Lean angle, By Nick Ienatsch

lean angle

Working on increasing lean angle needs to be done in a controlled and safe manner.KTM

When a new rider tells the YCRS instructor crew, “I want to carry more lean angle but I’m scared.” We answer, “Us too!”

 

At YCRS we equate lean angle with risk and use the two words interchangeably. A core school value centers around what makes up front- and rear-tire grip, and you can see it in our video, 100 Points of Grip. We are constantly balancing braking and throttle “points” against lean-angle points. The more risk (lean-angle points) we carry, the fewer brake and throttle points are available. We are closer to the edge of grip with more lean angle, and that should always spark our self-preservation instincts.

 

A few columns ago I described the “old man’s disease” I suffer from when compared with my fastest instructors who lean over farther than I dare. Leaning a motorcycle over is perhaps the single-most enjoyable part of riding, but lean angle is not just enjoyable, it’s central to steering a motorcycle through a corner. I push myself to run more lean angle on the racetrack to improve my lap time; new riders must become comfortable with lean angle to ride a motorcycle safely.

 

All things being equal, the more lean angle a rider carries through a corner, the faster we can go at the same radius. Newer riders become frustrated with their slow corner-entry speed because they are not comfortable with adding more lean angle. Veteran riders who are lean-angle nervous begin to lose the joy of riding.

 

This BTC article hopes to give you a plan and method to safely increase your lean-angle comfort. And remember this, new riders: We’re all in this together!

Incremental Increases

 

In a nutshell: To carry more lean angle a rider must enter the corner faster if all other things are equal. You know that, I know that—but can we convince our brains that the tires will stick? Will they stick? “Nick, can you guarantee that my tires will stick if I enter the corner faster?”

 

No, I can’t. But I can guarantee that our tires will gently and smoothly slide slightly if we gently and smoothly increase our entry speed. We might think, “I can get into this corner 20 mph faster.” But if we adopt an “incremental increase” approach, we can enter the corner 1 mph faster 20 times in a row and then discover that at 17 more mph the tires are at the limit. They will gently slide and whisper, “That’s all I’ve got.” If we had tried for a 20 mph increase in one pass, we would have crashed immediately because the tires went quickly beyond their grip limits.

 

Train Our Brain

 

Increasing entry speed in a linear fashion makes sense when we realize what the challenge is: Training our minds to realize the higher entry speed won’t hurt us! In my world, most of my laps are on school bikes on Dunlop’s excellent Q3+ with nothing on the line, no reason to push. Then I arrive at a track to race Rusty Bigley’s TZ750Chris Carr’s GPz550, and especially the Speedwerks’ NSR250 increasing entry speed for added lean angle is all I work on! My brain is grooved for streetbikes on street tires but must grow to the pace of racebikes on race tires if I want to do well. So, new riders, take heart: We are all working on increasing lean angle while retaining safety—emphasis on while retaining safety.

 

Necessities for Improving

 

If you study the 100 Points of Grip video, you will see that traction is on a sliding scale depending upon pavement temperature, moisture, tire temperature, and tire compound. In other words, we can’t expect a cold tire to run the lean angle of a hot tire. “Yeah, I know that,” you think, yet almost every YCRS instructor has crashed on a cold tire, asking too much of it. So use our mistakes as a reminder that tires must be warm before asking for too much performance. Until they are warm, we must run less lean angle, less brake pressure, and less throttle pressure. Sometimes in the rain that means we hardly lean over all day, and our lean angle additions (and brake and throttle) are extra smooth.

 

To experiment with lean angle, we need:

  1. A linear, gradual, and smooth approach to adding speed.
  2. Hot tires that are not worn out.
  3. A nice day.
  4. Clean pavement.
  5. A repeatable corner, such as lapping at a trackday or a clean and safe parking lot.
  6. A scrubbing line on the rear tire.

Scrubbing Line

 

How do we know if we are running more lean angle? Feeling? Yes, but how about this: Draw a line on your rear tire from the edge to the center with a sharpie or paint pen. Draw it at the valve stem so you can find it easily. Now incrementally increase your corner entry speed and begin to scrub that line off.

 

Note that it is the rear tire we are examining because many bikes will not use all of the front-tire contact patch.
FJR1300 rear tire

The scrubbing line on my FJR1300′s rear tire tells me I had additional lean angle available during my last ride. This gives me confidence to add lean angle on my new-to-me sport-touring bike if the pavement is suitable, the tire is warm, and I stay linear. – Nick Ienatsch

 

Note that some bikes will drag footpegs and hard parts before they will use all of the rear tire; if you have a bike like this, then the gradual, linear increase of lean angle makes sense because riders who “flick” the bike into the corner can lever the tires off the ground and crash. Linear steering helps with tire traction and gently touching hard parts to the pavement.

 

FZ1 rear tire

This is my FZ1 rear tire after a day at Colorado’s High Plains Raceway, a tremendously safe place to scrub the scrubbing line right off. – Nick Ienatsch

front tire

This is my FZ1′s front tire from the same High Plains Raceway school and note that all the tread is not used. I see this on most if not all the Yamahas we use at Champ School: in other words, add a scrubbing line to your rear tire and let that be your guide. – Nick Ienatsch

 

When Should Maximum Lean Angle Happen?

 

As we experiment with lean angle, we can’t forget tire loading! Maximum lean angle in the majority of corners happens as the bike finally slows to match the radius, at the end of the trail-braking zone or deceleration zone if it’s a corner we don’t brake for. Maximum lean angle should happen with a closed throttle and might last for some distance with a neutral or maintenance throttle (just enough throttle to keep the bike on line) until the corner opens and we can take away lean angle.

 

Be cautious of getting so enthralled with lean angle practice that you begin to add lean angle with the throttle open. That means weight is off the front tire, yet adding lean angle is asking that front tire to work. Get back to the 100 Points of Grip video and other articles on Ienatsch Tuesday to realize that a tire must be loaded if we want it to seriously grip.

“Seriously grip” means significant lean angle, brake pressure, or throttle pressure and gets us back to the reminder that almost any technique works at slow speeds and low tire loads. If we want tires to grip with significant pressures, they must be loaded—and in this discussion, it means maximum lean angle with the throttle shut or very slightly opened—not yet accelerating.

 

To be specifically clear: If we are adding lean angle and throttle, we will either lose front grip (unloaded front tire) and crash, or lose rear grip (overloaded rear tire) and crash. So in this lean-angle practice and for the rest of our riding careers, we must let the bike turn down to whatever maximum lean angle we need for the corner off throttle, and only begin serious acceleration when we can stand the bike up as the corner opens.

 

maximum lean angle

Your maximum lean angle on the street must include the ability to add more if needed in an emergency. – Jeff Allen

 

Street Riding and Safety Margins

 

Experienced veteran riders have a safety margin in hand while street riding to deal with the unexpected, and one of the most vital safety margins is lean angle. If we use maximum lean angle consistently on the street, we will be caught out by unexpected traction and radius changes. That said, we must experiment with approaching our bikes’ maximum lean angles in a controlled environment so we can ride confidently in corners. Having a margin we are familiar with is vital. “I can lean over farther if necessary” comes from consistent and linear practice and soon replaces, “I hope I can lean over farther.” This is why an occasional trackday is so helpful: safe lean-angle practice in a controlled environment, using the scrubbing line to incrementally increase comfort at additional lean angle.

 

More next Tuesday!