Cornering Analysis

The 4th stage of the ’09 Tour de France highlighted the Team Time Trial (TTT). The TTT requires many skills from all 9 riders in the team “train.”

Among them are obviously speed, power, and endurance- which are needed to keep such a high rate of tempo for the entire TT distance.

But one of the most overlooked skill in any type of bicycle riding is; bike handling skills. In fact of all the acquired skills of riding, handling skills are by far the most important.

During today’s stage, team Bbox showed the importance of understanding, focusing and implementing the mechanics of cornering, or lack thereof in their instance.

Four of their nine riders rode right off the road in a sweeping right hander. The turn wasn’t that tight, nor was it a decreasing radius corner. It was basically a constant radius, flat basic turn.

Once the first rider of Bbox drifted wide, missed the apex and began to go off the road, three others follwed him! Why? Simple. Target Fixation. Besides knowing how to corner properly a rider needs to know how to avoid following a wreck or the same path of carnage.

This is where quick and firm Countersteering comes into play.
More about countersteering later.

A corner is made of three basic elements. The entry, (turn in point – “tip”) the apex, (the middle or center) and the exit (the end of the corner).

There is a proper way and an improper way to corner efficiently, safely and quickly. Bbox showed the world how NOT to corner, while team Saxo Bank and team Astana among others, showed how to perfect a corner.

To be somewhat fair, in a TTT, riders are riding time trial bikes- which are usually more rigid, have more rake in the front end to be aerodynamic and subsequently, are more unstable in corners.

But that’s not to say these riders get a pass on their lack of good handling skills. These guys are in the pro Peloton. They are supposed to the best of the best- but that’s not always the case.

While some of these riders are amazing climbers, sprinters and all around good endurance and power athletes- they are not necessarily all-around good bike riders. What makes a complete rider, is all the aforementioned, plus knowing and understanding how to Steer, Turn and Brake properly.

Steering, Turning and Braking– are the core skills of bike handling.

The entry is where turning/steering starts and the rider begins to lean into the turn. The apex is the point where the rider reaches the furthest point on the inside of the turn and the exit is where the rider can start going upright so as to pedal and power up again.

There are 4 basic laws of physics- gravity, inertia, traction, and balance as they apply to cornering. The laws of physics dictate that when a bicycle is leaned over, the position of its center of gravity will  influence the lean angle of the bike.

In addition to kinetic energy, a rider has two other forces working on the body and the bike- Gravity pulling you down, and Centripetal Force pulling you either left or right- depending on which way the rider is turning.

The lines in the above picture display the forces during cornering. The illistration is designed to better understand these basic forces involved when cornering.

The bottom line on the graph represents the road which induces frictional forces. The horizontal line is the centripetal force and the vertical line, represents the force of gravity.

Countersteering

In short, counter steering moves the wheels out from under the center of mass. It involves turning the front wheel in the opposite direction you want to turn the bike, be it a motorcycle or a bicycle. Counter-steering is achieved by pushing on the inside of the handle bar in the opposite direction you actually want to go.

Select your turn in point as you approach a turn. But before reaching your “tip” look through the turn and select a reference point (RP). When you reach the “tip”, begin to steer (countersteer).

It is important to intiate firm countersteering- to keep the right trajectory and proper line.  As the rider nears the apex (a single apex corner) and has the need to turn more sharply to keep from running wide or off in the turn, the rider turned in too early.

A gradually, early turn in has the rider following a parabolic path, a wide arc at first that tightens until maximum lean or turning is reached near the apex. This is an example of “lazy” steering. This often results in a rider(s) missing the apex which causes a dramatic slow down and/or riding off the road.

Turn in slightly later but quicker and the rider follows a more circular path that requires less lean angle but reaches the apex sooner and is able to hold the arc longer. This technique is known as “squaring off” a corner, which usually enables a rider to carry more speed/momentum through the corner.

Many riders don’t bother to work on their cornering technique and when it’s crunch time- find themselves in a time losing situation. Today, those 4 Bbox rides cost their team precious time– in a race against the clock, seconds and as it turned out, hundredths of a second enormously count.

Some quick tips:

• Use counter steering (pushing on the bars) more so than leaning your body
• Look through the turn (keep your eyes up and looking down the road)
• Keep light to moderate pressure on the bars
• Pivot your hips to assist counter steering

(no death grip- this allows the bike to follow its  ‘natual’ centrifugal path – by holding too tight you  prevent the front end from following its inherent course- this causes the already rigid front end to become even more unstable)

• Use the brakes sparingly and try not to brake much when the bike is mid corner or when you are leaned over

Remember, a bit slower in…but almost always faster out.

 

Four wheels move the body. Two wheels move the soul

 

Author is a former WERA and CCS sportbike and grand prix roadracer