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faffi

Throttle and brake timing question

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A tuner and coach - there is a video on utube, but I understand that is best left unlinked - gives a student advice of braking, then giving the bike maintenance throttle and only then turn at a particular corner. To me, as a trail braker, this sounds weird, but are there situations where this is the best approach?

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I know the video you are referring to. I advise that you search for other racer forums discussing this idea. There is a LENGTHY debate on another forum on what he possibly could have meant when he explained it that way. It's obviously confusing even to the top tier of current and capable racers, the discussions make that apparent, I really didn't see anything from anyone that made it make sense. 

It's SO confusing that I respectfully request you change the title of your post to something more like "throttle and brake timing question" so that we don't have students reading that title and getting confused about what the normal sequence should be. 

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IMHO, the tuner is basically advising against precautionary coasting on a turn (50/50 weight distribution), which delays maintenance acceleration until the way out of the turn is visible and verified as safe (street visual technique).  The rear suspension and tire are needlessly unloaded for too long, which is later visible in the rubber wear texture.

I see no contradiction with Keith's technique of 0.1 to 0.2 G acceleration applied as soon as possible on the turn in order to achieve 60/40 weight distribution and suspension and chassis stabilization.

That is impossible to do while deep trail braking up to the apex: there is always a percentage of over-loading on the front suspension and tire (and the opposite for the rear end) during the first section of the curve.

During trail braking, the weight distribution remains reversed and far from the ideal 40% front/60% rear, condition that improves (tends to 50/50) as you approach the apex and gradually reduce hand pressure on the front brake lever.

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I do not have any issues with turning in on maintenance throttle, but to first brake, then go to maintenance throttle and only then turn seems at best complicated to me. Especially for a beginner. Timing seems incredibly difficult, particularly for a novice or someone clumsy like me. Also, for racing, I reckon it would quickly cause havoc if a rider were to brake much sooner then anybody else.

However, that was why I asked the question in the first place; are there any track corner where this would clearly be the preferred way, so much so that every racer would brake prematurely (compared to most corners) in order to cut the lap time?

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The very first thing I learned from Keith was from that classroom scene in the TOTW II video: "Once the throttle is cracked open, it is rolled on evenly, smoothly and constantly throughout remainder of turn." In my opinion, when I feel I need maintenance throttle it is because my entry speed was too low. I can't imagine getting on the gas before turn in. In some sections like turns 4/5/6 at SOW, I may not ever close the throttle all the way but just stop rolling on while turning.

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I know the video. I know the tuner and have had my bike tuned by him. I've consulted with him on reading my tires. The video confused me too, but only when trying to make it fit into CSS philosophy. He's not the only advocate of this timing method (I did a 2-up ride with such person who runs a long-standing school at an East Coast track).

The best I can say about it, is that the goal is to untrain street habits with throttle shyness. However, it can become a potential issue if applied as a "this is how you ride' mantra as it will require the geometry to be setup with a bias to account for this style.

Thanks for starting the discussion on it. I wanted to but didn't know a good way to discuss it; I'm glad you did.

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Let's touch on one thing: bike doesn't turn as well when the throttle is on, even just maintenance throttle.  When off throttle, bike weight is forward, more on the front, steering angle is steeper, wheelbase is shorter--the bike turns better.   Does anyone know a single turn where braking is done, then gas on, then bike turned,?  

As mentioned earlier by trueblue550 (Streets of Willow Springs) there are series of turns where the throttle is stopped for a moment to complete the steering (T 4-5), or where rolling it on puts the rider too wide for the next turn in point (T5-T6).  These are situations where there is a series of turns, the following one dictating the exit of the previous turn.

 

 

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Cobie you bring up a good point. Unfortunately when the throttle is on, two things are happening that impacts turn radius: geometry and gyroscopic effect. We can account for geometry by creating a chassis setup to accommodate the style. I think it would be harder (but measurable) to account to gyroscopic forces. I don’t know if more bar pressure can overcome the penalty.

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On 9/16/2019 at 2:19 PM, faffi said:

I do not have any issues with turning in on maintenance throttle, but to first brake, then go to maintenance throttle and only then turn seems at best complicated to me. Especially for a beginner. Timing seems incredibly difficult, particularly for a novice or someone clumsy like me. Also, for racing, I reckon it would quickly cause havoc if a rider were to brake much sooner then anybody else...

Perhaps you and I are watching different videos, or have different interpretations, or the way he explained the concept was poor, but it seems to me that the tuner was not purposely advising exactly that "brake-open throttle-turn in" timing sequence.

The way I see it, that gentleman was asking the rider, whose suspension was being adjusted, not to be shy or excessively cautious about giving some gas to the engine during the first phase of a regular curve (not to coast), but rather achieving the proper weight distribution as early as possible, not over-loading the front contact patch (which needlessly over-stresses its surface), which condition when back from a spin (plus the height of the zip-tie) was the tuner's reference for finer adjusting of spring and damping.

I believe that the tuner would never be able to notice any difference (regarding texture of surfaces of the tires) between the two sequences: "brake-open throttle-turn in" or "brake-turn in-open throttle", any thing that happens there just happens too fast to make any difference.

In the video I watched, the tuner was able to see that the rider had done some wheelies during a lap because contradictory clues: the zip-tie moved too high (much weight on front suspension when landing back), but under-stress of the rubber surface (not enough cornering and braking forces/overall low speed).

Best (non-dynamic) suspension always means best possible managing of dynamic weight transfer to pavement for most conditions, regarding forces and accelerations of braking, cornering and exiting a curve.  Lacking more sophisticated sensors on the bike, the tuner's expert diagnostic fully relies on the visual clues of rubber surface (what pavement does to rubber during the periods of times the curves last) and range of suspension strokes after one or more laps, reason for which he needs the rider to keep smoothness and weight distribution as close to ideal as possible.

As always, I could be wrong, though.

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I tried it once.  Brake-Throttle-Turn. There’s a loop (or used to be) near me called “Harry S” (Truman Drive) a couple of long sweeping right turns, banked a little -a good place on the street to get the knee down.

I found it could be a useful technique.

I abandoned it when it betrayed me on the final left turn at home that day after many laps on Harry S- I lost the front trailing the brakes off (something slippery? - I felt it go- almost in slow motion) and broke my foot peg and a small foot bone.

I found that the technique wasn’t at fault, my timing and application of it was, but it as a trained reaction contributed to the inability to recover after I felt the front bite again when the brakes released and the wheel roll. I needed that tire to press on the pavement and when the throttle was applied there wasn’t enough front traction to keep the rubber side down.

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Brake-Throttle-Turn implies, as a sequence of actions a passage of time. With the passage of time there also means that there is an interval between each successive action.

 

We can agree that for any rider, bike, weight, lean angle, etc (add specifics) there is a maximum speed at which a turn could be negotiated successfully without running wide off or off track.

 

It is more erratic to reduce speed only to add back what you have scrubbed off. From this viewpoint this technique has limited benefits for a track day rider. But I believe that in a race could serve a strategic or tactical purpose. For example: inside block-passing or as a tight group of 3 vying for position.

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"Brake-gas-turn, the XX-tuner's mantra". 

"Brake early, get comfortable, then drive through the corner. Not accelerate, drive through."

 

 

Personally, I can turn on a steady throttle when corners are wide open and I do not have to lean a lot, but the moment my pace starts to go up a bit and/or visibility is limited (not a track issue, but I am a street rider), I either turn on a trailing throttle or with the brakes on. I used to be hard on the brakes, but now I am happy as long as I am trailing off speed when I turn in.

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28 minutes ago, faffi said:

"Brake-gas-turn, the XX-tuner's mantra". 

"Brake early, get comfortable, then drive through the corner. Not accelerate, drive through."

 

 

Personally, I can turn on a steady throttle when corners are wide open and I do not have to lean a lot, but the moment my pace starts to go up a bit and/or visibility is limited (not a track issue, but I am a street rider), I either turn on a trailing throttle or with the brakes on. I used to be hard on the brakes, but now I am happy as long as I am trailing off speed when I turn in.

Curious about your use of this technique. Please share.

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Before I try to explain, it may be important to know that other than basic, mandatory training in order to obtain my licence, little if anything was educated in the form of riding techniques. I had 7 riding lessons back in 1980, where I had to demonstrate I could ride fast and slow slalom, turn feet-up inside a virtual garage, stop safely during emergency braking and act responsibly in traffic. It was mostly "do that" rather than "this is the way to do that". You either figured it out, or you flunked.

What little I did know came from bicycling. I cycled about 5 miles per day riding to school, in all kinds of weather. Anything from dry and warm tarmac to 1 foot deep snow to black ice. I also got hold of a pamphlet that explained the importance of taking as wide an arch as possible around every corner in order to be able to see as far ahead as possible. That was basically it.

So, to the turn-in on the brakes. Nobody ever told me, it just what I did from the first corner I entered back in the spring of 1980. Some may remember that in 2011/2012, I tried to re-educate myself to setting my entry speed early. It was v-e-r-y difficult, and I also felt unsafe. Enough so that I ride poorly enough to experience slides at a slow pace; I was tense. After lots of practice, I finally came to the point where I could follow this technique and feel OK with it. And I sometimes do this when I trundle along. But it still leaves me in the dark regarding how much front end grip I have at my disposal due to less feedback through the bars.

Another issue is that if I have to brake mid-corner - which one can say would be because of speed being too high for the conditions - it is a huge benefit to already having loaded the front tire and brakes. Especially for a ham-fisted rider like me. 

Other than that, front end load is my friend. I do not mind getting on the brakes mid-corner. I do not mind braking all around a corner (because I went in too hot). I do not mind adding more lean while already leaned over and on the brakes. Although probably the wrong thing(s) to do, it works for me. Even on ice or in snow, I primarily rely on the front brake. It used to be solely, but now I have trained myself to also use the rear brake when it feels correct, alone or together with the front. What if the front locks up? Release and reapply. 

Long reply, this, and perhaps without giving you a good answer. But basically I do it because it feels right, always did. To me. Just as doing my braking - or slowing - upright feels unnatural. To me. 

 

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On ‎9‎/‎17‎/‎2019 at 3:12 PM, trueblue550 said:

The very first thing I learned from Keith was from that classroom scene in the TOTW II video: "Once the throttle is cracked open, it is rolled on evenly, smoothly and constantly throughout remainder of turn." In my opinion, when I feel I need maintenance throttle it is because my entry speed was too low. I can't imagine getting on the gas before turn in. In some sections like turns 4/5/6 at SOW, I may not ever close the throttle all the way but just stop rolling on while turning.

Well said.

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Ok @faffi. I understand. I think I took a break from the forum around that time but I did see a few posts from you that puzzled me. You filled in the blanks.

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16 hours ago, Jaybird180 said:

Ok @faffi. I understand. I think I took a break from the forum around that time but I did see a few posts from you that puzzled me. You filled in the blanks.

There is good info on this in TOTWII, Chapter 25, Traction, there is a section about "traction riders" and if you read that whole chapter it gives a nice description of how different riders use and perceive traction, and the pros and cons of these different approaches, I think both you and Faffi will find it very interesting.

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