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Discussion Starter #1
The usual recommendation when people complain that they're getting transmission jerks when opening or closing the throttle, is (assuming there's no mechanical problem) to practice smooth throttle inputs. That's sound advice of course, for various reasons besides off-idle jerks, but there's a problem that no amount of smoothness can address, as far as I can tell.

Smooth throttle inputs essentially boil down to (sufficiently) slow throttle inputs. In the context of throttle jerkiness, the critical phase, where smoothness is required, is while the engine is crossing the transition between braking and acceleration. Imagine opening the throttle "infinitely slow" while engine-braking. At some point the engine would cease braking and the motorcycle would coast at constant speed. At that point, any more throttle would cause the engine/transmission to freewheel until the lower run of the chain goes slack and the upper run goes tight, and all the gears shift a bit and after that point you start to accelerate. So during that transition, any more than absolutely necessary throttle will just allow the engine to pick up more speed while freewheeling and increase the jerk you'll get once the chain tightens again.

Assuming that is correct, one necessarily has to be slow. Ideally one could quickly open the throttle up to the critical point, then slow down until the transition is complete and then speed up again. That is perhaps possible to some extent when high up in the rev band, as then the point of torque reversal is far from idle. When going relatively slow though, that point is right off-idle and the only way I can avoid a jerk is to open the throttle slowly until I'm accelerating, which again often causes me to apply power later than intended. It's not a matter of technique, as far as I can tell, as I can apply throttle at various speeds, causing jerks of various intensities from silky smooth, to moderate, to jarring. It's just that, if you want to be smooth, you need to be slow.

I can see only one way out of this: opening the throttle prematurely, compensating for the delay until acceleration sets in. The problem there is that, while one is prematurely opening the throttle engine braking diminishes and one has to take that into account as well, to avoid overshooting your intended speed. Perhaps the necessary precision can be achieved through practice, but a different approach would be to overlap throttle roll-on and roll-off with braking. So when initiating braking for instance, instead of first fully closing the throttle and then applying the brakes, one could start applying the brakes either before or while closing the throttle, as needed, so that deceleration starts before engine braking sets in. Conversely, when accelerating, one can start opening the throttle prematurely, before fully releasing the brakes. The goal is to be able to cross the jerky-prone transition preemptively and "at leisure" while using the brake to control speed.

Well that is the idea. I've been experimenting for a while now with this and it sort of works. Much of the above happens semi-subconsciously now and I sometimes deviate from the strategy. For instance, when I want to reduce speed but anticipate that I'll soon want to accelerate again, I don't bother fully closing the throttle. Instead I keep it open at "maintenance throttle" so that it doesn't appreciably fight against the brake but doesn't help it either, which allows me to accelerate again or brake further if necessary without delay. In a turn, I brake before the turn as normal, but while releasing the brake I start applying throttle, so that by the time the brake is fully released, I'm already at maintenance throttle, going at constant speed and able to apply throttle at will without the possibility of a jerk.

I mention all this not as a great discovery, but because I haven't found it mentioned explicitly anywhere, with the exception of a book, where it was mentioned fleetingly, in the context of trail braking. I was wondering therefore, whether the more experienced riders among us use this technique, or something similar, either consciously or subconsciously, or whether they can think of any reasons to advise against it.
 

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I want Rossi to fuck my ass...
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So when initiating braking for instance, instead of first fully closing the throttle and then applying the brakes, one could start applying the brakes either before or while closing the throttle, as needed, so that deceleration starts before engine braking sets in.
This was my interpretation of trail braking when I was learning. Hold throttle til you need to brake, no engine braking or coasting, and while still braking, blip the throttle and downshift. My understanding, either the throttle is on, or the brakes. No coasting allowed

Great read. I enjoy seeing your mind at work
 

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Guess I'm one of those who use "maintenance throttle" regularly. Almost never get off the throttle completely going into a turn, it's far too unsettling. I'm only consciously off the throttle completely at a full stop. Of course, now that I say that I'm probably going to find myself contradicting that statement. :lol:

The one consequence of this is during braking the rear will be pushing forward while the front is pushing back, moving even more weight to the front and extending the rear shock further. My guess is this is shortening the wheelbase just a tiny bit, which along with the forward shift in weight changes the turning characteristics of the bike slightly. Typically I keep the throttle cracked juuuuust enough to avoid chopping off while initially braking hard but smooth then slooowly trailing off the brake and bringing back the throttle. I also use the throttle to control my line to an extent, easing off a tiny bit to drop in and vice versa.

Chopping off the throttle going into a turn is one of the worst feelings!

At low speeds, I use the clutch liberally to smooth things out.

Not among the "more experienced riders" here but 3+ years riding every chance I get and at least 30k - not 30k highway miles but 30k street, traffic & twisties, with clear objectives for improving and constantly pushing myself to improve my technique.

Still so much to learn - thanks for posting this though I love exploring riding theory and hearing how other people accomplish the same things I'm striving to improve. Nothing replaces good old practice, but I find a lot of benefit from being conscious of my technique, reading and mentally preparing/practicing as well.
 

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Discussion Starter #5
The one consequence of this is during braking the rear will be pushing forward while the front is pushing back, moving even more weight to the front and extending the rear shock further. My guess is this is shortening the wheelbase just a tiny bit, which along with the forward shift in weight changes the turning characteristics of the bike slightly. Typically I keep the throttle cracked juuuuust enough to avoid chopping off while initially braking hard but smooth then slooowly trailing off the brake and bringing back the throttle. I also use the throttle to control my line to an extent, easing off a tiny bit to drop in and vice versa.
You address your own concern. There are 3 states the engine can be in with regards to acceleration: braking the vehicle, accelerating it or neither. If you brake with a completely closed throttle, most of the braking comes from the brakes and a relatively small part (depending on engine speed of course) comes from the engine. The latter part is essentially indistinguishable from rear brake application, so you can keep the engine at more or less "neutral" revs and control your deceleration with just the brakes; the chassis won't "feel" any difference. There's no reason to keep the throttle open enough for the engine to want to accelerate appreciably.

By the way, the throttle opening at which the engine is neutral in terms of acceleration, is the throttle it would take to achieve your current engine speed, if you were in neutral. That's the fuel the engine needs to make the power to get itself going at that speed. Any less than that and it "wants" to go slower, draging the rear wheel with it. The converse is also true of course. The interesting thing is that the point depends solely on your engine speed, not on the total load/vehicle speed. (I didn't realize that at first and a friend had to set me straight.) Perhaps that partly explains why people generally report that throttle jerks are worse when at lower engine speeds, as then the critical throttle opening is closer to fully closed throttle and harder to control. Another reason, probably more important, is that the transitional phase is longer time-wise, giving you more time to open the throttle further and requiring slower/smoother control.

Question: Is this in regards to riding on the track or street?
I was intentionally vague in that respect. From a purely technical aspect, the intended effects here are minimization of chassis disturbance, hence minimization of geometry changes, which can be unsetling if not anticipated or compensated for and minimization of tire load variation, which is to the benefit of traction. (Side benefits might include comfort improvement.) One can argue that this is beneficial, both at the street and at the track. You could say that at the track, the above goals may be critical, since you spend so much time close to the limits of traction, but then again we clearly spend some time on the limits of traction on the street too. How can all those lowsides be explained otherwise? And although it may not be very often, the consequences can be far worse.

Having better and more precisie control of your bike can also be said to be a good thing in both scenarios. Additionally, on the street there might be other applications for such a technique, since it's much more often that you'll want to shift from your current constant speed to a lower one, then accelerate again, as for instance when approaching an intersection, where you want to check even though you may have the right of way. In such cases, the benefits are more a matter of comfort of course (or enjoyment, if jerks annoy you).
 

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Let's deconstruct this a bit, and look at MotoGP riders, who arguably are the best moto riders in the world. They stay in full throttle as long as possible, and then brake, with a good deal of their braking done while turning, and often with the rear wheel in the air. Do you think any of them are worrying about throttle/brake simultaneous application? They aren't. It's not an issue. Smoothness comes from slow hands and attention.

Personally, I think anyone who tries to simultaneously use both is making a huge mistake.

How are lowsides explained? There are several reasons, but the primary cause is probably a combo of bad tires, shitty suspension, too much speed, and mostly not loading the front tire. Ideally we trail brake almost all the way or all the way to the apex of the corner. When you back out of braking while leaned fully over, you lessen front tire grip. Trail braking makes it easier to turn and keeps the front tire loaded. Remove the load, the front goes away.

The most vulnerable and dangerous part of any corner is the time spent at maximum lean. That's the time when our brake and throttle inputs, and bar inputs need to be the smoothest and least disruptive.
 

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I know things... A lot of things.
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Discussion Starter #7
Smoothness comes from slow hands and attention.
Personally, I think anyone who tries to simultaneously use both is making a huge mistake.
Noted. You may well be right. I didn't intend any of this as advice, rather as an experiment suggested by my assumption that slow inputs and precisely timed inputs are incompatible otherwise. This assumption may well be wrong. I have no way of telling whether MotoGP riders crack the throttle before fully releasing their brakes, during the final couple of seconds of trail braking and furthermore I'm not sure whether that's relevant. For instance MotoGP riders may have electronics to take care of that, or idles raised so high as to make all this irrelevant. I haven't the slightest.

Regarding low-sides, and whatever the ultimate cause for each case, they are a direct result of exceeding the traction capabilities of the tires. I only brought them up as an illustration that optimization of traction can also be beneficial on the street some times, even though one mostly rides well below the limits. I agree that most of the real word low-sides, are not marginal enough to be saved by avoiding a small chassis jerk during a turn, but I assumed that goes without saying and my posts are usually long enough without nit-picking.
 

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Noted. You may well be right. I didn't intend any of this as advice, rather as an experiment suggested by my assumption that slow inputs and precisely timed inputs are incompatible otherwise. This assumption may well be wrong. I have no way of telling whether MotoGP riders crack the throttle before fully releasing their brakes, during the final couple of seconds of trail braking and furthermore I'm not sure whether that's relevant. For instance MotoGP riders may have electronics to take care of that, or idles raised so high as to make all this irrelevant. I haven't the slightest.

Regarding low-sides, and whatever the ultimate cause for each case, they are a direct result of exceeding the traction capabilities of the tires. I only brought them up as an illustration that optimization of traction can also be beneficial on the street some times, even though one mostly rides well below the limits. I agree that most of the real word low-sides, are not marginal enough to be saved by avoiding a small chassis jerk during a turn, but I assumed that goes without saying and my posts are usually long enough without nit-picking.
Some good points. As to the MotoGP guys, they are off the throttle and braking with the rear wheel in the air LONG before the apex, then tapering off the braking to the apex. Upsetting the bike by adding throttle is not something they do. You can see throttle/brake readouts on the broadcasts.

Yes, lowsides are due to traction or lack of it, I listed specific cases that may contribute to that or help it.

You're thorough in your posts, nothing wrong with that.
 

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Most people who complain about jerkiness on a modern sport bike are riding it like a cruiser and have the RPMs too low. As long as you keep the engine singing (assuming the chain is adjusted correctly), there's not a noticeable jerk.
 

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smooth throttle is a "product" of proper body position.you need to "anchor" your body on the bike so that there's no,or almost none,weight on your hands.if you support your weight on your hands your throttle application will be abrupt.inside foot,outside thigh and core muscles should be engaged. "when cracking the throttle your hand should be as slow as possible"

from Ken Hill's podcasts. :cheers
 

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smooth throttle is a "product" of proper body position.you need to "anchor" your body on the bike so that there's no,or almost none,weight on your hands.if you support your weight on your hands your throttle application will be abrupt.inside foot,outside thigh and core muscles should be engaged. "when cracking the throttle your hand should be as slow as possible"

from Ken Hill's podcasts. :cheers
Ken knows what he is talking about.
 

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Discussion Starter #12
The point of all this, isn't to substitute smooth inputs. Yes a certain amount of practice, concentration and proper technique is necessary in order to be smooth, but assume, for the purposes of this discussion, that you have a bionic, servo-controlled wrist and can be arbitrarily precise. If "when cracking the throttle your hand should be as slow as possible", then that means that you either have to crack the throttle well in advance of the time you plan on having "maintenance throttle", or miss that point or shock the chassis so as not to. Since well in advance of maintenance throttle you're probably still braking, that would imply the necessity of overlap.

Then there's also the consideration of whether it is not also beneficial to avoid having to be very accurate at the point when it's most critical, since we're talking about human (as opposed to electronic) control strategies and concentration is a very scarce resource. What I mean by this, is that I find it easier to crack the throttle very slowly and well in advance of of my brakes-off point, when I don't have to worry about being too slow about it, as opposed to having to execute a precise 1-sec roll-on, 1 second before the time I'd like to be at maintenance throttle. On the other hand, it does rob me of some concentration during the final stages of braking (although not much as it doesn't have to be precisely timed) but that might be a problem in situations where braking would be more critical. That's the problem with trying new techniques: it's hard to know whether they'll work or not and if they turn out not to, you'll have to make the extra effort to unlearn them too.

Regarding the pros, some preliminary research seems to indicate that they're running pretty high idle speeds. Several sources mentioned 3000rpms for (older) GP and GP replica machines and it seems that their ECUs can probably further vary the idle speed depending on the riding conditions. I assume the primary point of all that, is to limit rear wheel hopping/sliding due to engine braking, when there's zero load on it due to front wheel normal braking, but the fact is that, whether wanted/intentional or not, it also essentially keeps the throttle cracked when the rider closes it.
 

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The point of all this, isn't to substitute smooth inputs. Yes a certain amount of practice, concentration and proper technique is necessary in order to be smooth, but assume, for the purposes of this discussion, that you have a bionic, servo-controlled wrist and can be arbitrarily precise. If "when cracking the throttle your hand should be as slow as possible", then that means that you either have to crack the throttle well in advance of the time you plan on having "maintenance throttle", or miss that point or shock the chassis so as not to. Since well in advance of maintenance throttle you're probably still braking, that would imply the necessity of overlap.

Then there's also the consideration of whether it is not also beneficial to avoid having to be very accurate at the point when it's most critical, since we're talking about human (as opposed to electronic) control strategies and concentration is a very scarce resource. What I mean by this, is that I find it easier to crack the throttle very slowly and well in advance of of my brakes-off point, when I don't have to worry about being too slow about it, as opposed to having to execute a precise 1-sec roll-on, 1 second before the time I'd like to be at maintenance throttle. On the other hand, it does rob me of some concentration during the final stages of braking (although not much as it doesn't have to be precisely timed) but that might be a problem in situations where braking would be more critical. That's the problem with trying new techniques: it's hard to know whether they'll work or not and if they turn out not to, you'll have to make the extra effort to unlearn them too.

Regarding the pros, some preliminary research seems to indicate that they're running pretty high idle speeds. Several sources mentioned 3000rpms for (older) GP and GP replica machines and it seems that their ECUs can probably further vary the idle speed depending on the riding conditions. I assume the primary point of all that, is to limit rear wheel hopping/sliding due to engine braking, when there's zero load on it due to front wheel normal braking, but the fact is that, whether wanted/intentional or not, it also essentially keeps the throttle cracked when the rider closes it.
Nobody runs a bike down to 3000 rpm in corners (at racing level). The point of using gearing in a corner is to have the bike in the proper gear to give maximum acceleration at the exit of the corner. That's way above 3,000 rpm. There is engine control for max braking, but you don't see that at the very end of trail braking. The fuel maps are basically almost zero there.

For the pros, cracking the throttle on ( the reason for this is to load the rear tire prior to more throttle, just as very slight braking initiates brake maneuvers) occurs at the moment they begin to take lean angle away. At max lean angle you are at maximum vulnerability and adding throttle is fraught with risk. See your exit, take lean angle away, add throttle. That's the mantra. If you use maintenance throttle through the corner, you still crack it further when you take lean angle away.

I suspect you're way overthinking this. Pros don't have a problem with smoothness, nor is overlap a problem. The sport pretty much consists of the last fifty feet to the apex and the first fifty feet beyond it. That's where the crucial control work is done.

I'm a long time rider/racer, and have both studied with Ken Hill and worked with him at the track. I also am an instructor.
 

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Good points Ernie.
Going back to Ken, there's a slowest point in every corner :the end of braking zone (so you have exit direction) and the beginning of the acceleration zone. At this point you have your maximum lean angle. So there's a distinction between braking and throttle. There may be places where overlapping could become handy but ,to the extend of my understanding, the rule is trail-brake for direction and then crack the throttle to load the tire and suspension,in other words get them ready for the hard acceleration part.
 

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Discussion Starter #15
I never said anything about riding at 3000 rpm, I only said the idle speed seems to be set there for relatively modern racing machines. No matter what the technical details, the idle speed basically corresponds to how open your throttle valves are when the throttle grip is fully closed, so there's no essential difference between keeping the throttle open a bit while braking, or setting your idle speed high. In the latter case it's just that the throttle stop screw or ISC valve does the opening for you.

Regarding cracking the throttle while turning, there seems to be a misunderstanding. I'll try to avoid both terminology and issues of style here. Imagine entering a turn with the brakes engaged and the throttle closed. Your braking force is the sum of the forces coming from the calipers and from the engine. Now you gradually release the brakes as dictated by your style. When you've fully released the brakes, you're still braking due to your engine. Depending on your engine specs and engine speed you might be braking a lot. In order to stop decelerating, you need to open the throttle a bit so as to give your motor enough fuel to keep its speed constant.

Whether you want that or not is a matter of style. Theoretically, when you're at full lean you'd like to have zero braking or acceleration force at the tire, but theory is not everything. My point is that having the throttle open, in the way I have in mind once the brakes are fully released does not necessarily mean you're going to be accelerating; it means you're not going to be braking. Similarly, having the throttle open while braking, does not mean your engine is going to be fighting the brakes; it means the engine won't be helping them.
 

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I never said anything about riding at 3000 rpm, I only said the idle speed seems to be set there for relatively modern racing machines. No matter what the technical details, the idle speed basically corresponds to how open your throttle valves are when the throttle grip is fully closed, so there's no essential difference between keeping the throttle open a bit while braking, or setting your idle speed high. In the latter case it's just that the throttle stop screw or ISC valve does the opening for you.



Regarding cracking the throttle while turning, there seems to be a misunderstanding. I'll try to avoid both terminology and issues of style here. Imagine entering a turn with the brakes engaged and the throttle closed. Your braking force is the sum of the forces coming from the calipers and from the engine. Now you gradually release the brakes as dictated by your style. When you've fully released the brakes, you're still braking due to your engine. Depending on your engine specs and engine speed you might be braking a lot. In order to stop decelerating, you need to open the throttle a bit so as to give your motor enough fuel to keep its speed constant.



Whether you want that or not is a matter of style. Theoretically, when you're at full lean you'd like to have zero braking or acceleration force at the tire, but theory is not everything. My point is that having the throttle open, in the way I have in mind once the brakes are fully released does not necessarily mean you're going to be accelerating; it means you're not going to be braking. Similarly, having the throttle open while braking, does not mean your engine is going to be fighting the brakes; it means the engine won't be helping them.

I believe there's more to gain being focused on lean angle,grip level and generally receiving feedback from the motorcycle than having some of your attention stolen for the procedure you describe. And I insist that there's a place for everything . I mean you don't always brake to the apex, you don't always crack the throttle before the apex it is corner type dependent. I would "assume" the same applies to overlapping. There could be a certain corner at a certain track where it would help. But I'm only assuming. It does not feel natural to me , I'm not saying it is a wrong technique.
 

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Something else to consider is consistency and repeatability.are you sure you can crack the throttle while braking the same amount every single time? Engine braking is the same every time and that gives a solid base to start from. I'm saying that because trail braking is mainly used for directional purposes . So it would seem wise to raise the idle speed if that makes you feel better than trying to exactly repeat yourself every time and consume attention at the most critical phase of cornering .
 

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When you've fully released the brakes, you're still braking due to your engine.
Once you fully release the brakes (after trail braking) to set final corner speed you immediately get back on the throttle to maintain speed and prepare to accelerate off the corner. The only engine braking might happen within that fraction of a fraction of a second it takes for a human to physically release the brake lever and get back to twisting the throttle. Racers and trackday goers account for that very short time period whether they know it or do it subconsciously. It's done on the street as well to a much lessor degree. Not many people enjoy the feeling of freewheeling into any turn.
 

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MotoGP bikes have different settings for different idle speeds for different applications. It's a touch of a button, just like launch control and pit speed. If they need to have the idle raised the mechanics and engineers take care of all that per rider request.
@Carnage good points
 

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Some good points in this thread... However, MotoGP riders (as well as a lot of WSBK riders) do use both throttle and brake at the same time. Casey Stoner was a very big proponent of that, same with Nicky Hayden, and now Marc Marquez.

SportRider did an article on Stoner and the way he did it, and it was an amazing read.

However, here is what I suggest for track, specifically. Raise your idle to 2,500rpm. Then, brake until you are at the entry speed you need for your corner. This could be at the apex, or it could be before. But don't brake because you are scared. Brake because you need to set your corner speed. Once you do that, you will know when to open the throttle, and whether to use maintenence throttle or not.

I am pretty confident in saying that 99% or riders do not need to worry about using both brake and throttle to smooth things out, and just need to worry about being smoother themselves.

A lot of on/off throttle jerkiness comes from a lack of skill and right hand control, that is all, nothing more.
 
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