[INDENT] Black Ice, that thin layer of ice covering roads, perhaps only in shadowed area, can be one of the most insidious winter risks to deal with. You can be riding along on bare pavement one minute and sliding down the road the next instant.
Black Ice is called Black, because it takes on the color of the underlying pavement. It is very thin, and often gives the impression of having some surface irregularity, and therefore appears to supply some traction. These looks can be deceiving, because as soon as you apply brakes (or make significant turning movements) you start to slide.
[/INDENT] **Turns**
[INDENT] Turns on Black Ice are best accomplished by keeping the bike as upright as possible. This may involve offsetting your upper body to the side (toward the direction you want to turn) while at the same time keeping the bike upright.
The principal reason to keep the bike upright is NOT to keep more of your tire tread (or studs) in contact with the road, but more simply, that a leaning bike necessarily puts lateral forces on the tire at the contact patch. The contact patch (where the rubber meets the ice) is that preciously small area providing all the traction. Black Ice frequently does not supply enough traction to counteract this lateral force, the tire slips out from under you, and down you go.
Turns with the bike mostly vertical also imply slow turns. That, more than anything is the name of the game.
[/INDENT] **Braking**
[INDENT] Braking on black ice will cause a slight melting of the surface layer of the ice, producing a very thin layer of water. Water on ice is a lot more slippery than just ice. ([See: How Slippery Is It](http://www.icebike.org/Articles/howslippery.htm)).
Braking must be done with great care, and principally with the back brake. The front brake of a bicycle supplies way more braking power than the back brake. The more it works, the more weight is transferred to the front wheel, and the more the braking force applied to the contact patch.
The problem in winter is that you will quickly break traction with the front wheel. Once you do, your chances of remaining upright are minimal. Reserve the limited traction of the front wheel solely for steering. Brake with the back wheel. Transfer weight rearward, (stick your butt out behind the seat), to keep as much weight over the braking tire.
As long as you can steer you have a good chance of remaining upright. This is why if you only have one studded tire it belongs on the front. It is also why you want to avoid braking with the front wheel on black ice. Even with a locked up rear brake, and the rear wheel skidding, as long as you stay off the front brake, you can steer all the way down icy hills too slippery to walk.
[/INDENT] **![](http://www.icebike.org/images/TractionInTheSnow.jpg)Ride the Grit or Fresh Snow**
[INDENT] At the side of the road, there is usually an area covered with sand and other debris swept there by car tires. Sometimes there is just fresh untracked snow there.
In Black Ice conditions this grit becomes "glued down" by the same ice that is covering the road. Its like riding on sandpaper. There is far more traction in the girt than on the Black Ice itself.
Similarly, when there is some snow around, the snow will often provide more traction than the ice. Even light snow directly on top of Black Ice may provide better traction than just the Black Ice. This is because snow is angular, and the angular particles catch and bind on on another, your tires, and the ice below.
Once melting starts, snow can add to the slipperiness of the underlying ice, so occasional tests with the rear brake give you a good idea of the traction below.
[/INDENT] **Studs**
[INDENT] Studded tires are great on Black Ice. In fact, this, and hardpack are the best areas for stud use, they are largely wasted in deep snow.
Studs will provide amazing traction in black ice, and the more studs the better. In fact, you can get down right cocky with the amount of traction you get, and that's when you find out that all good things have limitations. You still need to be careful with turns and braking. But you can at least consider using just a little front brake.
[/INDENT] **Techniques**
As mentioned above, look for the traction, stay off the front brake, and wear your studs.
Test Black Ice conditions when going straight, by slowly applying the rear brake till you get a feel for how slippery it is. As soon as the back wheel skids, let up on the brake. Its best to do this early in the ride, so you will have an idea of how long it will take you to stop. Watch hills. Especially watch sharp corners, slow down, drag the foot that is on the inside of the turn. DO NOT BRAKE in the TURN. Your back wheel will spin out if you do.
Finally, watch it when you come to a stop. Bike tires, with or without studs, always seem to have more traction than shoes. Its embarrassing to blithely handle 10 miles of black ice and fall on your butt at the front door.
From http://www.icebike.org/Articles/TechniquesBlackIce.htm: