Trail braking timing question

[LAS1000RR]

I just attended the two day camp (level 1 and 2) at Willow Springs, which was phenomenal. I was amazed at how much faster I got in two days. A question about trail braking:

In class, we looked at a graph of racers' braking timing. In the graph, the onset of braking to peak pressure was very fast, almost instantaneous, and the release (if I recall correctly) was about two seconds long.

For the technique, I believe we were told to brake, and then release braking gradually as we leaned the bike and got in on line (so the forks only compress once, first for the braking, which trades off for the compression of the turn). Of course once the bike is leaned and online, we roll on the throttle, smoothly, evenly and constantly, and I think we were told that there is no overlap in brake release and throttle roll on. 

But with the quick turn technique, it would seem that getting the bike online is completed in less than 2 seconds. I could be underestimating the time it takes to lean the bike and get it fully online, and I know they qualified this technique as 'when appropriate', so maybe it only applies to corners which would require about 2 seconds to get online?

If any coaches or students can provide clarification, I'd appreciate it!

[Hotfoot]

There were two parts to "when" to start your roll-on. One part is getting the bike to the desired lean, and the other is getting pointed towards the exit of the turn.

If you think of a longer turn that hooks around, or decreasing radius turn, you can probably picture that you can get to your desired lean very quickly, but might have to wait a bit longer for the bike to come around before you are pointed the direction you want to go. Turns with a fast entry that tighten up at the end are well suited for trailing the brakes in, and for most of those you would have to wait to get pointed to a late apex before rolling on to stabilize the line.

Contrast this to a turn like Turn 10 at Streets, where it is VERY advantageous to get the bike turned quickly and get right back to the gas to minimize the effects of the bumps.

 

[Cobie Fair]

On 3/14/2020 at 1:11 PM, LAS1000RR said:

But with the quick turn technique, it would seem that getting the bike online is completed in less than 2 seconds. I could be underestimating the time it takes to lean the bike and get it fully online, and I know they qualified this technique as 'when appropriate', so maybe it only applies to corners which would require about 2 seconds to get online?

If any coaches or students can provide clarification, I'd appreciate it!

What if the braking were begun when the bike was upright, and trailed off (even the last part) when the bike was leaned over?  

[LAS1000RR]

Hi Cobie. Do you mean braking, leaning on full brake, then trailing off?

[Cobie Fair]

No.  Beginning the braking while upright, then trailing off.  If the bike is turned quicker, the last of the braking, will that need to trail of in relation to the increased lean angle, and ideally be coordinated?

 

[faffi]

If you do all, or the absolute majority of, your braking upright, would that not in most instances require some coasting off the throttle? Or can you go still go directly to maintenance throttle as you initiate, or at least finish, turning in?

[Cobie Fair]

Refresh me, up to what level have you done with us?

[faffi]

That puts me in the spot as I am at level 0 😔

[Apollo]

On 3/14/2020 at 1:11 PM, LAS1000RR said:

In class, we looked at a graph of racers' braking timing. In the graph, the onset of braking to peak pressure was very fast, almost instantaneous, and the release (if I recall correctly) was about two seconds long.

For the technique, I believe we were told to brake, and then release braking gradually as we leaned the bike and got in on line (so the forks only compress once, first for the braking, which trades off for the compression of the turn). Of course once the bike is leaned and online, we roll on the throttle, smoothly, evenly and constantly, and I think we were told that there is no overlap in brake release and throttle roll on. 

But with the quick turn technique, it would seem that getting the bike online is completed in less than 2 seconds. I could be underestimating the time it takes to lean the bike and get it fully online, and I know they qualified this technique as 'when appropriate', so maybe it only applies to corners which would require about 2 seconds to get online?

If any coaches or students can provide clarification, I'd appreciate it!

I think you're getting hung up on the "2 second" window.  I don't think of trail braking as a defined time period. As you said, the issue is about loading the front suspension to not upset the bike. And as Hotfoot said, each corner brings about its own unique features, which will affect trail braking and when you transition to the throttle.

All things the same (body position, etc), for a given lean angle, what happens to your turn radius when you decrease speed or increase speed? Does your turn radius decrease if you only decrease speed and change nothing else?  For example, if you turned in and hit your desired lean angle at 70mph, what would happen to your turn radius if you used maintenance throttle to hold your speed at 70mph and what would happen if you continued to slow down below 70? Even if your rate of lean is what you want, trail braking is yet another component that dictates your turn radius and affects your line. 

For high speed, large radius corners, I will have a longer time and lighter pressure trail brake than I would with a slow, tight radius corner where I will have a higher brake pressure but shorter period of time trailing the brakes.  In terms of traction, your tire has 100% of available traction for a given situation and you're trading that 100% between cornering and braking. The more you're asking of the tire for cornering, the less % you can demand of it in braking. 

Personally, trail braking didn't begin to click until I was riding at an upper intermediate group trackday pace. Initially, I would just lightly trail on the brakes on the run down to the apex to avoid 1) coasting and 2) adding throttle while increasing lean angle. This helped me increase my corner entry speed as I would work on increasing my entry speed so that I didn't feel like I was overslowing by trailing in. Also, I would always have the safety net of the trail braking to scrub speed if I came in slightly faster than I was comfortable with. Eventually, when I would overcook an entry (relative to my abilities), the trail braking started to click as I used more braking force and would feel the bike tighten its line as the speed decreased.

[faffi]

I never learned anything about how to ride when I first took my license in 1980. We had to master tight figure 8s, turn around feet up in a "garage", stop within a certain distance, do a slow and a fast slalom set with cones, plus show we could operate safely in traffic. We were basically told to practice until we mastered everything, but hardly any advice about how to operate the bike.

Personally, I used trail braking from the word go without thinking about it, or even knowing it was a term or technique; It just felt natural. Eight years ago, after joining this forum, I set about learning to set my cornering speed early, and it took me nearly two seasons to feel safe doing it. However, I still feel far more comfortable turning in on the brakes, or at least trailing throttle. Even riding slowly. 

As such, I would much rather brake long, even past the apex, than getting very early on the throttle. Especially around tight bends, where early throttle application tend to make me run wide.

    

[faffi]

Trivia: Kenny Roberts Sr relied on early braking, early throttle. Barry Sheene relied on braking deep and hard, squaring off the corner. Roberts always meant Sheene's style was high risk, because it is easier to lose the front. 

[Keith Code]

On 3/25/2020 at 5:49 AM, faffi said:

If you do all, or the absolute majority of, your braking upright, would that not in most instances require some coasting off the throttle? Or can you go still go directly to maintenance throttle as you initiate, or at least finish, turning in?

First off, how do you define "maintenance throttle"?

Brake release is, as Hotfoot pointed out, corner specific. What the 2 second brake release is, is an average, some longer, some shorter time.

There are a few, but not many, corners where it would take a whole 2 seconds to go from upright to full lean. If you are thinking about then to get back to the gas, that's simple, as soon as the bike is pointed to the apex you intend to hit. If you can get the bike turned, and aimed there, very quickly you now have the opportunity to get back to gas. That could be very early on, well before where you kiss your apex--for some corners.

What that tells us is the quicker the steering is initiated (from full upright to your max lean) the earlier you are releasing the brake. Why? The bike is pointed where you want it to go, no reason to spend more time waiting for it to slow (coasting) you are welcome to get back to gas and stabilize the bike with your great throttle control. Rule of thumb would be: The quicker you steer, the earlier the release.

The other rule of thumb you might consider is: You always trail out the brake whether you are finishing it fully upright or as you lean into the corner. Why? Because your opportunity to get your entry speed right where you want it is easier when you take the time to taper off the brakes rather than just dumping the brake lever quickly.

As an aside, there are definitely corners where you wouldn't call how you brake "trail braking". Rainey corner at Laguna Seca is a good example. You fly int the entry area and need to scrub off say 5 to 10 mph. The brake action is a simple in and out squeeze and release, not abrupt on either end but not long either.

We have video with data showing a very good rider who I'd call a Quick Turn Artist, getting the bike point very early and only losing 1 mph between brake off and gas on and that 1 mph loss was well before the apex.

Keith

 

[faffi]

Thank you for taking the time to explain, Mr Code! It appears clear to me that I likely use the brake as my crutch to cover for lack of other skills and/or fear, depending on the situation. I do taper it off, anything else will upset the bike, but as long as I am braking, or at least slowing, I have confidence in the front end as well as the way the bike will behave.

(By maintenance throttle, I mean enough throttle to maintain the speed I have, stopping the slowing process, but not yet accelerating.) 

Probably of absolutely no interest, but this is me riding down a winding road with an 11% decline. No sign of quick turning or early throttle application.