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Jaybird180

Turning And Braking

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I'm rereading Keith's article on Bad Lefts or Rights http://forums.superbikeschool.com/index.php?showtopic=111 as I'm thinking about something I experienced at my last track outing. I had some trouble making right turns. On at least two laps in T4, I was on the brakes hard and had to say to myself "Get it turned NOW" as the bike didn't seem to want to steer. I'm questioning if it was (1) rider error (pressing on both bars with equal pressure), (2) geometry issue (excess trail), or (3) normal extra steering effort required because of braking forces. (4) I also have very little experience with the HESD (Honda Electronic Steering Damper), which increases damping based on speed - at least according to the marketing write-ups I've read). I'm leaning more toward #1 & 3 with more emphasis on #1.

 

Is #3 normal? Am I just being a wuss? Keith discusses #1 in the article and I'm clearly open to that possibility. I'm also VERY open to doing the steering drill discussed until turning issues have vanished. Is #4 even a factor?

 

But for now I'm looking to assuage my feelings on why I had this issue making right turns. FWIW- there were no hard (or trail) braking left corners at the track I was riding, at least not for my style of riding, so I can't say that I'd have similar problems going left. I would imagine not, because of the attention on the right fingers squeezing the brake lever; me, the rider, probably wouldn't have the same trouble on trailbraking left turns. Just a theory. I'd like to know if this makes sense to anyone else.

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.........

Is #3 normal?.......

 

Number 3 is not normal.

The front contact patch grows when some (or all) weight is transferred forward (increasing tire-asphalt friction), but the trail is reduced, which makes steering lighter (it requires less effort).

Trail is the distance that the front wheel ground contact point trails behind the steering axis ground contact point.

 

https://en.wikipedia.org/wiki/Bicycle_and_motorcycle_geometry#Trail

 

https://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics#/media/File:Bicycle_dimensions.svg

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Assuming the truth of what you say it leaves as most likely #1 - unwanted rider pressure on the bars.

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Assuming the truth of what you say it leaves as most likely #1 - unwanted rider pressure on the bars.

 

That is by far the most common cause. How are you dealing with the braking forces? What parts of your body do you use to keep yourself from sliding/tipping forward under hard braking?

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Assuming the truth of what you say it leaves as most likely #1 - unwanted rider pressure on the bars.

 

That is by far the most common cause. How are you dealing with the braking forces? What parts of your body do you use to keep yourself from sliding/tipping forward under hard braking?

 

 

Well, I can tell you for certain that I don't habitually have a strong lower body lock under braking as I'm normally off the brakes by the time I'm ready to turn-in. Bar pressure hasn't been a concern and actually I've wanted to use bar pressure so I can "set" and feel the front end dive (stock suspension on this bike).

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Assuming the truth of what you say it leaves as most likely #1 - unwanted rider pressure on the bars.

 

That is by far the most common cause. How are you dealing with the braking forces? What parts of your body do you use to keep yourself from sliding/tipping forward under hard braking?

 

 

Well, I can tell you for certain that I don't habitually have a strong lower body lock under braking as I'm normally off the brakes by the time I'm ready to turn-in. Bar pressure hasn't been a concern and actually I've wanted to use bar pressure so I can "set" and feel the front end dive (stock suspension on this bike).

 

 

What do you think would happen to the front end under hard braking if you did NOT put any arm pressure on the bars? Would the braking forces still compress the forks?

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Because I brake like a weenie- not much compression of the forks. LoL

 

I dunno. I've not thought much about it or tried it. Perhaps my compression damping is set too stiff to know.

Hmmmmm.....maybe I've been using the stiff compression damping as a crutch for bad technique!

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One factor...not sure it was addressed above: when braking and turning, the bike actually tries to countersteer up, out of the turn, and that force does have to be resisted.

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What does this mean, "countersteer up, out of the turn"?

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Steering into the turn, does it make sense that you steer into the turn by countersteering---push right to lean the bike to the right, stop pushing at the desired lean angle?

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So you're saying that when braking, the bike will resist the rider's efforts to turn. Got it.

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After the initial action of countersteering, which only is done till the bike is leaned to the point needed to get onto line, then the front comes back around (pro-steering) and continues on through the turn. If while the bike is in the pro-steering part the front brake is applied, then it countersteers the bike some more, and one would have to resist that pressure on the bars to keep the bike from lifting up.

 

Make sense?

 

CF

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I don't think I've experienced that sensation - at least not in recent memory - gotta get out and ride more (and make more errors ???).

 

In my OP, I was referring to the difficulty in getting the initial steering done.

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Yeah, when you get some weather that allows some riding, do a little experimenting with the steering.

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The front contact patch grows when some (or all) weight is transferred forward (increasing tire-asphalt friction), but the trail is reduced, which makes steering lighter (it requires less effort).

 

 

 

So you're saying that when braking, the bike will resist the rider's efforts to turn. Got it.

 

So... is it EASIER or HARDER to turn the bike on INITIAL turn-in, when braking hard?

 

More difficult to turn due to extra weight on the front tire makes sense, but, so does EASIER to turn due to change in geometry... I realized I don't know which is the greater effect Does the additional weight on the front under heaving braking create MORE extra effort than is offset by the change in geometry caused by the fork compression, or less? (I'm sure this will depend somewhat on suspension settings and maybe also tire profile and pressure, but let's assume a well set-up sport bike with sport/track tires, something like Q3s.)

 

In thinking about it, I realized I don't know from experience... because due to available traction on the front tire, I never TRY to turn the bike as quickly under heavy braking as I do if I am braking lightly or releasing the brake as I turn it. Since we are sharing available front tire traction between braking forces and turning forces, I would reduce my steering rate and lean angle under heavy braking, so there is no circumstance that I can think of where I would attempt to steer at exactly the same rate and at the entry same speed with and without hard braking to test whether the required steering effort changed.* It seems, in fact, like a difficult experiment to carry out, since accurately gauging the difference in your steering pressure while simultaneously attempting to brake hard and turn the bike quickly, PLUS hit the turn point at the exact same entry speed as you did with no or light brakes, seems like it would be quite difficult!

 

My personal sense of it is that the geometry change has a greater effect, so steering would be lighter under heavy braking, but my recent riding experience where I actually USE heavy braking is in racing where I am using a bike with a relatively soft front suspension and racing tires that are pretty stiff. I think a mushy front tire would make a BIG difference in how the turn-in would feel under hard braking.

 

(*Actually there is one circumstance I can think of, which is using the front brake in the middle of a chicane to get it to transition from side to side more quickly; that really would not fit my definition of HARD braking, but it would be making use of the effects of braking on steering - both the mid-corner effect of sudden braking causing the bike to want to stand up AND the compression of the forks helping it to rapidly steer the other direction.)

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The front contact patch grows when some (or all) weight is transferred forward (increasing tire-asphalt friction), but the trail is reduced, which makes steering lighter (it requires less effort).

 

 

 

So you're saying that when braking, the bike will resist the rider's efforts to turn. Got it.

 

So... is it EASIER or HARDER to turn the bike on INITIAL turn-in, when braking hard?

 

More difficult to turn due to extra weight on the front tire makes sense, but, so does EASIER to turn due to change in geometry... I realized I don't know which is the greater effect Does the additional weight on the front under heaving braking create MORE extra effort than is offset by the change in geometry caused by the fork compression, or less? (I'm sure this will depend somewhat on suspension settings and maybe also tire profile and pressure, but let's assume a well set-up sport bike with sport/track tires, something like Q3s.)

 

In thinking about it, I realized I don't know from experience... because due to available traction on the front tire, I never TRY to turn the bike as quickly under heavy braking as I do if I am braking lightly or releasing the brake as I turn it. Since we are sharing available front tire traction between braking forces and turning forces, I would reduce my steering rate and lean angle under heavy braking, so there is no circumstance that I can think of where I would attempt to steer at exactly the same rate and at the entry same speed with and without hard braking to test whether the required steering effort changed.* It seems, in fact, like a difficult experiment to carry out, since accurately gauging the difference in your steering pressure while simultaneously attempting to brake hard and turn the bike quickly, PLUS hit the turn point at the exact same entry speed as you did with no or light brakes, seems like it would be quite difficult!

 

My personal sense of it is that the geometry change has a greater effect, so steering would be lighter under heavy braking, but my recent riding experience where I actually USE heavy braking is in racing where I am using a bike with a relatively soft front suspension and racing tires that are pretty stiff. I think a mushy front tire would make a BIG difference in how the turn-in would feel under hard braking.

 

(*Actually there is one circumstance I can think of, which is using the front brake in the middle of a chicane to get it to transition from side to side more quickly; that really would not fit my definition of HARD braking, but it would be making use of the effects of braking on steering - both the mid-corner effect of sudden braking causing the bike to want to stand up AND the compression of the forks helping it to rapidly steer the other direction.)

 

 

Very lucid and well structured response. I seem to recall (quite fondly) a guy here who's now banned who described this as an intentional highside maneuver. I remember thinking that anyone that does that is Sierra Hotel.

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This would be one of those things it would be not so easy to measure (force needed during turning, while braking). Really have to work to get the same force on tires, then see how much braking, how much change in the bike's geometry (fork compression), etc., etc.

 

My gut feel is that it is harder to steer when the brakes are on, whether at turn in or later in the turn "trailing the brakes". As Hotfoot mentions, this is a little hard to test, as if you blow it...it could get expensive.

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This would be one of those things it would be not so easy to measure (force needed during turning, while braking). Really have to work to get the same force on tires, then see how much braking, how much change in the bike's geometry (fork compression), etc., etc.

 

My gut feel is that it is harder to steer when the brakes are on, whether at turn in or later in the turn "trailing the brakes". As Hotfoot mentions, this is a little hard to test, as if you blow it...it could get expensive.

Many riders report easier turn-in and it has been attributed to geometry. Some bikes are setup statically so steep that turning on the brakes makes them ultra-quick but unstable; I've never experienced that.

 

YCCS teaches trailing early in their curriculum. Their rationale for so doing is incompatible with CSSs principles (IMO). I'd have to work at it, but I had conversation with someone who's earned a club racing championship (2014 IIRC) and has trained with both. Maybe I could get in touch with him and see if he's willing to chime into the discussion?

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YCRS does talk about trailing the brakes, and often we get compared that we don't. Not quite accurate, we actually have skills for this. Some turns one must trail the brakes way into the turn like a long, late apex decreasing radius turn. Other turns trailing the brakes late into the turn makes it not possible to turn the bike quickly, and delays throttle roll on unnecessarily.

 

Look at where most of the crashes happen at MotoGP...at turn entry, carrying the braking too much, too far.

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Thanks for brining that up Cobie. I'd like to elaborate. I had a private discussion with someone (2 somones actually) on this forum about the differences in teaching style. One person was so kind as to caution me against hinting that I was a CSS student. I took his advice but alas something gave it away at the trackday.

 

At any rate, there exists the errant misinformation (and YCRS instructors might be responsible for some of it) that CSS is against trail braking. I found through my own experiences this to be false, misleading and potentially defamatory. Not only that, spreading such rumor can be disruptive to safe, controlled riding techniques by persons of less than advanced skill.

 

(are we Off-Topic? - what the heck!) MotoGP crashes happen less mid-late turn because of electronics. There's a video around of Wayne Rainey saying that he thinks there is too much electronics in MotoGP racing. I think the trend of streetbikes having so many "rider aids" just might spawn a new generation of riders who will not learn the skill of good throttle control and sense of rear tire traction.

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Electronics...yeah, might be a new thread. I'll mention one thing: when we switched from the 600's to the (at the time) most powerful street bike released, crashes went down over 35% at the School. We could take a look at why...see what comes up. Some people thought we were crazy.

 

Should we start a new thread on this, let me know what you guys think.

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Electronics...yeah, might be a new thread. I'll mention one thing: when we switched from the 600's to the (at the time) most powerful street bike released, crashes went down over 35% at the School. We could take a look at why...see what comes up. Some people thought we were crazy.

 

Should we start a new thread on this, let me know what you guys think.

 

I think we have more than one already in existence on electronics - here are a couple I found with a quick search, and I saw another on ABS...

http://forums.superbikeschool.com/index.php?showtopic=3952&hl=electronics

and this one

http://forums.superbikeschool.com/index.php?showtopic=4536&hl=electronics#entry39864

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