How to Handle Downhills
For downhilling you have to keep your centre of gravity low and to the rear of the bike.
To do this you have to get your rearend as far back on the bike as possible – even to the point of where the seat is in front of your stomach). This is why it’s a good idea to lower your seat in advance to make it easier to slide back over the seat when redistributing your weight.
When downhill braking you have to avoid locking up the rear wheel (and gouging the trail) and losing it’s effectiveness by sliding down the hill. You also want to avoid going over the handlebars by locking up the front brakes. While maintaining rear brake pressure, balance the amount of braking pressure applied to the front wheel by varying (often referred to as “modulating”) the pressure of the front brakes enough to avoid skidding the back tire – but not too much that the rear wheel lifts off and you go over the bars.
Now your ready to start practicing. Choose a hill with an even, gradual grade which is reasonably hard packed, keep your body relaxed so you are able to react to changes in the terrain. As you go down the hill, practice sliding your rearend over the seat and coasting down the hill, applying your front and rear brakes as explained above. After you feel comfortable with this you can progress to steeper hills. Good luck and happy cycling!