[motorcyclistonline] - Riding Tips: Traction, Acceleration, Braking – How To Avoid Ex

[Ninjette Newsbot]

Racers spend their careers exploring thresholds. Said Marc Marquez after his crash at Mugello: “I was going over the limit every corner and then in the end I crash.”


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One definition of a threshold is the level of intensity that must be exceeded for a certain reaction, result, or condition to occur—how much throttle it takes to accelerate, for example, or how much brake to slow or stop. A threshold can also be the point of excess—how much is too much gas, too much brake, or too much lean angle. Riding is an act of balancing those thresholds.

Both can be daunting to new riders even just attempting to set a motorcycle in motion. Finding the clutch engagement threshold and balancing it against the throttle threshold to move without lurching forward or stalling requires nimble coordination. Brake application also holds surprises for inexperienced riders. Blowing past the brake-engagement threshold with an unfamiliar hand-controlled lever can cause jerky stops or worse.

"The grip-limit threshold is much higher than most riders imagine it to be. Becoming familiar with this threshold improves a rider’s crash-avoidance ability."

Rolling on the gas to drive off a corner is another threshold event. Acceleration does not commence with the first fractional throttle opening, as riders sometimes fear. At a brisk pace with moderately aggressive lean, threshold acceleration does not begin until somewhere between 10 and 40 percent of throttle opening, depending on the turn’s radius, camber, and elevation characteristics, as cornering forces, tire friction, and gravity itself must be overcome. With the throttle just open a smidge, riders often notice they could have been more aggressive with their roll-on if they’d only crossed the acceleration threshold sooner.

Our most common riding questions revolve around thresholds. When do the tires slide out and cause a crash? How hard can you brake before you lock up the front tire? If you open the throttle too quickly, will you wheelie over backward and end up on your head? The pivotal questions always remain the same: What’s too much and what’s too little?

Riders who avoid quick directional changes for fear of washing out the front tire exemplify this confusion. Being unfamiliar with the tires’ grip limits, they imagine the forces generated by quickly snapping the bike over to full lean might exceed the grip threshold and cause a crash. This is possible, of course, but given acceptable tire, road surface, and temperature conditions, not very likely. The grip-limit threshold is much higher than most riders imagine it to be. Becoming familiar with this threshold improves a rider’s crash-avoidance ability.

Not so long ago, finding peak power/traction thresholds was a precarious proposition. Back in the early ’90s, peaky, two-stroke, 500cc GP bikes required uncanny skill and sensitivity to ride fast. A good rider had to be able to dial in just enough power beyond the absolute traction threshold to produce wheelspin for, among other things, slide-steering and awesome, crossed-up corner exits. Exceed that threshold by too much, of course, and a spectacular high-side crash was the result.

Electronic controls have since radically altered how riders interact with these thresholds, both on the racetrack and on the street. Antilock braking systems, traction control, and even slide control are all readily available and will only improve in the near future. Some bikes already allow you to tailor varying degrees of wheelspin for each individual corner. Predictive slide control is even rumored to be on the digital horizon. Wheelspin is now monitored in milliseconds; human reaction time—roughly 100 times slower to respond—is simply no match for modern electronic rider aids. These have made the various thresholds less scary but no less important.

After training more than 10,000 students at the California Superbike School using BMW S1000RRs equipped with a full battery of electronic rider aids, I’ve discovered that a rider’s understanding of the core technical skills—specifically understanding and navigating these same acceleration, braking, and cornering thresholds—still remains our top training priority. Even with all the electronic safety nets, mastery of these core basics builds confidence and leads riders to a fuller appreciation of how to skillfully incorporate electronic controls into their riding and utilize them to their greatest advantage.

Keith Code, credited as the father of modern track schools, founded his California Superbike School in 1980 and currently operates programs in 11 countries and on six continents. His "A Twist of the Wrist" series of books and DVDs are thought by many to be the bible of cornering.




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