often carry a small vacuum bottle filled with coffee or hot chocolate.
(These are available at outdoor shops and coffee shops and practically
everywhere it seems) A flask covered in a sock fits a water bottle
cage nicely, although I usually also secure mine with a toe strap.
A hot drink can really take the chill away, and your friends will
be quite envious.
To avoid dealing with frozen water, I may use a Camelbak,
and keep the hose tucked inside my jacket when I'm not using it.
Camelbak now sells a little hose insulator, which I have found
very effective. Blowing air back into the tube also helps keep
the tube from freezing.
If my feet get too cold on a ride (or any part of me, for that
matter) I stop at a café or if none is handy I'll go for
a convenience store. Eating and drinking warm stuff works wonders.
I remove most of my outer layer clothing. I get my shoes off and
wiggle my toes to get the circulation going again. Unlike running
or x-c skiing, the feet don't get move around a lot in cycling.
It's important not to stay inside wearing all your warm clothes,
because the body will adjust and then you feel even colder when
going back outside. If riding in a hilly or mountainous area never
stop at the top for any more time than it takes to add another
layer. You will be sorry! Sweat from climbing will leave you cold
and wet, and then flying down a hill afterwards won't do a thing
to get you warm again. In may seem hard, but try to plan rest
stops at the bottom of a hill, so you can use the climbing to
warm back up!
And eat. You are burning a lot of calories to keep warm and you
will need fuel. My winter rides almost always have a café
as a destination. (Although, so do most of my summer rides!)