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This is normally about the time that people start debating where the term "trail braking" comes from and what "trail braking" is. One school of thought is that it is simply a reference to "trailing" off the brake through the entry of the corner to some point selected by the rider. The other is that you brake into the corner shifting weight to the front end and decrease the "trail" of the front suspension by compressing it, thereby shortening the wheelbase and facilitating turning. In the latter you want to trail all the way to the tightest point in the turn so that the bike is most agile when agility is most needed. I have no idea what the genuine origin of the term is.
 

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Based on this graphic there is a gap between braking and accelerating. Essentially once you have finished turning you should be coming off the brakes, coasting while holding the line, then accelerating as you exit. Is that accurate?
No. It typically takes about 25% throttle to get a bike to stop slowing down from cornering friction. See data screenshot attached.

BTW: That's the difference between actually looking at data and going past superficial understanding of what's happening with the bike. The bike does not speed up the moment you touch the throttle. So many clowns pass around data about riding when they really have no real clue (not saying you, just generally many people think they know what's up. They don't. I'd say at CSS we understand about 40% of all the key aspects of motorcycle riding. There's so much more to understand...
 

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This is normally about the time that people start debating where the term "trail braking" comes from and what "trail braking" is. One school of thought is that it is simply a reference to "trailing" off the brake through the entry of the corner to some point selected by the rider. The other is that you brake into the corner shifting weight to the front end and decrease the "trail" of the front suspension by compressing it, thereby shortening the wheelbase and facilitating turning. In the latter you want to trail all the way to the tightest point in the turn so that the bike is most agile when agility is most needed. I have no idea what the genuine origin of the term is.
The "trail" part just refers to the tapering off of brake pressure coming into the corner. Trail braking was a car racing term long before the motorcycle community started using it, so the mechanical trail dimension of the front end of a motorcycle had nothing to do with where the term initiated.
 

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No. It typically takes about 25% throttle to get a bike to stop slowing down from cornering friction. See data screenshot attached.

BTW: That's the difference between actually looking at data and going past superficial understanding of what's happening with the bike. The bike does not speed up the moment you touch the throttle. So many clowns pass around data about riding when they really have no real clue (not saying you, just generally many people think they know what's up. They don't. I'd say at CSS we understand about 40% of all the key aspects of motorcycle riding. There's so much more to understand...
Yes, but, for example when I am riding on a slow corner (50kmh), it takes about 0.3-0.4 seconds (4.2-5.6 meters) to actually accelerate after getting on the throttle, and in fast corners (150kmh) 0.6-0.7 seconds (25.0-29.2 meters).

And if we think about a average track day rider, for him things are a lot easyer if he do not touch the throttle before apex, and rolls/uses engine brake until apex.
Especially because a very typical error for a average track day rider is that he totally ****s up hes line before apex, and then tries to fix things with throttle, and then really ****s up (wrong line -> maximum lean angle + cranking throttle), and if he is lucky he does not low- or hi-side (DTC is golden in this case).
And then he just repeats this totally ****ed up action in every corner, every lap, every track day, and thinks "My Line Is Fine", because lap times are improving.

But if you are a really fast rider, only a couple/few seconds off the track record, then those decimals are significant. And the fast rider probably also has skill and capacity, and a need, for that kind of finesse.

"Cornering friction" vs engine brake? I would guess that most of the about 25% throttle (grip) goes to eliminate engine brake.
And is the graph from a s1k? In that case what is the actual throttle valve positions?
 

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"Cornering friction" vs engine brake? I would guess that most of the about 25% throttle (grip) goes to eliminate engine brake. And is the graph from a s1k? In that case what is the actual throttle valve positions?
Cornering friction is common among all bikes, the engine braking can vary a lot from a big twin to a multi to a 2 stroke, etc. But we have cornering friction, engine braking, wind resistance (would of course be greater in a high speed turn). Other variables would be elevation and camber of the turn, lean angle, type of tires, size of tires, etc.

Seems you are talking about engine braking (closed throttle grip) and what small percent the valve position remains open--I'm talking about the bike still slowing down despite the throttle grip and valves being opened, so engine braking would not be a factor here in this specific graph and the point being made.
 

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Cornering friction is common among all bikes, the engine braking can vary a lot from a big twin to a multi to a 2 stroke, etc. But we have cornering friction, engine braking, wind resistance (would of course be greater in a high speed turn). Other variables would be elevation and camber of the turn, lean angle, type of tires, size of tires, etc.

Seems you are talking about engine braking (closed throttle grip) and what small percent the valve position remains open--I'm talking about the bike still slowing down despite the throttle grip and valves being opened, so engine braking would not be a factor here in this specific graph and the point being made.
Well, lets put it this way, I'm talking about the bike still slowing down despite the throttle grip and valves being opened, grip position is 26-29-28, what is the throttle valve position in those points?
 

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Here is some values from my data/
Grip% vs Throttle valve%, when bike actually starts to accelerate out of the turn.

26-13
26-11
20-8
34-18
17-5
24-13
23-9
29-11
18-9
21-7
 

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I looked for that exact screen shot and was not able to find it so I went to another national level racer and got these:

Point of actually speeding up:
Grip/Valve
61/44 (fast corner)
45/22
43/20
43/20
51/30

This is going to have a lot to do with lean angle and spin% in which case the more extreme level of rider is going to have more interference vs a mid level trackday rider. DTC settings and type of corner pay big as well. Bottom line is gas on does not equal bike immediately speeds up, which is why the graphic of the different cornering forces, though counter-intuitive to some people, is more technically accurate as to what's happening in a corner.
 

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I looked for that exact screen shot and was not able to find it so I went to another national level racer and got these:

Point of actually speeding up:
Grip/Valve
61/44 (fast corner)
45/22
43/20
43/20
51/30

This is going to have a lot to do with lean angle and spin% in which case the more extreme level of rider is going to have more interference vs a mid level trackday rider. DTC settings and type of corner pay big as well. Bottom line is gas on does not equal bike immediately speeds up, which is why the graphic of the different cornering forces, though counter-intuitive to some people, is more technically accurate as to what's happening in a corner.
The fastest turn what I could find from different datas was V_Rear 168 kmh, and Grip_pos 40%/ Throttle valve 29%, when bike starts to accelerate.

What was the speed in that 61/44 corner?

Term "cornering friction" is still totally stupid term, because most of the deceleration is usually caused by engine brake after braking. And then there is air drag (very signifigant only in very fast corners), and rolling resistance.

So when you start to apply throttle, you are not fighting against "cornering friction" , you are just mainly makeing engine brake smaller.

That is why that graphic of the different cornering forces is quite misleading and imperfect.
 

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So, what's the difference to you between cornering friction and rolling resistance? And how can engine braking be a factor if the throttle is being opened and the bike is still slowing down?

You seem like a very bright and knowledgeable guy, but your desire to establish a heightened level of authority and credibility is leading things, again, into a semantics discussion. Or maybe you figure by getting into a debate you can learn something you did not know, or modify an existing notion. I get that. Sometimes that's the best way to learn.

Tomorrow I leave on a 3 1/2 week tour so I'm not going to be able to engage at my desktop like I have recently.
 

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The cornering friction Dylan has identified is both real and substantial if a vehicle is cornering at any real speed.

A vehicle turns because there is a net horizontal net force acting upon it. This is the horizontal friction force, or cornering friction, which turns the vehicle. This is centripetal force, pointing toward the center of the turn. In a car, you feel thrown to the outside of the corner, and the car leans to the outside, due to your inertia wanting to continue straight.

Each time your speed doubles, this force is four times greater. Or, put another way, if the horizontal friction/cornering friction remains constant and you are at maximum adhesion, doubling your speed requires a curve with four times the radius.

If you are cornering slowly, engine braking will be greater than cornering friction. However, once you are cornering at any significant speed, this horizontal friction force is large and takes a good amount of engine power to overcome. Engine braking is a small force in comparison.
 

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The cornering friction Dylan has identified is both real and substantial if a vehicle is cornering at any real speed.

A vehicle turns because there is a net horizontal net force acting upon it. This is the horizontal friction force, or cornering friction, which turns the vehicle. This is centripetal force, pointing toward the center of the turn. In a car, you feel thrown to the outside of the corner, and the car leans to the outside, due to your inertia wanting to continue straight.

Each time your speed doubles, this force is four times greater. Or, put another way, if the horizontal friction/cornering friction remains constant and you are at maximum adhesion, doubling your speed requires a curve with four times the radius.

If you are cornering slowly, engine braking will be greater than cornering friction. However, once you are cornering at any significant speed, this horizontal friction force is large and takes a good amount of engine power to overcome. Engine braking is a small force in comparison.
Great explanation @Elk thank you :)

I thought that the tire size difference between zero lean and maximum lean was why I needed to apply more throttle to maintain speed. Now I see there are additional components, with rolling resistance / cornering friction being one of the biggest.

:smile2::nerd: I love learning
 

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This is also why stickier tires or a more aggressive track surface allow one to corner faster. With an increased coefficient of friction, the bike can produce greater horizontal friction/cornering friction while remaining on the road.

A fun way to play with this is to turn cruise control on at highway speed and dive into a corner you know well and can play on safely. The bike first slows down and then speeds up again as the cruise control adds throttle. It is quite pronounced in a significant corner. (Yes, this is borderline stupid but it still amuses me.)
 

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This is also why stickier tires or a more aggressive track surface allow one to corner faster. With an increased coefficient of friction, the bike can produce greater horizontal friction/cornering friction while remaining on the road.

A fun way to play with this is to turn cruise control on at highway speed and dive into a corner you know well and can play on safely. The bike first slows down and then speeds up again as the cruise control adds throttle. It is quite pronounced in a significant corner. (Yes, this is borderline stupid but it still amuses me.)
I do this, but with no hands >:) @Outta Control was there on a road trip, and I also do it turn 2 at Thunderhill

It doesnt feel like it gets back up to speed even though the indicated shows as much. Could this me from tire circumference difference at lean? Or is it in my head?
 

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So, what's the difference to you between cornering friction and rolling resistance? And how can engine braking be a factor if the throttle is being opened and the bike is still slowing down?

You seem like a very bright and knowledgeable guy, but your desire to establish a heightened level of authority and credibility is leading things, again, into a semantics discussion. Or maybe you figure by getting into a debate you can learn something you did not know, or modify an existing notion. I get that. Sometimes that's the best way to learn.

Tomorrow I leave on a 3 1/2 week tour so I'm not going to be able to engage at my desktop like I have recently.
Earlier you said:
It typically takes about 25% throttle to get a bike to stop slowing down from cornering friction.
That is totally misleading, even a false statement.

I'm not even sure if you understand that engine brake is not on-off kind of thing which magically disappears when you twist throttle grip by 1 %.

In a average corner, as I said, most of the about 25% throttle (grip) goes to eliminate engine brake.
Then air drag.
Then rolling resistance.
Those all are also present when you are riding upright.
And yes also a very small amout goes to eliminate "cornering friction". Because cornering friction is mainly lateral force, not longitudinal force.

If you want you can also test how much is the cornering fricition in reality.

First find a long flat turn, pull the clutch before you turn in to the turn.
Then do the same entry speed on a flat straight, and pull the clutch.
And then compaire deceleration values of those two cases.
 

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If you are cornering slowly, engine braking will be greater than cornering friction. However, once you are cornering at any significant speed, this horizontal friction force is large and takes a good amount of engine power to overcome. Engine braking is a small force in comparison.
In high speed corners air drag or engine brake is the biggest force.
And the longitudinal vector of the cornering friction is still quite small.
 

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In high speed corners air drag or engine brake is the biggest force.
And the longitudinal vector of the cornering friction is still quite small.
Can you further explain air drag and engine brake? To me engine brake is amount of deceleration when throttle is closed, I didn’t think there is any engine brake after throttle is opened 1%
 

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. . . the longitudinal vector of the cornering friction is still quite small.
Unfortunately, no. The centripetal force which must be produced for a vehicle to corner is substantial. This is the force we are counteracting by leaning the bike. It is the force which is greatly diminished when transversing a banked corner v. no banking. It is equal to the inertial which wants to throw you off of the track, makes your body in a car slide to the outside, makes a car lean hard to the outside.

Consider, as a simile, straight line acceleration. To equal 1g of acceleration, a vehicle needs to run 0-60 MPH in 2.74 seconds. The S1000RR, in the correct hands, is capable of this using its full 199hp. Now consider, a cornering force of 1g. While not directly comparable, it takes considerable energy to drive a vehicle around a corner at 1g. This is because one is continually accelerating in a new direction toward the inside of the corner. This takes a lot of energy.

Again, this is not perceived as a major factor until one is cornering hard - as you should be doing on the track. In a car on a leisurely drive, one does not feel thrown to the outside of a corner. But in a high speed corner taken hard, the forces are pronounced and can be quite violent.

Also, regarding engine braking, engine braking produced by an in-line four is relatively small, even smaller on the S1000RR in slick mode with its increased fuel overrun. The smallest throttle opening cancels engine braking as all is required is sufficient fuel to keep the engine spinning. The bike will quickly slow down regardless - pull in the clutch on a straight away at speed and the bike slows rapidly. Drag is the biggest culprit in slowing the bike in a straight away. Drag and cornering friction are the two biggest in high speed corners.
 
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