Ienatsch Tuesday

Motorcyclist’s Effect On Radius And Risk

Fear and Lean Angle, Part 4.

Updated: April 14, 2020

Welcome to Part 4 of our Fear and Lean Angle study. This week: The on-board engineer’s role in lean-angle-reduction.At the Apex Photos

In Part 1 of this series, we discussed my habit of holding the brake lever longer than Chris Peris or Kyle Wyman when we’re lapping together. That extra trail-braking reduces my midcorner speed to match my lean-angle risk level tolerance. My tolerance levels are lower than theirs so I go slower to run the exact same lines. I’m more scared than they are.

We equated lean angle with risk because a tire’s traction is divided between lean angle and/or brakes and throttle. I’ve admitted that while I might have the skill to run the lean angle of Chris and Kyle, I did not have the motivation to risk the possible consequences.

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What’s the reward? That is the key question we ask ourselves to help street riders, trackday participants, and non-professional (no money) roadracers find sensible answers.

In Part 2, Freddie Spencer’s thought of We want to run maximum lean angle for the shortest time possible ruled the article. Read that carefully: The world champ wasn’t saying don’t lean over to maximum, he was exhorting us to spend as little time at max lean angle as possible. This is because riders who enter corners at madcap speeds (no trail-braking) spend all day to get direction—meaning their exits suffer. And this sport is all about exits. Street riders who run into corners sans control (brakes) and rely on deep lean angles will eventually be hurt by their ever-changing surroundings and unforgiving road verges.

In Part 3, we ran through logical, linear ways we can improve our lean-angle confidence, and confidence comes from healthy progression: As in, staying healthy so you can progress! I admitted to raising my lean-angle tolerance throughout an AHRMA racing weekend as successful lapping increased my confidence in tire performance. I got braver in little, successful steps.

Part 4: The Onboard-Engineer’s Movable Mass

At ChampSchool we put it quite simply: The primary reason to hang off to the inside of the bike is to run less lean angle at the same cornering radius. My smart engineer friend goes a few steps further, telling us it’s the combined bike and rider center of mass that affects lean angle, so if we can move that combined mass inside of the bike’s centerline, we run the same radius on a meatier part of the tire. The contact patch only recognizes one mass—the combined mass of bike and rider—so riders who move their center of mass (chest) to the inside can be safer. This engineer friend is a ChampSchool grad, so safer means less risk because lean angle is equated to that risk.

So riders, we gotta move to the inside of the bike. Draw a line straight up from the center of your fuel tank and get your head and chest to the inside of that line—to the right side for right-hand corners, the left side for left-hand corners. Or take more risk.

You Mean, Hang Off Like Márquez?

Yes, on the track. But if you or your friends are hanging off far enough to drag a knee on public highways, you will run out of time to react because your cornering speeds will be so high. Go to the track! Part of the reserve we should ride with on the street is a reserve in body position.

ChampSchool’s David Bober demonstrates ideal street body position: Knee out slightly to support his upper body that has moved to the inside of the bike’s centerline. He is poised to move more if necessary.Highway Jon Photo

ChampSchool’s Ryan Burke demonstrates how much riders can do with their upper body. Note that his knee is out slightly to help support his weight on the right footpeg. If you practice this all-in upper-body move, you will be ready when gravel appears across the lane in a blind right-hand corner. Same radius, less lean angle: Game changer.Burke Collection

Same rider, same corner direction, different bike—what’s changed? Ryan has moved his butt off the inside of the seat and flexed his right knee out toward the ground, fully committing to the advantages of body position. This is the least amount of lean angle that Ryan can run on this bike at this pace in this corner. For the street, not moving our butts, or moving them only an inch or two, helps remind us that we must ride with a reserve for the unexpected. Personally, I find that limiting my body movement limits my street speeds.Luke Hummel

My friends Glenn and Catherine Dickerson are excellent examples of riders who use a lot of body position on the street but combine it with the discipline to limit their cornering speeds. Their body position allows them to reduce lean angle, and their discipline reminds them that the street is not a racetrack. Of course, they’re lucky because they live at a racetrack!Dickerdog Collection

I love my AHRMA brothers and sisters deeply, and I want to speak to them in this article: The more you can imitate the body positions of GP/SBK/MotoAmerica champions, the safer you will be. Faster too, but more importantly, safer. Here, Andrew Cowell leads a student in the AHRMA school (graduate from school on Friday, race the weekend!), illustrating the student’s next steps in his progression: body position. See how the student’s head is on the high side of the bike, making his ride riskier…and slower.AHRMA

Timing Too

What is not discussed enough is the timing of our body in its movements. Everyone talks about position, but how and when we get in position will close this article and this series.

Think of your footpegs as axes (plural of axis, really!) of the gyroscope that is your motorcycle. At the point you want your bike to begin turning, move your head in that direction. If you’re in combination corners, move your head from side to side to match the time you’d like to load that inside axis.

Most of us move too fast, too soon. We lurch to the side and then have to pull the bike down on top of us. Slow those movements, time them with your desire to divert your bike’s path from upright to turning. We’ll close with my friend Shane Turpin’s memorable advice:

Shane Turpin has been consistently quick for decades on a wide variety of bikes. This champion’s advice on riding, especially body-position movements: “This is a symphony, not a rock concert.” Smooth out those body movements, time them with your bike’s direction changes. Jumping or lurching around on the bike can be just as bad as grabbing and stabbing at the controls.Turpin Collection

More next Tuesday!