Saturday, December 31, 2011

Cornering Done Right !



                                                                    PROPER CORNERING - A MORE ADVANCED APPROACH

When learning the basics of cornering, most riders begin with a series of action in a particular order; shut throttle, apply brake or brakes,  downshift and steer into the corner. As we progress, these previously separate inputs begin to overlap one another and sometimes occur simultaneously. This smooths the process and gives us better use of the time we have to execute them.

Rather than first shutting the throttle, then reaching for the brake, then downshifting, then steering, we begin by shifting our body position to the inside just prior to applying the front brake lever while smoothly rolling off the throttle. As soon as we've scrubbed off enough speed we begin blipping the throttle to match engine revs on our downshifts as early in the braking zone as possible. We do this so that as the corner approaches, all of our attention can be focused on precisely setting our corner entrance speed and properly choosing our turn-in point.

As we advance our riding technique and smooth our transitions further, we slowly release brake lever pressure as we approach the turn-in point and trail off our braking as we increase our lean angle into the corner. This allows the front suspension to remain compressed which steepens the effective rake of the chassis geometry, in turn allowing it to turn in quicker, with less effort than with the fork extended. Most importantly, it smoothes the weight transfer from front to rear and minimizes the changes in suspension stroke and chassis geometry. In simpler terms, the fork moves from its fully compressed state at or near the bottom of its stroke under maximum braking, to where it will settle under cornering load,somewhere between 70 to 80 percent of its travel.



This is a lengthy lead in but is necessary to understand the next steps in executing proper cornering. Now that we've steered into the corner and set our lean angle, we arrive at the subject of controlling our cornering arc with the throttle.  One of the most important missed steps in advancing rider skill is getting comfortable using the throttle to control cornering arc while leaned over in a turn. As with all advanced skills, absolute smoothness is a must.  Even with today's incredibly advanced traction control electronics which use GPS systems to allow teams to dial in the percentage of tire slippage on a corner-by-corner basis, the best riders in the world (think Valentino Rossi and  others) use the throttle as a rheostat in infinitely small increments when both opening and closing the throttle. The fact remains however, that the fundamentals of smoothness still apply. Electronics are no substitute for experience and ability.

In the real world , for most riders who ride with their wheels always aligned, the smooth use of the throttle while banked into a corner is an indispensible tool to precisely adjust your line through a corner. Your bike's trajectory  through a corner is primarily determined by two factors: your speed and your lean angle. Increasing your lean angle obviously tightens your cornering line.  Increasing your speed has the opposite effect.To put it another way, once you've set your lean angle you can tighten your line by simply reducing your speed or widen your cornering arc by increasing speed, without having to change your lean angle. Keeping your engine rpm between 60 and 80 percent of redline also enhances its throttle response. Higher rpm's however require more smoothness on the throttle.



As cornering confidence builds even further, riders  focus most of their attention on lean angle, and achieving ever increasing levels of it. This is where things can go very wrong.  When constantly pushing  cornering limits, riders often find themselves in the position of needing to alter their line mid corner, and panic ensues. When we, as riders panic, we tend to do a predictable number of things; we tense up, we target fixate, we slam the throttle shut and we grab the brakes.  All of these actions seriously affect our ability to control the motorcycle and put us in a precarious state. It's better to practice controlling our speed as well as our lean angle going into the corner before panic sets in midstream.

When a rider is comfortable leaning their motorcycles into the corner it becomes important to learn how to vary the throttle position as well.

After steering into the corner and setting your corner speed by trailing off the brakes, there is a point where you need to slightly open the throttle to neutral throttle.  This is the point at which you maintain the desired speed by neither accelerating nor decelerating. If you don't  open the throttle, the bike will continue to slow, and corner in an ever-decreasing arc. , It is this situation--the feeling that the bike is falling into the corner--that triggers the panic reaction that many riders find the most difficult to overcome. The solution is to open the throttle to the point where it both stops the lean angle and increases the speed to widen the cornering arc. Although this sounds simple, our instinctual panic responses are programmed to do the exact opposite, as was mentioned above. By either avoiding panic mode while at the same time increasing our speed and lean angle in small increments, we can keep ourselves out of trouble and in control.  I know it is easier said than done, but in time it does become a much more natural response.

The opposite situation is when you need to tighten your cornering line while you're already at the maximum lean angle limit that your confidence allows. Here is where the need for sublime smoothness on the controls is most needed. The degree of input while rolling off the throttle to tighten your line is merely a few percentage points of the quarter-turn available. Imagine that neutral throttle is 17 percent of the total throttle opening. If you're nearing the physical limitations of the bike chassis, simply shutting the throttle completely could overwhelm the available traction by transferring more load to the  contact patch of the front tire. The tire may not be able to handle these additional forces. In this rare but critical instance you need to have the "feel" to relax the twist grip perhaps as little as two or three (or at most five to seven) percentage points of available throttle angle to tighten your cornering line. This slight reduction of throttle will transfer the bike's weight distribution forward, gently compressing the fork and increasing the front tire's contact patch, both of which will enhance the bike's ability to steer into the corner. These factors, as well as a slight reduction in corner speed all combine to tighten your cornering line. Too much reduction in throttle, however,could cause the fork to compress to the point of compromising cornering clearance or overwhelming the available traction of the front tire.
In a case such as this, delicate application of either the front or rear brake can be used, but that's a different subject to save for another editorial.



The bottom line is that cornering is a delicate balance best executed with a calm, practiced touch. It is learned  in gradual increments along with equal awareness of how lean angle and throttle position affect our ability to adjust cornering lines in those perilous mid-corner moments that life can throw at us.

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Ride on!

Josh