When exactly you will wash out on a turn is determined by the traction between your tires and the terrain surface being less than the pull of centrifugal force, itself a function of your turn radius and the square of your speed.

Leaning

All of this assumes, of course, that the rider leans the right amount into the curve. The biggest mistake novices make is to be timid about leaning, and this slows them down as much as improper cadence. You can lean in as much as 45 degrees perfectly safely if your speed merits it on a bike, and motorcycles end up nearly flat when cornering at still higher speeds. Racers find that in the heat of competition they lean much more than they'd ever dare in everyday training, and they certainly live to tell the tale. Provided you have the traction and speed, there's no limit other than the psychological to leaning in.

There are two main ways to lean into a turn. The first, and more suited to trails, is to keep your body relatively upright while you press the bike down, sometimes nearly horizontally, keeping your weight on the outside pedal and the inside handlebar. This is acceptable for turns where performance is not critical, and traction is uncertain, as it is really easy to recover if the dirt gives way, and you keep the bike between the ground and your flesh.

The better way to turn is to stay in your aerodynamic tuck and simply lean over. This is the best idea for hard-packed trails with no surprises, or pavement. It is the style to choose if you need every bit of turning ability you can scrape up, because you entered the turn going much too quickly and don't want to have to be scraped off a telephone pole. You can lean right down to 45 degrees at high speeds, and if you're on blacktop it's pretty hard to screw it up.

If you choose to lean, instead of pushing your bike down while you perch above it, you can still pedal. Up to surprising angles, too -- at 28 degrees with toeclip pedals, and with the better clipless models, down to 36 degrees. If you've ever leaned at 28 degrees, that's steep. You want to pedal at all times, unless you're turning so quickly that the lean angles cause the inside pedal to hit the ground. If you can still pedal, then you're not going fast enough, but beware of pedalling when your clearance runs out -- you can lift the entire rear wheel off the ground and skip as much as a metre to the side. Not only does it scare the hell out of you, but it's definately a bad plan during a screaming descent.

Tire Pressure

Reducing tire pressure will both improve traction (to a point!) and reduce your speed, making cornering easier. Motorcycles, for example, operate with very low tire pressures because the motor can soak up the inefficiency much more readily than a rider can. Road riders generally want to inflate their tires to near the labeled maximum, usually 120 to 170 PSI, and will not want to throw away the speed that provides that except for unusual situations.

When traction is paramount, using about half that pressure -- so there is a noticeable bulge when riding -- will help at the expense of significantly higher rolling resistance. With less pressure, the patch where the tires meet the road surface will be significantly larger. However, the wasted energy of rolling resistance will get soaked right into the tires, increasing tire pressure, and temperature, which can be critical enough after half an hour of steady braking on a mountain downhill for the glue holding sew-up tires to your rims.

Speed

Dump your speed before the turn, not in it. Turning while you've got all of you front wheel's traction earmarked for braking is a recipe for disaster. To lose speed as quickly as possible before an unexpectedly severe turn, squeeze your rear brake moderately, and you front with full force. When you feel the rear wheel begin to skid, you know that almost all weight has left the back, so ease off on the front brake. To put off the point where your rear wheel loses weight as much as possible, slide back as far as you can while still being able to pull the brake levers, right off the seat. Keep this up until either you're happy with your speed, or the turn begins.

If the corner turns out to be sharper or the traction poorer than the rider had anticipated, of course, the rule of slowing before the turn becomes hard to follow. Or perhaps the grade through the turn is so steep that you accelerate more than the turn can handle. The best bet is to leave enough margin in you speed to stick to your line without things getting too dicey if you discover some sand. Cutting things too fine and falling will end your race as quickly as the beginner's habit of slowing down too much.

If you must brake during a turn, keep in mind that you traction, on your front wheel especially, is all used up. If you are in danger of sliding out, straighten your turn out slightly as you apply you rear brake. Although it lacks the stopping power of the front, your rear brake contributes far less to a skid when turning.

If the Situation is Serious...

Well, you do have a bit of a problem here. Your best bet is to keep doing emergency braking deep into the bend, turning slightly, until you start to run out of blacktop. Ease off the brakes as you slam into the turn, and if the turn is really fast no amount of braking is possible.

You'd be amazed at how fast you can take a turn if you lean in enough, so just steer around the turn and you'll lean right over. Stay in your riding position and lean with the bike to about 45 degrees, rather than just pushing your bike flat beneath you. Yes, that's a lot, and it feels suicidal, but it's perfectly safe on blacktop, and it's your only hope.

Anticipate

You may be thinking, after seeing this headline under so many topics, that it's the key to cycling. It's not. It's the key to nearly everything in human existence. Think ahead.

Anticipate your route. At the apex of the turn, come as close to the inside shoulder as you can, entering and exiting the turn at the outside shoulder. Look well ahead, especially when going quickly. In the turn, look for sketchy spots and flatten out your turn over them. A little bit of slowing gives you a lot more tire grip.

You're best off anticipating the turn and braking too much, too soon, than to be a negligent knuckle-dragger and do too little, too late. It's much easier to pick up the speed again after the turn with a few strong strokes rather than picking up pieces outside the turn with a spatula.

Anticipate your gearing. Shift gears before you enter the turn, so that when you come out of it you'll be able to get back to speed as quickly as possible.

Remember that on a high speed descent, the important thing is safety, not having fun or going fast. It is easy to let your attention lapse and ride over a patch of gravel, or enter a turn too quickly. Be alert and attentive mhen travelling at high speeds, or your brain bucket might not be enough.