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Strategies in track riding/road racing: Finding the limits of traction...safely

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#1 · (Edited)
Strategies in track riding/road racing: Finding the limit…safely.

**DISCLAIMER** This is an advanced technique and intended for experienced track riders and/or racers. Use at your own risk. It is also assumed that the rider has proper body position for this exercise. A rider MUST NOT be supporting their weight with the hands during this process as it diminishes front end feel.

I am not a crasher. You know the type; more balls than brains, more money than talent, etc. They possess the remarkable ability to throw a bike into a corner and hope that they go through ok with very little thought or regard for the outcome. As they say, ignorance is bliss and it works for some people. These types of riders can be incredibly fast, and is frustrating to the rest of us because they seem to progress at a pace that is significantly faster than our own.

The downside to this style of learning is that they tend to go over the limit about as often as they reach it, and crashes happen. Because they are not developing a conscious thought process for learning they are simply doomed to repeat these same mistakes until they establish some sort of equilibrium. Some riders get through this stage and move on to become truly impressive riders but the vast majority do not and simply give up either through injury, funding (it is expensive to keep repairing a motorcycle), or through frustration that they can no longer rely on pure bravado to get them around a track.

I have several other writing projects coming and it occurred to me as I planned out what to write that I kept having to move backwards in the process until I arrived here. So, without further ado, here is how I go about learning to reach the limit of traction…safely.

To begin, I need to clarify that I am writing about finding the limit at a corner apex; hitting the maximum corner speed possible to maximize your lap time potential. Finding the limit going in a straight line is a function of machinery. Finding it at the apex is a function of rider skill.

The riders apex is the slowest part of the turn (the apex of the riders line where he/she is leaned over the most. This is not the same as the apex of the physical turn). That should be evident but it bears mentioning anyway. The goal is to hit the apex at exactly the right speed so that you maintain traction, continue your turn in a predictable manner, and exit the corner in the fastest way possible. The process that I use to find this magical speed is as follows:

1) Start slowly. Go through the turn at a speed that you are 100% confident that you can make the turn with absolutely no drama. Do this a few times and commit to memory what your pace feels like. What gear are you in? What RPMs are you at? (If you look at your tach I will donkey punch you. You should know by the sound of the engine/feel of the bike). Are you in the right gear for the turn? If yes, continue, if not, shift and repeat until you are comfortable enough to continue.

What is your trajectory? Where are you tipping in? All of these things must be noted.

2) Once we have established a ‘safe’ baseline it is time to start pushing a bit. DO NOT push your brake marker back. Nothing causes a panic response/survival response like pushing your marker back…that comes later. Instead, brake at the same spot you currently do but either use a little less force on the lever or let off a little bit sooner. Make sure that your tip-in is at the same place as step 1. Our natural tendency is to tip in earlier to account for the additional speed. You need to fight that urge for now. The goal is to go through the turn only 1-2 mph faster than your last attempt. Small bites, young grasshopper.

Because you are going through the turn slightly faster, you will need to increase your lean angle just a bit to successfully navigate the turn. How does the bike feel? This is where your proper body position comes into play. You are light on the bars and can feel the feedback coming from the front tire. Are you able to move the bars?

WAIT!!??!? Move the bars? But you said that mid-corner bar input is bad! Yep, I sure did and normally, it is bad. Adding bar input on top of the cornering forces places a tremendous load on your front tire and is the #1 reason for mid-corner crashes so we must use caution while we proceed. I am talking about adding the slightest amount of bar pressure, the kind of pressure you use when typing on a keyboard or on your phone. One or two pounds of pressure, nothing more.

If you are not yet at the limit, the bike will tip in a little bit further. Make a note of this for your next lap and try to get to this new lean angle as you go through. Repeat steps 1-2 until…

3) Eventually, you will put that slight pressure on the bars and they will ‘push back’. There will be resistance rather than the bike wanting to tip in further. This is often referred to as ‘feeling heavy’ as the bike really doesn’t want to do anything. As soon as you feel that resistance you must immediately release all bar pressure. You are now at the limit of front end traction. Congratulations!

4) Most likely, in the process of finding that traction limit you have now begun to miss the apex of the turn and are now a few feet off of it. Now is the time to adjust your tip in point and brake markers so that you reach the maximum lean angle just at the apex and are able to exit the turn on the proper trajectory. This part is well out of the scope of this document and will be covered at a later date.

Congratulations! You now have the skills needed to learn to find the limit of front end traction.


Riding over the limit

Riding over the limit of traction does not immediately mean that you are going to crash. In fact, pro racers look to ride just over the limit all the time. It is hell on your tires and requires VERY fine control of the bike to do this successfully. There is a ‘grey area’ between 100% traction and crashing which I like to call my ‘slush fund of traction’.

The reason that I mention this here is that during the learning process, if you are applying the above techniques properly you may inadvertently ride over the limit very slightly. This is why we only increase our speed and lean angles in very small increments, so that if we overshoot we end up in this ‘slush fund’ rather than ending up on the ground.

If you happen to go past the limit, your front end will slide a bit, what we call a 'drift' or a ‘push’ because that is exactly what it feels like; kind of like dragging a pencil eraser across a piece of paper. You do not need to do anything differently. All that will happen is that you will go a little wider in the corner than you had intended. Traction will come back all on its own and it is important that you do not tense up or do anything other than continue on your way.

Smile at your good fortune and expert skill, go back into the pits to change your underwear, and revel in your most recent exercise in experiencing physics first hand ;-)
 
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#2 · (Edited)
Is this the same as having the front tire "push"? Sliding the front tire past the traction limit?

Edit: nvm, obviously that's what you wrote!

PainfullySlo, the part where you wrote about increasing lean angle. What if you were already at max lean angle? Couldn't you increase your turn speed by turning the bike faster instead of adding lean angle?
 
#3 ·
PainfullySlo, the part where you wrote about increasing lean angle. What if you were already at max lean angle? Couldn't you increase your turn speed by turning the bike faster instead of adding lean angle?
I am not sure exactly what you mean by this. Do you mean a faster tip-in? The time it takes to go from straight up and down to your maximum lean?

A rider will almost always want to get to his ideal lean angle as quickly as possible. That will not allow for more speed but it will allow for a tighter line/trajectory,which can save you time in terms of how much track you are actually riding...but it will not increase your actual speed.

Anyway, the point of this writing was to discuss how a rider can learn to find the limits of front end traction. Speed is a by-product of knowing just how much traction you have available.
 
#4 ·
Make sure that your tip-in is at the same place as step 1. Our natural tendency is to tip in earlier to account for the additional speed.
I was fighting this tendency all weekend! I am being told that I am rushing the corner entry. My entry on to the main straight has been getting better, and I am getting a bit braver at holding on the gas on the main straight. The result of this has been about 10mph more at the end of the main straight.

Then I get all freaked out and mess the turn at the end of the straight all up. This must have something to do with wanting to tip in too soon.

Thanks for the insight!
 
#14 ·
Which track are you talking about? I ask since I've ridden LVMS "Classic Course" (road course outside the main stadium). That main straight is pretty short. :D The back straight though.... BRAAAAAAAAAPPP!
 
#6 ·
That actually answers my question contrasting your statement of 'No Bar Input' v my experience of correcting mid-corner on the street all the time. Answer: I am not using anywhere near all my front end traction or max lean angle.

PainfullySlo said:
This is where your proper body position comes into play. You are light on the bars and can feel the feedback coming from the front tire. Are you able to move the bars?

WAIT!!??!? Move the bars? But you said that mid-corner bar input is bad! Yep, I sure did and normally, it is bad. Adding bar input on top of the cornering forces places a tremendous load on your front tire and is the #1 reason for mid-corner crashes so we must use caution while we proceed. I am talking about adding the slightest amount of bar pressure, the kind of pressure you use when typing on a keyboard or on your phone. One or two pounds of pressure, nothing more.

If you are not yet at the limit, the bike will tip in a little bit further. Make a note of this for your next lap and try to get to this new lean angle as you go through. Repeat steps 1-2 until…

3) Eventually, you will put that slight pressure on the bars and they will ‘push back’. There will be resistance rather than the bike wanting to tip in further. This is often referred to as ‘feeling heavy’ as the bike really doesn’t want to do anything. As soon as you feel that resistance you must immediately release all bar pressure
 
#8 ·
Great write up man. *tips hat*.

This limit of traction is exactly what all racers are trying to ride along. If you listen to any of the MotoGP riders in their testing or practices it's all about "finding more grip" combined with good feedback from the front end. Grip is the key to everything that we do on these things.

These are very good tips for practicing. I'll have to remember to use them this month when I ride Laguna Seca for the first time.
 
#10 ·
I'm constantly reminding myself as I take almost every corner at the Island, light on the bars, late turn in, less brakes, more pace.
You're on the money about the fighting the early turn in urge, I notice that if I carry more pace into say turn 1, which is no brakes and down 1 gear to 5th, I REALLY have to fight that urge because the difference in an extra 10kmh is damn scary!
 
#13 ·
The apex is the slowest part of the turn.
Not usually. Depends on a lot of factors, but generally speaking a later apex is desirable, especially before a straight as it allows for a higher top speed on the straight. With a later apex, you are usually starting to accelerate already, so the speed will higher than the slowest part of the turn. This is a technique that is not usually used if there is risk of being passed by another vehicle as the second vehicle can use wide turn in as an opportunity to dive underneath the 1st car setting up a pass.

If you happen to go past the limit, your front end will slide a bit, what we call a 'drift' or a ‘push’ because that is exactly what it feels like; kind of like dragging a pencil eraser across a piece of paper. You do not need to do anything differently. All that will happen is that you will go a little wider in the corner than you had intended. Traction will come back all on its own and it is important that you do not tense up or do anything other than continue on your way.
Front end push (understeer) is certainly a possible outcome, but its also possible to be set-up for or induce oversteer. See the video in the link below; it has some examples of oversteer, but the video is not dedicated to it...Its worth watching either way though.

https://www.facebook.com/1465154370382475/videos/1716593635238546/

I'm going to expand on this "slush fund" you speak of. The graph below shows what traction looks like between a typical passenger car tire and a race tire when plotting friction vs slip angle. Both plots clearly show a plateau that is relatively flat. This indicates there is some slip allowed where traction doesn't drop off. The race tire shows a much more narrow window which means there is less room for error. Ideally though, you would want to be right at the left side of the plateau. Going further to the right on the plot provides no additional grip but generates more heat and wear. However, circumstances aren't always ideal and if the suspension isn't set up perfectly for every turn, you are not likely to be able to be right at the ideal point for both tires. Due to this imbalance, its likely you will have to try and push one tire's slip angle further to the right to bring the other tire up to the plateau. A poorly set-up suspension may not allow both tires to reach the plateau with both tires simultaneously.

 
#17 · (Edited)
Not usually. Depends on a lot of factors, but generally speaking a later apex is desirable, especially before a straight as it allows for a higher top speed on the straight. With a later apex, you are usually starting to accelerate already, so the speed will higher than the slowest part of the turn. This is a technique that is not usually used if there is risk of being passed by another vehicle as the second vehicle can use wide turn in as an opportunity to dive underneath the 1st car setting up a pass.
I think maybe there is some misunderstanding about the term 'apex'. I am speaking of your personal apex in the turn and not the physical mid-way point on a radius. Whether that be an early or late apex is not relevant for this point of discussion. The riders apex...the part of the turn where they are carrying the maximum lean and want to devote 100% traction to cornering forces (vs acceleration or braking forces) is by it's very definition the slowest part of any turn.

I apologize if that was not completely clear in my writing.

Riding Laguna in 2 weeks! BOOM!
MUCH HATE! :p
 
#16 ·
CSS is totally worth it. You could save a bundle of money though and use your own bike and just do the level one class. You'll learn SO MUCH that first day that you'll be glad you didn't pay for the 2-day course. Then take level 2 later down the road after some track days. :D

I was there at WSBK this year! I didn't get to watch much racing though :( I was busy "working".

Riding Laguna in 2 weeks! BOOM!
 
#30 ·
Also, because you are struggling with taking in and understanding the whole picture I'm going to take 1 specific thing you said and explain why it is wrong. "A late apex line is really just an artificially created increasing radius turn.". That is literally the opposite of what you are doing. Lets break it down into points through a corner:

1. Just beginning to tip into the corner- Speed=x1 ; Lean angle=y1
2. A couple feet later- x2<x1 ; y2>y1 (Your speed has decreased and lean angle increased)
3. A few more feet later- x3<x2 ; y3>y2
4. At the apex- x4<x3 ; y4>y3

QUIZ TIME!
If you decrease your speed in a turn what happens? A: The radius of your turn decreases.
What happens if you increase your lean angle in a turn? A: The radius of your turn decreases.

SO... that means your are carving a a decreasing radius arc down to the apex which is the opposite of an increasing radius. After the apex, once you are accelerating, now your arc is increasing. And if you are at all still skeptical, just watch that video until it clicks.
 
#33 ·
Also, because you are struggling with taking in and understanding the whole picture I'm going to take 1 specific thing you said and explain why it is wrong. "A late apex line is really just an artificially created increasing radius turn.". That is literally the opposite of what you are doing. Lets break it down into points through a corner:

1. Just beginning to tip into the corner- Speed=x1 ; Lean angle=y1
2. A couple feet later- x2<x1 ; y2>y1 (Your speed has decreased and lean angle increased)
3. A few more feet later- x3<x2 ; y3>y2
4. At the apex- x4<x3 ; y4>y3
Please provide the basis of this. All you've done is stated what you've been saying in a more mathematical form. Its arbitrary without an actual analysis.

QUIZ TIME!
If you decrease your speed in a turn what happens? A: The radius of your turn decreases.
What happens if you increase your lean angle in a turn? A: The radius of your turn decreases.

SO... that means your are carving a a decreasing radius arc down to the apex which is the opposite of an increasing radius. After the apex, once you are accelerating, now your arc is increasing. And if you are at all still skeptical, just watch that video until it clicks.
Take a look at the attached photo. I took a suggested late apex line that I found on google and plotted points on it and used a spline feature to plot the entire line. Its got its limitations, but for the purpose of this analysis, it shows my point clearly. Using an evaluation tool, I had it show the curvature. The series of lines perpendicular to the curve represent its curvature at that point, where the longer lines represent a greater amount of curvature (tighter radius) and the shorter lines represent a larger radius. Its very clear that the tightest radius occurs early in the turn and gradually straightens out from there. To make the best use of the friction circle, the rider/driver would have to add throttle as that radius increases. It would be done so gradually to try and maintain 100% use of the friction circle.
 

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#34 ·
I give up. I hope that others find this less confusing than you apparently do.
 
#41 ·
This has nothing to do with him finding it confusing, is has to do with cornering though - Have you tried the "fastest lap calculator"? And in that case, what do you think of it? Thinking of buying it, i just dont know if its really worth it.
 
#35 ·
Great write up Slo,

This is what I've been trying to work for the last few trackdays. I still find myself having to think about staying loose on the bars and that doesn't help with my communication with the front end.

"Apex" I feel like it has taken over this very informative post. The apex is relative to the line you are taking. Maybe CK has enough money to ride on the track alone, he doesn't have lap traffic or anyone trying to pass him. He has the luxury to take the same line, hit the same brake marker every time, and never have to alter his apex.
 
#36 ·
The apex or clipping point is the innermost point of the line taken through a curve. The apex is often, but not always, the geometric center of the turn.

Within the context of motorcycling, the apex refers to the point where the motorcycle is closest to the inside of the corner and not necessarily the center of the corner. Because motorcycles need to lean through corners and the risk associated with the lean, it is desirable to limit the time leaning over as much as possible; as such it is a popular technique to delay the apex until some point in the second half of the turn.

https://en.wikipedia.org/wiki/Racing_line

According to the Wikipedia, the apex can move. lolwut.
 
#42 ·
Let me just interject with something.

There are more than one line through any turn. Because there are multiple lines through any given turn there are also multiple apexes to any given turn.

True... the defined "apex" of a turn on paper would be the mid point of the arc of the turn. But that arc can change. So in my mind the apex is always defined by the rider at the time while negotiating that turn.

When setting up track days we place a cone at the preferred apex of every turn to give people a clear visual. I can tell you that almost never is that cone placed directly on the mid point of the main arc of that turn (assumed you're looking at it from above)... it's placed at the apex of the turn. :D
 
#47 ·
Hello,

Just here to say thanks, i read the article on page 1 and aplyied on the track this past weekend. (Monteblanco Spain)

I´m on my first year riding so i´m slow.

Softer on the brakes and closed my lines a bit. Manage to get my laps 5 seconds below my previous lap record , much more consistent and manage to get several laps below the 1:59 mark wich was impossible one month ago.

Will keep reading everything on this forum. :bigthumb:

Thanks for your input.

Will put a video link later on.
 

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#55 ·
CKwik, I absolutely get what you're saying. You can turn sharply before the apex, and get on the throttle as your line flattens out, putting the closest point of the turn (the apex) at somewhere other than the slowest point of the turn.

Initially I took critique with you saying the apex does not move. I believe it does.
 
#58 ·
BUMP for the start of track season =) Unless you are in a place where you can ride track already, or all year...in which case you have earned my dislike :p
 
#63 ·
Yeah, podcast would be awesome (I'd listen too). Damnit the days are getting shorter so I feel whilst your season is ramping up mine is going to end soon. Hoping for an Indian Summer...
 
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