(Charlesbusa @ Aug. 03 2007,22:46) To more easily describe trail braking, you have to first describe what a racer is doing prior to trail braking. The racer is braking at 100% maximum. All or almost all weight is compressing the front suspension and tire. Trail braking can accomplish 2 things. 1)Carry more speed going into a corner. 2)Keep the front suspension and tire compressed to give more traction and not upset the chasis by releasing all the compressed force quickly.
You can carry more speed into the corner because you are using 100% of your tires traction at all times. Example, 100% of tire's grip goes to braking when straight up and down and 0% to cornering. 50% goes to braking and 50% goes to turning when the bike is somewhat leaned over. And finally 100% of the tire's grip goes to cornering at the apex with 0% going to braking. This is a smooth process that must be balanced between braking and cornering depending on lean angle.
Ever see MotoGP riders crash going into a turn with the front wheel turned, yup too much front brake. After maximum braking you don't want the chasis making any big movements going into a corner, such as releasing the front brake all at once. Also by gradually realeasing the brake, you keep the suspension compressed which gives your more traction. The braking force that initially compressed the suspension and tire gradually gets replaced with ?centrifugal? force keeping the suspension and tires compressed when at full lean.
Pro-The fastest way around the track.
Con-Too much brake and you lowside.
One way of using the rear brake on entry is normally called "backing it in". Easier to do on lighter bikes(like dirt bikes
).
Pro-Can be faster or as fast or maybe not quite as fast as trail braking with the front.
Con-Too much slide and you'll either lowside or high-side
Both of these techniques should only be used on the track.
On the street you always need to leave yourself a little extra, just in case. Never go at your limit on the street.