after a ride it should be the case), take off one glove, do what you have to do, put it on again.
It is not pleasurable, it might hurt a bit, but if you really need those fine motor skills, you can do it. Just make sure to put your hand back in the glove before you stop feeling you fingers.
Now, I understand that you would not like to do that everyday, or several times per day. So:
- Store your bike inside (in a garage, for example), if possible. Even if you still need to remove the lights, you can now do it in a warm place
- Use a headlamp, as suggested by krzyski, but use one that mounts on your helmet. More than likely you have a helmet and a face mask that covers your face, and no room to fit a headlamp on your forehead (I know I don't).
- Use a lamp that cannot be stolen easily (screwed on with a special screwdriver). Thieves may think twice about stealing a bike lamp if it involves fine motor skills and special tools
- Use 2 pairs of gloves BUT make sure the liner pair is wind resistant and warm, and have some level of water resistance if it snows. (not a very thin silk glove) You'll get less motor skills, but more that with those big gloves of course.
- Use a cheap lamp that you don't mind getting stolen too much. It depends on how often it gets stolen, of course, but make the calculations. Always carry a spare.
An alternative to the included light mount is to affix a complementary pair of strong magnets to the light and to the mount point on your bike. I did this a while back using Sugru and some coin-shaped neodymium magnets bought off Amazon, to let me mount a rear light easily on my helmet. It is so simple to attach that I can do so while riding (with the helmet on), if need be.
You don't need the Sugru necessarily -- any strong thick adhesive should work -- although it is probably the easiest option on handlebars because it stays put so well once you've molded it.
The magnets should be as strong as possible. I have never had the light fall off my helmet unless I actually whacked it while putting my bag on. However, I have seen another light mounted to my bars shift occasionally if I hit a bump.
Magnetic mounts make removing lights as simple as grabbing and pulling, and attaching them an absolute breeze. Holding on would be all that was left to worry about.