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Maximum Braking Effect


Jaybird180
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If I understood correctly, Keith says (TOTW1) that for a sportbike, front brake only will produce the shortest stopping distance. True/ False?

 

JB,

 

OK, there is a bit of data on this (I'm going to do it in pieces because as I tell my kids, I have a short attention span:), we get students all the time we go over this with them, but I'll start with the first piece--how much braking will the front brake do? In other words what is the potential that it can do on a modern sport bike, say anything made in the last 25 years?

 

CF

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If I understood correctly, Keith says (TOTW1) that for a sportbike, front brake only will produce the shortest stopping distance. True/ False?

 

Since you're asking about the shortest STOPPING distance I would say you need a combo of both front and back brakes. Initial rear brake to lower the rear and bring down the CG then the rest of the braking will all be on the front. Sportbikes have 2 brake calipers on the front for good reason. On the track you only need the front to scrub off some speed.

I never read TOTW1. Plan to though.

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If I understood correctly, Keith says (TOTW1) that for a sportbike, front brake only will produce the shortest stopping distance. True/ False?

 

Since you're asking about the shortest STOPPING distance I would say you need a combo of both front and back brakes. Initial rear brake to lower the rear and bring down the CG then the rest of the braking will all be on the front. Sportbikes have 2 brake calipers on the front for good reason. On the track you only need the front to scrub off some speed.

I never read TOTW1. Plan to though.

And those front brake rotors are much larger for a reason. They'll provide the bulk of your stopping power, and the heat needs to be dissipated as to avoid overheating.

 

My first trackday I was in the habit of using my rear brakes, and when I started overshooting on a straight, found myself pushing harder on the rear brake as a SR, possibly from my car. Instead of just overrunning the straight, I skid right off of it. They usually keep good communication on the track, and when I got off my beginner instructor came straight up to me and told me to stop using my rear brakes all together, and found that most riders out there don't use them. I haven't used them since and have had no negative outcomes as a result. I don't even use them on the street anymore unless I'm in gravel (which is rarely).

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If I understood correctly, Keith says (TOTW1) that for a sportbike, front brake only will produce the shortest stopping distance. True/ False?

 

Since you're asking about the shortest STOPPING distance I would say you need a combo of both front and back brakes. Initial rear brake to lower the rear and bring down the CG then the rest of the braking will all be on the front. Sportbikes have 2 brake calipers on the front for good reason. On the track you only need the front to scrub off some speed.

I never read TOTW1. Plan to though.

Is the effect of engine braking from the rolloff enough to "settle the rear"? FWIW, I rarely use the rear brake, mostly for holding at a light or the rare off-track excursion. It's perfectly fine with me if I never need a new set of rear pads as I'm pretty anal about those front brakes (hey, what can I say, I like to stop).

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That msf-usa.org report was very interesting. Thanks for that, Thor.

 

However, keep in mind that that report was based on "emergency braking". That is stopping the bike in the shortest distance possible with a full stop being the ultimate goal. Ultimately, like the report says, trying to modulate two independent braking systems is a very complex endeavour in any circumstance, even for an expert rider who is capable of standing the bike on its front wheel with the front brake. Add to that needing to blip the throttle for multiple downshifts in preparation for a quick turn maneuver and the level of complexity will overdraw the novice $10 bank account of attention pretty quick!

 

IMO, in an educational situation, the question becomes, what is the best or most effective way to teach and/or learn to use the brakes? I have to agree with Keith Code's philosophy that proficiency with the front brake is paramount or foundational and best precedes any advanced skills training, ie. learning to use both brakes together to gain the last tenth of one percent of stopping distance which is not really critical in a normal riding situation and is far outweighed, IMO, by the ability to focus on more important things, like smooth simultaneous downshits.

 

Personally, under normal circumstances, I find that closing the throttle to weight the front wheel is more than sufficient. I then utilize progressive braking force at the front lever and regularly lift the rear wheel under racing conditions. The only time I use the rear brake as suggested in the msf-usa report (outside of slippery conditions, ie. rain, oil or off-track grass, dirt, gravel, etc) is if the front wheel is still light after rolling off the throttle, ie. say when needing to brake while cresting a hill. And although the flywheel effect of the motor may ultimately increase stopping distance by .01 percent during an emergency stop, I NEVER pull in the clutch when braking under normal circumstances.

 

racer

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That msf-usa.org report was very interesting. Thanks for that, Thor.

 

However, keep in mind that that report was based on "emergency braking". That is stopping the bike in the shortest distance possible with a full stop being the ultimate goal. Ultimately, like the report says, trying to modulate two independent braking systems is a very complex endeavour in any circumstance, even for an expert rider who is capable of standing the bike on its front wheel with the front brake. Add to that needing to blip the throttle for multiple downshifts in preparation for a quick turn maneuver and the level of complexity will overdraw the novice $10 bank account of attention pretty quick!

 

IMO, in an educational situation, the question becomes, what is the best or most effective way to teach and/or learn to use the brakes? I have to agree with Keith Code's philosophy that proficiency with the front brake is paramount or foundational and best precedes any advanced skills training, ie. learning to use both brakes together to gain the last tenth of one percent of stopping distance which is not really critical in a normal riding situation and is far outweighed, IMO, by the ability to focus on more important things, like smooth simultaneous downshits.

 

Personally, under normal circumstances, I find that closing the throttle to weight the front wheel is more than sufficient. I then utilize progressive braking force at the front lever and regularly lift the rear wheel under racing conditions. The only time I use the rear brake as suggested in the msf-usa report (outside of slippery conditions, ie. rain, oil or off-track grass, dirt, gravel, etc) is if the front wheel is still light after rolling off the throttle, ie. say when needing to brake while cresting a hill. And although the flywheel effect of the motor may ultimately increase stopping distance by .01 percent during an emergency stop, I NEVER pull in the clutch when braking under normal circumstances.

 

racer

For the track, it would be a good idea to look at the second link. The rear brake increases stability of the bike. If you don't have the brain power to use both brakes, fine. I don't when I'm going fast, most of the time.

 

After 30 years of riding, and 7 on sportbikes, it's taken me 2 years to get a feel for the rear brake on my sportbike. It definitely decreases the "drama" of the bike when rapidly slowing. Do I use it all the time? No. It depends on how important it is to have the bike controlled. If I don't mind the bike getting a little loose and squirrely, I don't worry about it and use the clutch and down shifts to control the rear.

 

If I need the bike to be as smooth and controlled as possible, I use the rear.

 

Now how I do that is a whole different discussion.

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For the track, it would be a good idea to look at the second link.

Thanks, I will. I didn't have time yesterday.

 

The rear brake increases stability of the bike.

I didn't know that.

 

If you don't have the brain power to use both brakes, fine. I don't when I'm going fast, most of the time.

I'm thinking about the novice/student rider learning the front brake and becoming proficient with the throttle blip/front brake technique first. It seems the most logical progression before adding the rear brake to me. I myself just never bothered to learn more than that. I didn't realize there might be an advantage.

 

After 30 years of riding, and 7 on sportbikes, it's taken me 2 years to get a feel for the rear brake on my sportbike. It definitely decreases the "drama" of the bike when rapidly slowing. Do I use it all the time? No. It depends on how important it is to have the bike controlled. If I don't mind the bike getting a little loose and squirrely, I don't worry about it and use the clutch and down shifts to control the rear.

 

If I need the bike to be as smooth and controlled as possible, I use the rear.

Thanks for that info. I'll definitely check it out.

 

Now how I do that is a whole different discussion.

I'm all ears.

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The rear brake is only good for backing it in on track, Nicky Hayden has this mastered and its why he has a huge rear brake disk on his Moto Gp bike compared to Dani Pedrosa! You use the rear brake hard enough not to lock the rear but make the rear wheel rotate slower than the front, stepping the rear of the bike out and pointing the bike more into the turn, it looks mega cool when done properly but probably eats into your $10 of attention right when you need it most!

 

 

http://uk.youtube.com/watch?v=l8dMRtxjoN0

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If I understood correctly, Keith says (TOTW1) that for a sportbike, front brake only will produce the shortest stopping distance. True/ False?

 

Since you're asking about the shortest STOPPING distance I would say you need a combo of both front and back brakes. Initial rear brake to lower the rear and bring down the CG then the rest of the braking will all be on the front. Sportbikes have 2 brake calipers on the front for good reason. On the track you only need the front to scrub off some speed.

I never read TOTW1. Plan to though.

Is the effect of engine braking from the rolloff enough to "settle the rear"?

Good question. I'm BAD at blipping the throttle, and do use the engine to brake, especially at the end of the straight. In the last class I rode (I just moved up, and am middle of the pack in this again) I was easily one of the best at late braking and never use the rear brake, but I engine brake like a madman, and only have small problems with the rear coming up, but never a loss of stability.

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Ya know, now that I think about it, I don't like the term "engine braking". I think it gives a false impression. True, the engine will help to slow the speed of the rear tire against the pavement, but it's not a brake.

 

The purpose of the downshift is to setup for the drive, mid corner and at exit. The braking effect is just what you get from rolling off prior to braking and can help settle the front if the timing is right.

 

But I guess this is all off topic. I've only barely tried the rear brake technique and don't see how it contributes to rear squat (I'm sure there's a LOOOOONG thread here about that debate). Good Nite.

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Right, the engine is there to make the bike go faster, not slower.

 

Hubbard,

 

What exactly are you doing?

 

The proper form is to get the majority of the braking done first before downshifting. That makes the downshiting easier and reduces engine braking.

 

 

Thor,

 

Settling the rear. What does that mean?

 

ARe you saying that using the rear brake makes the rear of the bike squat?

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Right, the engine is there to make the bike go faster, not slower.

 

Hubbard,

 

What exactly are you doing?

There are some corners that I just have to learn, and am trying, to blip the throttle. I can't afford that loss of speed. On a big straight with a slow corner at the end, I have points, just like cornering that I hold in the clutch, start braking, downshift (on the East straight from 4th to 2nd) and engine brake (doesn't matter if anyone likes the term or not, that's what I'm doing) while I'm using the front brakes for most of my stopping. I have a point just before the turn or a little into it that I have the clutch all the way released and am back on the gas.

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Right, the engine is there to make the bike go faster, not slower.

 

Hubbard,

 

What exactly are you doing?

There are some corners that I just have to learn, and am trying, to blip the throttle. I can't afford that loss of speed. On a big straight with a slow corner at the end, I have points, just like cornering that I hold in the clutch, start braking, downshift (on the East straight from 4th to 2nd) and engine brake (doesn't matter if anyone likes the term or not, that's what I'm doing) while I'm using the front brakes for most of my stopping. I have a point just before the turn or a little into it that I have the clutch all the way released and am back on the gas.

Ah....

There are 2 techniques to downshifting. Sounds like you're using the "B" technique. IIRC Jason Pridmore and a relative few others use the technique. It costs more to use such a technique. I recommend learning and practicing the "A" technique. Take a look at this article:

http://www.sportrider.com/ride/rss/146_040...ttle/index.html

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Right, the engine is there to make the bike go faster, not slower.

 

Hubbard,

 

What exactly are you doing?

There are some corners that I just have to learn, and am trying, to blip the throttle. I can't afford that loss of speed. On a big straight with a slow corner at the end, I have points, just like cornering that I hold in the clutch, start braking, downshift (on the East straight from 4th to 2nd) and engine brake (doesn't matter if anyone likes the term or not, that's what I'm doing) while I'm using the front brakes for most of my stopping. I have a point just before the turn or a little into it that I have the clutch all the way released and am back on the gas.

 

Forgive me, I'm still not completely clear about what you are doing.

 

Engine braking happens when the clutch lever is out, ie. disengaged.

 

If you have the clutch lever pulled in, there is very little* or no engine braking.

 

If you have the clutch lever pulled in one time for multiple downshifts, there is a chance of catching a false neutral. Or if you hold the clutch in so long that the engine speed falls, the hydraulic connection of the oil in the wet clutch will create drag on the input shaft and we hear a loud clunk when shifting. This is can damage the the transmission, and again, there is a good chance you will bounce out of gear or into a false neutral.

 

I have to step out for a bit. I'll finish this later.

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Engine braking happens when the clutch lever is out, ie. disengaged.

 

If you have the clutch lever pulled in, there is very little* or no engine braking.

 

Lever pulled in is clutch disengaged= not transferring power

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Engine braking happens when the clutch lever is out, ie. disengaged.

 

If you have the clutch lever pulled in, there is very little* or no engine braking.

 

Lever pulled in is clutch disengaged= not transferring power

 

Hi Jay,

 

Yes, you are correct. However, some people consider "engage" to mean the act of pulling the lever (or pushing the pedal) itself. In any case, people use the term both ways which is why I specified which one I meant so there would be no misunderstanding.

 

 

Thanks,

racer

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Hi Hub,

 

OK...

 

You said you are having some difficulty with the throttle blipping. I don't know if you mean specifically blipping the throttle at the same time you are using the brake or just the basic skill of blipping while downshifting in the first place. But, I can offer some helpful hints that I hope will be, well, helpful.

 

If your difficulty stems from the act of trying to brake and blip at the same time, maintaining even brake pressure while blipping, the basic trick is to use only two fingers on the brake lever and to let them slide back and forth over the lever as you blip the throttle with your last two fingers and thumb on the throttle. This definitely takes some practice, so, don't give up. And wearing gloves definitely helps.

 

If you are having difficulty with blipping to match revs in the first place, then I suggest practicing downshifts without the brake to really get the hang of it first, before learning to add the brake later. Once you understand the how and why of the process, knowing when and how much to blip requires a certain degree of "touch" or "feel". Practice makes perfect. Don't give up. IMO, this is the most important foundational skill for a rider to master.

 

So, using the long straightaway as an example, the best or proper procedure to follow when decelerating in preparation for the corner is to roll off the throttle and apply the brake, leaving the bike in gear and the clutch 'engaged'. Toward the end of your braking is the time to execute any downshifts that may be required. For a number of reasons, you do not want to downshift early to use the engine as a brake. Selecting the proper gear for your road speed is the last thing you want to do before turning in and accelerating again.

 

If you have any questions, please ask. I'm glad to clarify anything I've said or try to help with anything I haven't covered.

 

racer

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What you described in your last paragraph is what I do. When I get into my braking point, that's when I let the clutch in and start braking while I downshift then let the clutch out slowly. Trust me, it's braking the bike. If you get on the highway and get up to 115 mph in 4th, downshift to 2nd and let the clutch out while you're braking until you're doing 65 mph, which is about my entry speed into the corner, that's what I do.

I work on blipping often on my way to work, and it's a booger. A friend of mine does it in a couple places on the East track, which would lower my laptimes if I could do it in those spots, but I'm just not getting it.

What I'm doing is squeezing clutch lever, cranking the throttle real quick just about the time I'm downshifting with my foot, and let the clutch back out. It isn't working for me, and unless I'm doing something wrong I just need to keep working on it until I can do it without even thinking about it. I'm an engine braking fiend.

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What you described in your last paragraph is what I do. When I get into my braking point, that's when I let the clutch in and start braking while I downshift then let the clutch out slowly. Trust me, it's braking the bike. If you get on the highway and get up to 115 mph in 4th, downshift to 2nd and let the clutch out while you're braking until you're doing 65 mph, which is about my entry speed into the corner, that's what I do.

 

I'm sorry. I'm not sure you are following me here. What you are describing is very different from what I'm suggesting in my last paragraph.

 

 

I work on blipping often on my way to work, and it's a booger. A friend of mine does it in a couple places on the East track, which would lower my laptimes if I could do it in those spots, but I'm just not getting it.

What I'm doing is squeezing clutch lever, cranking the throttle real quick just about the time I'm downshifting with my foot, and let the clutch back out. It isn't working for me, and unless I'm doing something wrong I just need to keep working on it until I can do it without even thinking about it. I'm an engine braking fiend.

 

The throttle blip is a quick short very small "blip". And is done nearly simultaneously with letting the clutch lever back out. The entire process takes about a quarter of a second.

 

First, do not pull in the clutch lever at all until you are ready to downshift. The throttle is closed while you are decelerating.

 

Then... when you are ready to accelerate again, quickly pull in the clutch just enough to reach the disengagement point (not all the way to the handlebar), give the throttle a short little blip and shift the gear pedal down one gear only, and quickly release the clutch in that order. But, very quickly so the motor rev's do not have time to fall again. When you pull in the clutch, you are almost already blipping and shifting and then letting the clutch pop back out in one quick action. The blip and shift is a nearly single simultaneous motion. When done right, the whole thing takes about 2 tenths of a second. And remember, shift ONLY ONE GEAR at a time. If you need to go down another gear, repeat the entire process for each shift.

 

racer

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OK, with engine braking, if you didn't get it, I don't know how else to explain it. It's something you'd have to do, but you did explain it properly.

 

And with the blipping, what I do is backwards I think.

What I'm taking is that I need to shift THEN blip and release the clutch lever. If that's what I'm supposed to be doing, it would explain my problem.

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And with the blipping, what I do is backwards I think.

What I'm taking is that I need to shift THEN blip and release the clutch lever. If that's what I'm supposed to be doing, it would explain my problem.

 

No. You don't have it. Read it again.

 

The whole point of blipping the throttle is to raise the engine rev's to match what is needed in the next gear. It is the opposite of the rev's falling when you shift up. Get it? Hence, the order is self-explanatory.

 

Clutch in. Blip. Shift. Clutch out.

 

There is practically no time between these actions. They are done almost on top of each other in one fluid motion. As a learning tool, for the goal of getting the feel of it, you can apply a slight pressure to the gear shift pedal prior to pulling in the clutch and blipping, then, the bike will basically shift itself when the 'blip' hits the right rev point. Try that to get the idea of the timing and revs you need. Once you have it, don't pre-load the shifter anymore. If you do it too hard, you can cause damage.

 

Good luck. Out.

 

r

 

PS - Forget about the engine braking thing. I get it. It's just what happens when you roll off the gas on a four stroke. It isn't really relevant to what you need to learn here.

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OK, with engine braking, if you didn't get it, I don't know how else to explain it. It's something you'd have to do, but you did explain it properly.

 

And with the blipping, what I do is backwards I think.

What I'm taking is that I need to shift THEN blip and release the clutch lever. If that's what I'm supposed to be doing, it would explain my problem.

Thou hard way is sure to land thee on thine ass. If thee didn't get the Sportrider article, here is the article from thy beloved KC: http://forums.superbikeschool.com/index.php?showtopic=258

Go forth and do great things.

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