Controlling Your Cornering Arc with the Throttle

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CrashDummy
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Controlling Your Cornering Arc with the Throttle

#1 Post by CrashDummy » Mon Mar 23, 2009 10:46 am

In the real world for riders who ride with their wheels always aligned, the smooth use of the throttle while banked into a corner is an indispensable tool in precisely adjusting your line through a corner. Your bike’s trajectory or curved path through a corner is primarily determined by two factors: your speed and your lean angle. Increasing lean angle quite obviously tightens your cornering line while increasing your speed has the opposite effect. In other words, once you’ve set your lean you can tighten your line by simply reducing your speed or widen your cornering arc by increasing it; without ever changing your lean angle. Keeping your engine rpm between 60 and 80 percent of redline also enhances its throttle response, though the higher rpm also demands greater smoothness.

As riders build their cornering confidence they focus most of their attention on lean angle; specifically, achieving ever increasing levels of it. In their quest for pushing the limits of lean, however, riders often find themselves needing to alter their line mid corner and panic often ensues. We tend to do a predictable number of things when we panic (we tense up, target fixate, slam the throttle shut and grab the brakes) all of them hinder our ability to control a motorcycle. It’s better to practice controlling our speed as well as our lean angle before panic sets in. As riders build their confidence in leaning their motorcycles it’s important to gain experience in varying the throttle position as well.

After steering into the corner while setting your corner speed by trailing off the brakes, there comes a point where you need to slightly open the throttle to neutral throttle, the point at which you maintain your desired speed, neither accelerating nor decelerating. If you don’t crack open the throttle, the bike will continue to slow and corner at an ever-decreasing arc. This is caused by two factors: the first is that, lacking the centrifugal force of hard cornering, most bikes continue to lean into the corner if the throttle isn’t cracked open to arrest the lean; the second is that all other things being equal, simply slowing your speed tightens the cornering arc as well. Ironically, it’s this situation – the feeling that the bike is falling into the corner – that triggers the panic reactions that many riders find the most difficult to overcome. The simple solution is to open the throttle to the point where it both arrests the lean angle and it increases the speed to the point of widening the cornering arc. As simple as this sounds, our instinctual panic responses are programmed to do the opposite: tense up, target fixate, close the throttle and grab the brakes. By either avoiding panic by increasing our speed and lean angle in small increments or reprogramming our ability to overcome panic when we feel it begin to take hold, we can keep ourselves out of trouble and in control.

The opposite situation is needing to tighten your cornering line while you’re already at the lean angle limit that your confidence allows (note that for most but not all riders, this limit is below that of the maximum lean angle that either the cornering clearance of the chassis or the traction of the tires allow). Here is where the need for sublime smoothness on the controls is most needed. The degree of input while rolling out of the throttle to tighten your line is only a few percentage points of the quarter-turn available. Let’s say, for the sake of argument, that neutral throttle is 17 percent of the total throttle opening. If you’re nearing the physical limitations of the chassis, simply shutting the throttle alone could overwhelm the available traction by transferring more load to the front contact patch than the tire can handle. In this admittedly 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. That slight reduction of throttle will transfer the bike’s weight distribution forward, subtly compressing the fork and increasing the front tire’s contact patch, both of which enhance the bike’s ability to steer into the corner. These factors, in addition to the slight reduction in corner speed all combine to tighten your cornering line. Too much reduction in throttle, however, and the fork could compress to the point of compromising cornering clearance or overwhelming the available traction of the front tire.

Delicate applications of either the front or rear brake can also be used but that’s a subject for another column.

However it’s done, it’s a delicate balance best executed with a calm, practiced touch which brings us back to advancing in gradual increments with equal awareness in how lean angle as well as throttle position effect our ability to adjust cornering lines in those perilous mid-corner moments that life can throw at us.


The preceding was the last half of an article by Lance Holst in the April issue of Sport Rider magazine. If you go to Sportrider.com you can read the whole article along with others in their Riding Skills series. And it's free.
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Go into a corner with a little less speed and come out faster

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Re: Controlling Your Cornering Arc with the Throttle

#2 Post by sadmac » Mon Mar 23, 2009 8:44 pm

+1

Or you can just align yourself with the right or left side of fast track lane and do about 80...
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Re: Controlling Your Cornering Arc with the Throttle

#3 Post by CrashDummy » Mon Mar 23, 2009 10:09 pm

The bridge crossing that day didn't show up on my Fastrak statement. :D
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Re: Controlling Your Cornering Arc with the Throttle

#4 Post by Jessika » Tue Mar 24, 2009 8:07 am

Cool article...going to have to see what else I can find poking around in the magazine.
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Re: Controlling Your Cornering Arc with the Throttle

#5 Post by SabreSarah » Sun Mar 29, 2009 10:49 pm

Anyone have the cliffnotes for that post?
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Re: Controlling Your Cornering Arc with the Throttle

#6 Post by sadmac » Sun Mar 29, 2009 11:44 pm

SabreSarah wrote:Anyone have the cliffnotes for that post?
Long story short, the more your on the gas, the wider your line is. So if you need to adjust your line a small amount you can roll on/off the gas to go outward or inward.
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Re: Controlling Your Cornering Arc with the Throttle

#7 Post by SabreSarah » Mon Mar 30, 2009 12:16 pm

makes sense. :-)
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