Trail-braking and accelerating in corners-

[Shibumi]

Tell me if this is correct cornering science-

According to the picture below, the arc of travel intersects the radius of a smaller circle for a period of time during traverse of a corner. During that intersection, let's say a perfect execution puts the bike at 100% of the limit of traction. So while the bike is at full lean neither additional brake or throttle can be applied, or it will break traction and go down.

So during the braking phase, brakes can be applied at 100% of traction limit until the bike begins to lean, after which braking must gradually decrease until the point of maximum lean and traction is reached.

Then after the smaller radius and the arc of travel begin to separate, throttle can be applied gradually until 100% is reached as bike approaches straight up.


Correct?

 

[OZZY]

 

[rubber2burn]

What Picture???

 

[PR111]

Depends on the corner and the bike. For the 90 degree corner you show, for a big motored bike, that is the theoretical ideal. Smaller bikes use high-corner speeds to make time so they wouldn't be braking to the apex. Just thinking out loud.

PR

 

[BA BUSA]

Aaah yeah I guess  

There is a fine line where you have to be OFF the gas or brakes in a corner...we as street riders don't usually have that high of a corner speed to worry about "trail braking"

It is usually being to abrupt on the brakes or gas when we get in trouble.

Try doing about 80-90% of your braking before your turn in to set the suspension...then with one or two fingers on the front lever keep some pressure on to keep the bike tracking. As you approach
the apex of the turn you easy off the brakes and start to easy into the throttle  

 

[Charlesbusa]

(Shibumi @ Sep. 09 2007,19:06) Tell me if this is correct cornering science-

Let's say a perfect execution puts the bike at 100% of the limit of traction. So while the bike is at full lean neither additional brake or throttle can be applied, or it will break traction and go down.

So during the braking phase, brakes can be applied at 100% of traction limit until the bike begins to lean, after which braking must gradually decrease until the point of maximum lean and traction is reached.

Then throttle can be applied gradually until 100% is reached as bike approaches straight up.


Correct?  

You are correct.  You can use 100% braking or acceleration when straight-up and down, and 100% cornering at full lean.  When at partial lean, you have to use partial percentages of braking/accel and cornering that add up to equal to or less than 100%.

Using more than 100% of the tire's grip will lead to the tire locking up, sliding, or spinning up.  Resulting in for most of us in a crash  

Other things to consider.

No abrupt changes in chasis movement.  Trail braking compresses the front suspension, front is compressed while the rear is uncompressed.  As you start to lean and gradual lessen the amount of braking, the cornering forces replace the braking forces keeping the front suspension compressed and gradually compress the rear shock.  Keeping the chasis stable by gradually releasing the brake and gradually compressing the shock allow the tires to maintain grip.  An abrupt chasis movement(like letting go of the front brake all at once) while cause the tires to loose grip.  At full lean the cornering forces are solely compressing the front and rear suspension, bike is equally compressed.  As the bike starts to stand up the front suspension uncompresses while the rider adds throttle to keep the rear shock compressed.  Once straight up and down, the front is totally uncompressed and the rear is compressed.  Again, a smooth slow compression and uncompression of suspension allows the tires to maintain grip.  An abrupt chasis movement(like hammering the throttle all at once) will cause the tires to loose grip.

Adding weight(force) to the tires increases grip.  The more weight(force) you transfer to a tire the more grip that tire gives you.  Rest your hand on your desk and try to move it sideways.  Now PRESS your hand firmly onto the desk and try to move it sideways.  It takes much more force to move your hand sideways when you add weight(downforce) than if you just rest it.  Same thing with tires.  
Also the extra force causes the tire to deform at the contact patch making the contact patch larger than when no extra force is added to the tire.  Braking forces cause the front tire to deform.  Acceleration forces cause the rear tire to deform.  And cornerning forces cause both tires to deform.

You, me, and 90% of racers will never maintain 100% of the tire's grip because of the amount of skill required to do this.  Only the very top level riders can consistantly use 100% of their tire's grip, but even then they still crash.  It isn't worth crashing over  

 

[Shibumi]

(Charlesbusa @ Sep. 09 2007,23:54)

(Shibumi @ Sep. 09 2007,19:06) Tell me if this is correct cornering science-

Let's say a perfect execution puts the bike at 100% of the limit of traction. So while the bike is at full lean neither additional brake or throttle can be applied, or it will break traction and go down.

So during the braking phase, brakes can be applied at 100% of traction limit until the bike begins to lean, after which braking must gradually decrease until the point of maximum lean and traction is reached.

Then throttle can be applied gradually until 100% is reached as bike approaches straight up.


Correct?

You are correct. You can use 100% braking or acceleration when straight-up and down, and 100% cornering at full lean. When at partial lean, you have to use partial percentages of braking/accel and cornering that add up to equal to or less than 100%.

Using more than 100% of the tire's grip will lead to the tire locking up, sliding, or spinning up. Resulting in for most of us in a crash

Other things to consider.

No abrupt changes in chasis movement. Trail braking compresses the front suspension, front is compressed while the rear is uncompressed. As you start to lean and gradual lessen the amount of braking, the cornering forces replace the braking forces keeping the front suspension compressed and gradually compress the rear shock. Keeping the chasis stable by gradually releasing the brake and gradually compressing the shock allow the tires to maintain grip. An abrupt chasis movement(like letting go of the front brake all at once) while cause the tires to loose grip. At full lean the cornering forces are solely compressing the front and rear suspension, bike is equally compressed. As the bike starts to stand up the front suspension uncompresses while the rider adds throttle to keep the rear shock compressed. Once straight up and down, the front is totally uncompressed and the rear is compressed. Again, a smooth slow compression and uncompression of suspension allows the tires to maintain grip. An abrupt chasis movement(like hammering the throttle all at once) will cause the tires to loose grip.

Adding weight(force) to the tires increases grip. The more weight(force) you transfer to a tire the more grip that tire gives you. Rest your hand on your desk and try to move it sideways. Now PRESS your hand firmly onto the desk and try to move it sideways. It takes much more force to move your hand sideways when you add weight(downforce) than if you just rest it. Same thing with tires.
Also the extra force causes the tire to deform at the contact patch making the contact patch larger than when no extra force is added to the tire. Braking forces cause the front tire to deform. Acceleration forces cause the rear tire to deform. And cornerning forces cause both tires to deform.

You, me, and 90% of racers will never maintain 100% of the tire's grip because of the amount of skill required to do this. Only the very top level riders can consistantly use 100% of their tire's grip, but even then they still crash. It isn't worth crashing over

Cool!

Hey Charles, you are also a petite white boy, let's compare notes. I'm running 32-33 PSI on my Qualifiers, anything more feels jittery and bouncy. How about you? And what are your current suspension settings preload/comp/rebound?


P.S.- Gotta confess, I actually washed my Bus a few days ago!

It was to friggin hot to ride...

P.P.S.- Roger that on the top riders- I'm thinking someone like Rossi is probably able to run 99-100% for an entire race. Just imagine the touch needed to keep in that range through braking, maintenance throttle, and acceleration corner after corner after corner...

Brings to mind a race I saw Rossi win, the last corner he cooked the tire off all the way through just spinning and smoking to give the fans a show!! Imagine the skill and the sheer arrogance to do that with the stakes at hand in a MotoGP race...

 

[bigoltool]

(Shibumi @ Sep. 10 2007,19:32)

(Charlesbusa @ Sep. 09 2007,23:54)

(Shibumi @ Sep. 09 2007,19:06) Tell me if this is correct cornering science-

Let's say a perfect execution puts the bike at 100% of the limit of traction. So while the bike is at full lean neither additional brake or throttle can be applied, or it will break traction and go down.

So during the braking phase, brakes can be applied at 100% of traction limit until the bike begins to lean, after which braking must gradually decrease until the point of maximum lean and traction is reached.

Then throttle can be applied gradually until 100% is reached as bike approaches straight up.


Correct?

You are correct. You can use 100% braking or acceleration when straight-up and down, and 100% cornering at full lean. When at partial lean, you have to use partial percentages of braking/accel and cornering that add up to equal to or less than 100%.

Using more than 100% of the tire's grip will lead to the tire locking up, sliding, or spinning up. Resulting in for most of us in a crash

Other things to consider.

No abrupt changes in chasis movement. Trail braking compresses the front suspension, front is compressed while the rear is uncompressed. As you start to lean and gradual lessen the amount of braking, the cornering forces replace the braking forces keeping the front suspension compressed and gradually compress the rear shock. Keeping the chasis stable by gradually releasing the brake and gradually compressing the shock allow the tires to maintain grip. An abrupt chasis movement(like letting go of the front brake all at once) while cause the tires to loose grip. At full lean the cornering forces are solely compressing the front and rear suspension, bike is equally compressed. As the bike starts to stand up the front suspension uncompresses while the rider adds throttle to keep the rear shock compressed. Once straight up and down, the front is totally uncompressed and the rear is compressed. Again, a smooth slow compression and uncompression of suspension allows the tires to maintain grip. An abrupt chasis movement(like hammering the throttle all at once) will cause the tires to loose grip.

Adding weight(force) to the tires increases grip. The more weight(force) you transfer to a tire the more grip that tire gives you. Rest your hand on your desk and try to move it sideways. Now PRESS your hand firmly onto the desk and try to move it sideways. It takes much more force to move your hand sideways when you add weight(downforce) than if you just rest it. Same thing with tires.
Also the extra force causes the tire to deform at the contact patch making the contact patch larger than when no extra force is added to the tire. Braking forces cause the front tire to deform. Acceleration forces cause the rear tire to deform. And cornerning forces cause both tires to deform.

You, me, and 90% of racers will never maintain 100% of the tire's grip because of the amount of skill required to do this. Only the very top level riders can consistantly use 100% of their tire's grip, but even then they still crash. It isn't worth crashing over

Cool!

Hey Charles, you are also a petite white boy, let's compare notes. I'm running 32-33 PSI on my Qualifiers, anything more feels jittery and bouncy. How about you? And what are your current suspension settings preload/comp/rebound?


P.S.- Gotta confess, I actually washed my Bus a few days ago!

It was to friggin hot to ride...

P.P.S.- Roger that on the top riders- I'm thinking someone like Rossi is probably able to run 99-100% for an entire race. Just imagine the touch needed to keep in that range through braking, maintenance throttle, and acceleration corner after corner after corner...

Brings to mind a race I saw Rossi win, the last corner he cooked the tire off all the way through just spinning and smoking to give the fans a show!! Imagine the skill and the sheer arrogance to do that with the stakes at hand in a MotoGP race...

In theory you can't go to 100% of the available traction limit all race long. The top racers try to choose tires that will allow them to go as long and hard as they need to, to follow there race strategy, if one exists. If rider X tries to go all out all race long he stands to cook his tires and get passed at the end by racer Y who saved a little for later in the race. In a perfect world you would want a tire that "goes off" as little as possible over race distance and no more. So teams try to find tires that allow consistently fast times lap after lap rather than one that sticks really well for ten laps and then goes south or flip it to a really hard tire that may not allow you go as fast as the other guys in the early stages of the race. The teams rely heavily on rider data and input to make tire selections before the race, which is a big reason the top guys get paid what they get. To give all necessary feedback to the engineers so they can make a proper set up selections. Then it as all up to the rider to precisely meter out everything the bike has over race distance to get the best result.

 

[Ononewheel]

(Shibumi @ Sep. 09 2007,19:06) Tell me if this is correct cornering science-

According to the picture below, the arc of travel intersects the radius of a smaller circle for a period of time during traverse of a corner. During that intersection, let's say a perfect execution puts the bike at 100% of the limit of traction. So while the bike is at full lean neither additional brake or throttle can be applied, or it will break traction and go down.

So during the braking phase, brakes can be applied at 100% of traction limit until the bike begins to lean, after which braking must gradually decrease until the point of maximum lean and traction is reached.

Then after the smaller radius and the arc of travel begin to separate, throttle can be applied gradually until 100% is reached as bike approaches straight up.


Correct?

You have the right idea.

You would be surprised however just how much speed you can scrub off with the front tire alone.

You need to hit up Frank Kinsey's racing school. The no brakes drill will do wonders for you turn in, and show you just how fast you can come into a turn.

 

[Shibumi]

(Ononewheel @ Sep. 11 2007,07:44)

(Shibumi @ Sep. 09 2007,19:06) Tell me if this is correct cornering science-

According to the picture below, the arc of travel intersects the radius of a smaller circle for a period of time during traverse of a corner. During that intersection, let's say a perfect execution puts the bike at 100% of the limit of traction. So while the bike is at full lean neither additional brake or throttle can be applied, or it will break traction and go down.

So during the braking phase, brakes can be applied at 100% of traction limit until the bike begins to lean, after which braking must gradually decrease until the point of maximum lean and traction is reached.

Then after the smaller radius and the arc of travel begin to separate, throttle can be applied gradually until 100% is reached as bike approaches straight up.


Correct?

You have the right idea.

You would be surprised however just how much speed you can scrub off with the front tire alone.

You need to hit up Frank Kinsey's racing school. The no brakes drill will do wonders for you turn in, and show you just how fast you can come into a turn.

Where is Kinsey?

 

[Ononewheel]

http://www.kinseyracingschool.com/


He goes to roebling road near Savannah, Ga and Jennings GP in Fl.

For the price, its worth it. His classes are small so you will get some good time with him, he starts off with some race theory, and then starts doing sessions, you follow him and you are not allowed to use your brakes until the last session of the day. He focuses on picking the right line, smoothness, and corner speed. Its a fun day. Possibly the best part of the day is the walk around the track at lunch.

I know there are lots of good schools out there, but this is the only "school" I have done, and think very highly of it.

 

[Charlesbusa]

(Shibumi @ Sep. 10 2007,19:32) Hey Charles, you are also a petite white boy, let's compare notes. I'm running 32-33 PSI on my Qualifiers, anything more feels jittery and bouncy. How about you? And what are your current suspension settings preload/comp/rebound?

I'm running the BT002RS tires and like them a lot. What cold PSI I start with depends on how hot or cold the day is and the track is. But generally I start out with 32-33psi cold.

But then its all about hot psi for me. As soon as I get off the bike, I rip off my gloves/helmet/jacket, grab the air guage. And set my hot psi to 35psi front and back.

I have measured my tires after I have gotten back from trackdays and they tend to be at 30psi cold front and 28psi cold rear.

But I'll always start a little high on the next trackday, 32-33psi cold, becasue its always easier to take some out than to put some in

My front suspension isn't stock. Stock forks with Ohlins internals(.95springs). I don't remember my rear shock settings off hand, but I can figure them out if you want

 

[gtrpimp76]

(Ononewheel @ Sep. 11 2007,21:44) The no brakes drill will do wonders for you turn in, and show you just how fast you can come into a turn.

That's what Keith Code at CA Superbike school teaches.

 

[kennym4]

(Charlesbusa @ Sep. 12 2007,02:02)

(Shibumi @ Sep. 10 2007,19

) Hey Charles, you are also a petite white boy, let's compare notes. I'm running 32-33 PSI on my Qualifiers, anything more feels jittery and bouncy. How about you? And what are your current suspension settings preload/comp/rebound?

I'm running the BT002RS tires and like them a lot.  What cold PSI I start with depends on how hot or cold the day is and the track is.  But generally I start out with 32-33psi cold.

But then its all about hot psi for me.  As soon as I get off the bike, I rip off my gloves/helmet/jacket, grab the air guage.  And set my hot psi to 35psi front and back.

I have measured my tires after I have gotten back from trackdays and they tend to be at 30psi cold front and 28psi cold rear.  

But I'll always start a little high on the next trackday, 32-33psi cold, becasue its always easier to take some out than to put some in  

My front suspension isn't stock.  Stock forks with Ohlins internals(.95springs).  I don't remember my rear shock settings off hand, but I can figure them out if you want  

Not talking about going all out, pretending you're on a track, but what PSI do you run in the twisty's ? How does weight play into this ? Would I at 235 lbs. want my PSI to be the same as someone that's 185 lbs. ?

 

[kd185]

trail braking can be very tricky
ALL street riders will find them selves on the ground eventually trying to master trail braking
trail braking changes the feel when the bike takes a set in the turns
thats when the front suspension has relaxed enough and theres enough weight on the rear to start turning the throttle on

 

[MPH 200]

You need to do the majority of your braking prior to cornering, trail braking is hard to master. You want to stay on the gas to keep weight transferred to the rear tire throughout the corner. The natural tendency of the bike is to load the front after hard braking, this can cause a lowside. The good guys brake & accelerate simultaneously. Track riding only.

 

[JET-A]

According to "A Twist of the Wrist", the front and rear tires will reach 100% traction at different times unless the rider adds some input. Since the rear tire has 60% of the total contact patch, you want to have accomplished a weight transfer with the throttleto get 60% of the weight onto the rear. That is the point where both tires will *theoretically* reach 100% traction at the same time.

So, using that information, you should have begun the throttle roll-on prior to reaching the 100% point on the diagram.

I don't ride this hard, so I can only offer the theories I have read about, as I understand them.

Todd

 

[Charlesbusa]

(kennym4 @ Sep. 12 2007,02:26)

(Charlesbusa @ Sep. 12 2007,02:02)

(Shibumi @ Sep. 10 2007,19

) Hey Charles, you are also a petite white boy, let's compare notes. I'm running 32-33 PSI on my Qualifiers, anything more feels jittery and bouncy. How about you? And what are your current suspension settings preload/comp/rebound?

I'm running the BT002RS tires and like them a lot.  What cold PSI I start with depends on how hot or cold the day is and the track is.  But generally I start out with 32-33psi cold.

But then its all about hot psi for me.  As soon as I get off the bike, I rip off my gloves/helmet/jacket, grab the air guage.  And set my hot psi to 35psi front and back.

I have measured my tires after I have gotten back from trackdays and they tend to be at 30psi cold front and 28psi cold rear.  

But I'll always start a little high on the next trackday, 32-33psi cold, becasue its always easier to take some out than to put some in  

My front suspension isn't stock.  Stock forks with Ohlins internals(.95springs).  I don't remember my rear shock settings off hand, but I can figure them out if you want  

Not talking about going all out, pretending you're on a track, but what PSI do you run in the twisty's ? How does weight play into this ? Would I at 235 lbs. want my PSI to be the same as someone that's 185 lbs. ?

On the street I run 35/36 psi in my tires. Street riding doesn't put nearly the heat into tires the track riding does.

Weight does influence what PSI your tires need to be. As well as tire construction and many other variables.

PSI is something you have to play with and find out what works for you.

 

[Charlesbusa]

(JET-A @ Sep. 12 2007,06:30) According to "A Twist of the Wrist", the front and rear tires will reach 100% traction at different times unless the rider adds some input.  Since the rear tire has 60% of the total contact patch, you want to have accomplished a weight transfer with the throttleto get 60% of the weight onto the rear.  That is the point where both tires will *theoretically* reach 100% traction at the same time.

So, using that information, you should have begun the throttle roll-on prior to reaching the 100% point on the diagram.

I don't ride this hard, so I can only offer the theories I have read about, as I understand them.

Todd

Forgot to mention that

 

[gtrpimp76]

Trail braking shouldn't be used by the average street rider. All of the braking should be done prior to the corner.

But on the racetrack, it's a different story. One thing many racers point out is that you'll release the brake more gradually than you applied them going into the corner. It prevents the chassis from getting upset mid-corner and any chatter.