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Old 11-09-2012, 04:42 PM   #256
ibafran
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Quote:
Originally Posted by outlaws justice View Post
I will repeat this for the benefit of those that did not bother to actually read it the first time.

"If you are using the brakes you are braking. When you should be or not be braking it is still braking. If one person brakes further into a corner than the next person he is just braking deeper into the corner.

And since you also want to quote books here again is one from a book diagraming trail braking in a curve.



If you want the true defeninition maybe talk to those who actually created the technique and those who are the ones who write the books. Have you spent any time talking to people like Freddy Spencer or Lee Parks in person, maybe instead of sitting here telling everyone how great you are take some time to sit down, ride with and get some pointers from those guys. What you think you know and what you know might turn out to be two different things"

No Offence, but I will listen and believe what these guys take the time to explain and show me in person and work with me to improve. And I know for a fact when you pick up the phone and call some of these guys they are more than willing to talk to you and help you understand. And when working with them in person they take the time to make sure you get it right and understand all the components involved.
ALL: Thanx for that diagram as I had yet to see that. I note that most of the curves are pretty gentle except for the blue lean angle line 'snap-over' to intitate the max lean plus the long part where nearly 100% of lateral traction is graphed along the top. That leads me to believe that the tires will be quickly loaded for max lean without the brakes (or throttle for that matter) being unloaded nearly as quickly. Where the red and the blue line cross looks like it adds up to more than 100%/points of available traction? So the tire must lose traction there according to the graph. I await clarification by anyone? It seems to me that the red 'trail braking' line does not drop off well enough to keep the sums at or less than 100%/points? Good luck doing the verticle axis sums for the lean angle/throttle as well?
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Old 11-09-2012, 05:01 PM   #257
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Originally Posted by ibafran View Post
ALL: Thanx for that diagram as I had yet to see that. I note that most of the curves are pretty gentle except for the blue lean angle line 'snap-over' to intitate the max lean plus the long part where nearly 100% of lateral traction is graphed along the top. That leads me to believe that the tires will be quickly loaded for max lean without the brakes (or throttle for that matter) being unloaded nearly as quickly. Where the red and the blue line cross looks like it adds up to more than 100%/points of available traction? So the tire must lose traction there according to the graph. I await clarification by anyone? It seems to me that the red 'trail braking' line does not drop off well enough to keep the sums at or less than 100%/points? Good luck doing the verticle axis sums for the lean angle/throttle as well?
Believe that is % of brake, throttle, and lean. Traction is not addressed in that graph, I don't believe.

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Old 11-09-2012, 09:39 PM   #258
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Also in reality the transition onto the brakes and off the throttle happens much quicker than that.

The biggest break through for me in my riding / driving career was what smooth actually means. The old adage "slow is smooth, smooth is fast" is true.

But we have to discuss what "smooth" is actually meant to be. The way I personally define it is bringing the tire to maximum traction as quickly as possible with out exceeding it and keeping it there.

So if you where looking a circular plot of acceleration. You'd see it shoot from being slight acceleration to hard deceleration Then as the cornering load comes on (lateral acceleration) you wouldn't see the G ball move back into the middle it would trace an arch at the same total acceleration directly over to full lateral acceleration and then it would trace a line back to the center as acceleration started taking over, but it would never actually return to the center or dip below peak g-forces....


That's the goal anyhow. How well you can do that, every turn, with whatever setup is on your bike, in any condition is what separates the good from the great and the great from legends.



Watch a master class in riding from about 4 min on.

crofrog screwed with this post 11-09-2012 at 10:01 PM
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Old 11-10-2012, 03:00 AM   #259
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Originally Posted by crofrog View Post
Watch a master class in riding from about 4 min on.

Mr. Frog, I watched the entire video. It was very good. That Mr. Jorge is very exiting, though he could be a lot faster. If you watch the graph at the bottom of the screen, it would be lit up green for acceleration, then transition very quickly to red for braking with no overlap. If he wants to be really fast he has to overlap the two and combine throttle and braking.

Do we know anyone that could straighten him out?



























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Old 11-10-2012, 07:05 AM   #260
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.....I'll leave it. That was great.
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Old 11-10-2012, 07:43 AM   #261
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Originally Posted by Barry View Post
Believe that is % of brake, throttle, and lean. Traction is not addressed in that graph, I don't believe.

Barry
ALL: Lots of info surrounding that graph was not included with the post. Considering the way the graph looks, I am willing to guess that it is for a fairly tight corner, something akin to a hairpin with a constant radius. The graph shows time into corner equal to time exiting corner. Certainly, a long sweeper would not have the nearly(?) shut throttle. The blue graph line shows a 'nearly' 100% lean angle. I have no idea how to understand that graphed blue line to mean anything less than peg down, max slip angle before slide, traction? According to Bernt Spiegel, "Upper Half..." there is about 10% traction left at max lean angle for braking or throttle. Thus, a similar graph for a sweeper would show a lot of lean angle with the throttle not bottomed on the graph. If the graph is meant to be a generalized pict-o-gram of relationships and not accurately reflect properties of traction and time, readers should know that up front.

Occasionally, video race coverage shows a pair of bar graphs with live telemetry, green for throttle and red for brakes. It is hard for me to see any overlap in that coverage? And using the pause control to get some stop action on those graphs, it looks like the racers are done with braking before tip-in. Perhaps the telemetry as seen on TV isn't good enough to show a miniscule trailing brake pressure?

Some years back, Cycle World loaded up a race bike with electronic data acquisition and ran it at a track using the racer, a gifted amature, and a pretty good street rider. The idea was to see where the differences were between the levels of skill. The racer was concerned that the magazine article would 'give away' all his hard won knowledge. After some reflection, the racer decided that it wouldn't make any problems for him. Anybody reading the print would still have to ride the ride, consistantly, lap after lap in order to beat him. And that required actual practice to attain the skill. The racer figured that it mattered not what another rider might know out of a book. What mattered to the racer is what another rider can really do.

At one time, a noob in an MSF-BRC had to learn and demonstrate being able to stop in a curve. They didn't call it 'trail-braking'. But the princples of execution are the same. The racers and the cone-killers don't usually have to execute the full stop. But us street riders might very well have to. Which is why us old street riders slow down whenever our line of sight gets shortened. Do we (all us bikers) have the habit of dragging some brake into our corners? Does that work for us and enhance our safety over the long term as believed by to original thread quote? How do we keep tabs on riders who habitually trail brake and riders who don't for the long term and learn who lives longer? Let's just say we could execute that study and get an answer. What kind of study would we need to measure the happiness quotient between the two groups due to the ability to trail brake?

The MSF at one time believed stopping in a turn to be a useful and essential skill. The basic supposition of this thread is that trail braking is an essential skill and needs to be understood so that anyone can develope it and use it everywhere. Several posts say that street riders who habitually trail brake are riding poorly and accepting too much risk for the long term. It is difficult to argue against that. Having a finger on the brake with the brake light lit and the pads at the disc surface and the front suspension free of braking loads to absorb pavement irregularities entering a corner is not what I would define as trail braking. Maybe that is all that Nick is looking for in a street rider?
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Old 11-10-2012, 08:54 AM   #262
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One of the problems with trail braking that does not seemed to have been touched on so far is the effect of the riders weight being thrown onto the bars as the bike slows down before and during the corner.

As the bike leans, so the geometry ensures that the front wheel adopts it's optimum position (steering angle) to balance out all the forces. The bike is designed to do this without any rider input (apart from the initial steering input) as you will remember from when you rode your push-bike around no-handed. Any additional input during this process is bound to have an effect of some kind.

The design of the bike is pretty poor when it comes to supporting the riders weight during braking which means that the rider has to be able to support themselves in some way with the amount of support required varying proportionally with the amount of braking effort.

For most of us, we find that support by pushing back against the handlebars rather than using our trunk muscles and a firm grasp of the tank with our knees. As can be imagined at 1G deceleration the force on the bars is quite high which can prevent the steering from working as well as it wants to by adding a significant damping effect.

Would be interesting to know whether any experiments have been done to see how large (or small) any effects are.
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Old 11-10-2012, 09:17 AM   #263
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Quote:
Originally Posted by Motogymkhanaman View Post
One of the problems with trail braking that does not seemed to have been touched on so far is the effect of the riders weight being thrown onto the bars as the bike slows down before and during the corner.

As the bike leans, so the geometry ensures that the front wheel adopts it's optimum position (steering angle) to balance out all the forces. The bike is designed to do this without any rider input (apart from the initial steering input) as you will remember from when you rode your push-bike around no-handed. Any additional input during this process is bound to have an effect of some kind.

The design of the bike is pretty poor when it comes to supporting the riders weight during braking which means that the rider has to be able to support themselves in some way with the amount of support required varying proportionally with the amount of braking effort.

For most of us, we find that support by pushing back against the handlebars rather than using our trunk muscles and a firm grasp of the tank with our knees. As can be imagined at 1G deceleration the force on the bars is quite high which can prevent the steering from working as well as it wants to by adding a significant damping effect.

Would be interesting to know whether any experiments have been done to see how large (or small) any effects are.

I'm certain they have. If you notice most bikes with a sport application in mindfrom 600cc and up to WSBK dream rigs have similar geometry, you can expect 45-60mm of trail with ~24* rake 55" wheelbase and the longest swing arm you can jam behind the cases.

They didn't get there by chance, that is decades of trial and error and mucho money to arrive at those numbers.

...another thing to remember is that when you are really on the binders, the trail decreases significantly due to fork compression which makes the bike tip in faster. I'll use this at the track in fast left/right transitions to load the front end and get the bike to snap over faster.
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Old 11-10-2012, 12:45 PM   #264
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@ ibafran

First, for the scope of this message, what I mean by "trail braking" is: "slowly releasing the brakes until we can see the exit".
Also. pushing to the limits is always risky on the streets, so we are absolutely not talking about race like riding on the streets.

Quote:
Do we (all us bikers) have the habit of dragging some brake into our corners? Does that work for us and enhance our safety over the long term as believed by to original thread quote? How do we keep tabs on riders who habitually trail brake and riders who don't for the long term and learn who lives longer? Let's just say we could execute that study and get an answer. What kind of study would we need to measure the happiness quotient between the two groups due to the ability to trail brake?
I think that trail braking enhances our safety over the long term. I explained why I think so in several previous messages (trying not to repeat myself and be boring). My opinion is based on my personal experiences and observations, so we may disagree.

What do you mean by "happiness quotient"? For example, some people feel very happy when risking their lives. Happiness in not an objective measure, so we cannot use it to determine the effectiveness of a technique. We need something we can really measure.

In view of safety on the road - it is possible to imagine an experiment, but probably impossible to conduct it except by using a video simulator (which is not a proper test because it eliminates the fear factor). The experiment would include a twisty road with poor visibility (e.g. trees near both the sides of the road) and having "events" occurring when the rider doesn't expect them, such as: oncoming vehicles, animals jumping from the side of the road, oil/sand stains in the middle of the corners, cars parked on the apex of a corner, and so on. Rider "A" should use trail braking, and rider "B" should accelerate through every corner, and rider "C" should maintain the same speed. None of them should know if the obstacles exist, let alone when and which will show up. Measure of effectiveness of each technique (in terms of road safety) would be the percent of avoided crashes, and the comparison of impact speeds in cases when obstacle is not avoided. Of course, it is not possible to safely conduct experiment like this, so we will never have the reliable results.

But, anyone can go for a ride and try to imagine situations like these in the worst possible moment while riding, and judge for himself if he will be able to avoid the crash.

My opinion is that the safest way in most cases (but not all) is to use the trail braking because it gives the rider the best "initial terms" in negotiation with the trouble in the corner, which is a primary concern in view of safety. I also explained why I think so, earlier in this thread.

Quote:
Several posts say that street riders who habitually trail brake are riding poorly and accepting too much risk for the long term. It is difficult to argue against that.
I disagree, because I find arguments in favor of the trail braking on the street more convincing and logical then the opposing arguments, and also in accordance with my personal experience. I haven't met anybody who crashed because of trail braking (though I am sure there are cases), but I know people who ran wide or got into trouble by not being able to react in time, because they accelerated through the corner and were afraid to touch the brakes. I described the situation in which a no-trail-braking friend of mine and I approached the corner with the same speed, but he ran wide just because he was taught not to touch the brakes while leaning.

So, based on my experience, I can not agree with: "that street riders who habitually trail brake are riding poorly and accepting too much risk for the long term".

Quote:
Having a finger on the brake with the brake light lit and the pads at the disc surface and the front suspension free of braking loads to absorb pavement irregularities entering a corner is not what I would define as trail braking. Maybe that is all that Nick is looking for in a street rider?
There is a very good explanation of what he means: http://www.youtube.com/watch?v=G1rlQ0NmbWs



---

As somebody said to me before: "this should not be the only way you know how to ride". It is all a matter of how comfortable someone feels using this or that technique, and there is no only one "right way". I don't like preaching about the one and only correct way to ride, no matter what it is. And I also avoid satanising any technique just because I don't feel comfortable using it, it seams more like trying to delude myself that I know best.
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Old 11-11-2012, 01:03 AM   #265
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Quote:
Originally Posted by Andrew011 View Post
In view of safety on the road - it is possible to imagine an experiment, but probably impossible to conduct it except by using a video simulator (which is not a proper test because it eliminates the fear factor). The experiment would include a twisty road with poor visibility (e.g. trees near both the sides of the road) and having "events" occurring when the rider doesn't expect them, such as: oncoming vehicles, animals jumping from the side of the road, oil/sand stains in the middle of the corners, cars parked on the apex of a corner, and so on. Rider "A" should use trail braking, and rider "B" should accelerate through every corner, and rider "C" should maintain the same speed. None of them should know if the obstacles exist, let alone when and which will show up. Measure of effectiveness of each technique (in terms of road safety) would be the percent of avoided crashes, and the comparison of impact speeds in cases when obstacle is not avoided. Of course, it is not possible to safely conduct experiment like this, so we will never have the reliable results.

But, anyone can go for a ride and try to imagine situations like these in the worst possible moment while riding, and judge for himself if he will be able to avoid the crash.
Given that all three of them aim for the same cornering speed, in my opinion the accelerating rider is safest, because up to the apex he is always slower than the other two. Thus he has more time to react, a shorter braking distance and more reserves.

Quote:
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I know people who ran wide or got into trouble by not being able to react in time, because they [...] were afraid to touch the brakes. I described the situation in which a no-trail-braking friend of mine and I approached the corner with the same speed, but he ran wide just because he was taught not to touch the brakes while leaning.
Being afraid to brake while leaning is something completely different from not to habitually trailbrake. That's not even apples and oranges what you are trying to compare. In addition, according to your description your friend aimed for a higher cornering speed, otherwise you wouldn't have had the same entry speed.
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Old 11-11-2012, 10:21 AM   #266
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Anyone watch MotoGP today? I paid real close attention to the throttle and brake telemetry. None of them was on the brake and the gas at the same time. Not one. I'd be happy to be proven wrong if someone has a screenshot of both.
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Old 11-11-2012, 11:01 AM   #267
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Anyone watch MotoGP today? I paid real close attention to the throttle and brake telemetry. None of them was on the brake and the gas at the same time. Not one. I'd be happy to be proven wrong if someone has a screenshot of both.
With out knowing how the telemetry works for the bikes it's hard to say what is actually happening...

Generally speaking brake telemetry is confusing because all you can do is look at line pressure and there's no "maximum" so you end up looking at deceleration with a G-meter.

I'm guessing they're probably using an acceleration meter for the brakes and getting the throttle off the bike just because I've seen shots where the meter says they're on the throttle and you can see the foot on the rear brake pedal.
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Old 11-11-2012, 11:02 AM   #268
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Originally Posted by Jim Moore View Post
Anyone watch MotoGP today? I paid real close attention to the throttle and brake telemetry. None of them was on the brake and the gas at the same time. Not one. I'd be happy to be proven wrong if someone has a screenshot of both.
I'm halfway through it. Need to finish it, but that is what I expected...

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Old 11-11-2012, 12:04 PM   #269
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Originally Posted by crofrog View Post
With out knowing how the telemetry works for the bikes it's hard to say what is actually happening...

Generally speaking brake telemetry is confusing because all you can do is look at line pressure and there's no "maximum" so you end up looking at deceleration with a G-meter.

I'm guessing they're probably using an acceleration meter for the brakes and getting the throttle off the bike just because I've seen shots where the meter says they're on the throttle and you can see the foot on the rear brake pedal.
Nah, the relatively primitive stuff they use in motorcycle magazine tests can show throttle position. I'm sure the telemetry is legit. I kinda wonder if the timing is perfect.

They use the rear brake pedal to keep the front wheel down as they accelerate..
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Old 11-11-2012, 01:11 PM   #270
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good article by the OP, just wanted to say thanks, however late, for posting.

As for me, I'm far from an expert, I've never raced, I'm not fast, never done a track day, don't ride off road, but I've taught a few the basics of riding and IMO one of the best, most valuble things that I pass along to my "students" is some form of the quote below.

"The best thing to do before taking a corner is to scan with your eyes, use your brakes until you’re happy with your speed and direction, sneak open your throttle to maintain your chosen speed and radius, don’t accelerate until you can see your exit and can take away lean angle."

To me, it's one of the basic tenets of biking.
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