Safety of Wheelie
Leaning back too far (i.e. as a result of pedalling too hard) will cause the bike to fly out from under the rider. Although most riders will instinctively hit the ground running, practice recovering from this event before attempting an actual wheelie. Balancing left to right can easily be controlled in the air by moving the knees and handlebars back and forth.
Injury can be avoided by keeping speeds down and/or learning to use the rear brake. However, higher speeds, counterintuitively, are often necessary to master the wheelie as more balancing skills are necessary with decreasing speed, which are usually not present without sufficient practice. For this reason, beginners attempting wheelies on bicycles should tune up their rear brakes and aim for an 12-18 km/h (8-12 mph) wheelie for maximum safety. Although a wheelie or manual can be easily achieved without the use of the back brake it is always recommended that the lever is covered. Never have the entire fist closed around the bars because if the balance point starts to become to far back there will not be enough time to grab the brake and at that point the rider may fall off backwards. A grip is needed on the bars so only one or at the most two fingers are required to use the back brake lever. The seat height will determine the outcome of going over the back, the higher the seat the harder it is to land on the feet.
Beginners should use a low seat height until comfortable with the balance point and back brake. It is harder to maintain speed with a low seat height so wheelies may be short but once comfortable raising the seat height will make the front wheel more eager to come up and make maintaining speed a lot easier. It will also make the balance point easier to fine tune as there is more weight above the back wheel to move back and forth.