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Steve M

Trail Braking

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OK - Tell the truth. Do you trail brake, and under what circumstances do you do so? Also, do you think there are certain circumstances that warrant trailing the brakes into a turn, and are there types of turns that lend themselves to trail braking (more than others)?

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That's the same as asking someone if they counter steer. Everyone trail brakes to some degree almost everytime they use the brake(s). The question on using it as a technique is different. If you ask: What can be gained and what can be lost you would come up with two columns of information, the potential pluses and minuses. Make a list of the positives and the negatives of trail braking then we can look it over

 

Keith

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Ok I'll start the list.

 

On the plus side - Trail braking allows you to extend your braking zone further into the corner. This allows you to brake later/deeper and is very usefull when passing another rider.

 

In the minus side - You can not get on the gas as early if you are trail braking.

 

One rule of thumb I have heard for trail braking that makes pretty good sense is... Never trail brake into a corner that is followed by a long strait. Obviously turn 9 on the big track at willow is probably an excption to this as I think pretty much everyone trail braks to some degree there, but it seems like a pretty good rule of thumb.

 

By the way, yes I do trail brake in some corners.

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That sounds like good advice. I have found that in turns where I need a really quick turn trail braking does not seem helpful (say turn 11 at T-Hill). In fact, I think a lot of guys low side there because they simply over-load the front trying to trail it in. To me, it is much quicker through the turn if you complete your braking and flick the bike very quickly. This seems to agree with Stuman's comment regarding long straights (there is a long straignt after the 11-13 chicane).

 

I have also found that trail braking works really well at Button Willow AFM turn (hugely decreasing radius). It seems that you can go much faster and deeper by gently releasing brake as you go into the turn. Not to mention the fact that you don't, you have a better chance of getting passed going in to the turn.

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I have also found that trail braking works really well at Button Willow AFM turn (hugely decreasing radius).  It seems that you can go much faster and deeper by gently releasing brake as you go into the turn.  Not to mention the fact that you don't, you have a better chance of getting passed going in to the turn.

 

That's a turn I like to get all my braking done just in time, then be on the gas early enough to keep the front end pleasantly loaded, gradually increasing lean to get the best drive into the esses. The only time I trail brake there is when I'm gonzo passing someone up the inside, and that's a sketch move anyway.

 

There are a lot of people that get confused by that turn, but to me it seems natural and easy despite the relative lack of (or constantly changing) reference points. The width of it makes for some very amusing passing possibilities and you follow people getting lost there in their own mental maps.

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So to weigh in... My braking into/through a corner is very progressive.

 

I'll get on the brakes and steadily while quickly, apply more and more brake until I'm at my max braking power for that corner (which is still only about 75-80% of what could actually be achieved by the brakes before catapulting me off). Anyhow, once I've shaved off most of my speed, I begin releasing the brake as I go INTO the corner. I'm still braking but decreasing the amount of braking up to the apex of the turn. At that point, the bike feels 'neutral' and I get back on the gas in an almost seamless transition.

 

Releasing the brakes in the turn helps me maintain some compliance in the front end, while getting more and more weight on the back in preparation for getting on the gas.

 

So there... That's my corner (in the ideal situation).

 

A mentor once told me that trail braking to the apex was the fastest way around the track, and to learn it required a lot of patience and a good set of leathers...

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I'm still braking but decreasing the amount of braking up to the apex of the turn.

So Jeff, You trail brake to the apex in most-every turn?

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Carrying the brakes late into the turn has messed up a lot of guys, and their chances of winning races. 2 that come to mind are Duhamel tossing it in front of Scott Russell at Daytona, and Kurtis doing the same thing in front of Mladin at Mid-Ohio this year.

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I have been pursuing the theory behind this question and was reminded (TotW vol.II) of the idea that one way is to taper off the throttle instead of chopping it to set your entry speed; the benefit is "lowering the voltage" associated with SR's and allowing you to get back on the gas sooner.

 

I have to admit that this past season, I started hard charging turns to get my lap times down. The more I tried this, the more the front end became unstable and my cone of vision shrunk to the size of a doughnut hole. By the way, my lap times also went up.

 

I am fixated on improving lap times but I am going "back to school" next year to get this right.

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I made big gains on my 125 late this season by going in deeper... REALLY deep before applying the brakes. This meant I was trail braking a bit more. The bike seems easier to steer/turn in with the brakes applied. The thing I found was that with both lean and brakes you scrub speed in a hurry. Getting off the brakes aand back on the gas early is key.

 

This means things happen quickly. no time is spent off the brakes and trailing throttle-something I used to do a fair bit of.

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Earlier I mentioned starting a list of things that are pluses and minuses on trailbraking. I guess yo guys are going to make me work this all out on my own aren't you. Let's see some data and be a little more scientific about it and then decide if and when the technique applies.

 

I gotta go up and do the DOc Wong events this weekend but I'm hoping to get a list from you guys and next week start to pan it out for the nuggets of wisdom we can find.

 

Keith

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OK,

 

Pros:

 

Able to brake later to make passes

Bike turns in better (geometry)

Speed is scrubbed very quickly

Less time is wasted trailing throttle (not accomplishing anything)

If it's done right, you can drop time from your laps

 

Cons:

 

Less traction available, especially for mid corner corrections/evasive manouvres

Speed is scrubbed very quickly

rider inputs are closer together, less time to do everything

Harder to get on the gas early

Mid corner speed may suffer

If it eats up to much focus, lap times could go up or you could crash

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Paab,

 

Good start to the list.

 

As for me, I think overtaking and defending are probably the best reasons for trail braking but I do not understand "Bike turns in better (geometry)". Maybe it is just certain corners or maybe it is my application of the controls, but when I make turn inputs while braking, my bike feels heavy and I do not feel like I can turn it as quickly, or get on the gas as soon, thus not allowing me to keep a tight line. Like you pointed out, it seems like when I try to carry more speed at the entry of the turn I often sacrifice corner speed and the all important exit speed.

 

A couple of things I would like to add:

 

Stability: While on the brakes the front is loaded (the suspension is not balanced) and the bike is less stable.

Suspension: While on the brakes the suspension is compressed less compliant and less able to deal with bumps.

Lean angle: The slower I turn the bike, the more lean angle is required (all else being equal).

Radius: The slower I turn the bike the tighter the radius.

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When you are on the brakes, rake and trail are reduced. It has to be easier to turn in under these conditions. If not, perhaps you're tense on the bars and fighting the countersteer thing?

 

CON: It's hard to relax when you're hard on the brakes.

 

Definitely true about the suspension/bumps...

 

If you turn in slower, isn't the radius bigger? That's why you have to lean more. To try to tighten it up.

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I agree with Steve on the point about the bike feeling heavy when trying to turn it on the brakes as do most people I have spoken with regarding this subject. I haven?t had anyone tell me that there bike turns quicker and feels like it turns in easier when on the brakes. I know in theory it seem like it should be easier to turn because the forks are compressed, but most people will tell you that the bike feels heavy when you try to turn it on the brakes. I think this is probably due to the extra load and friction from the front tire.

 

One thing I think should be added to the Con list would be that you CANNOT turn the bike as fast when you trail brake. You have to turn it slower because if you don?t you could loose the front. This I think is the tricky part about trail braking. If you are not using the front brake it?s practically impossible to turn the bike too quick. This is not the case when trail braking, you can easily loose the front if you turn the bike a little too quick or use a little too much brake, it?s a very fine line.

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One other thing I just thought of ?

 

All bikes have a tendency to stand up when you use the front brake while leaned over. Some do it less then others but all bikes will want to stand up if you apply the brake while leaned over.

 

When trail braking you are fighting the bike's tendency to stand up. You have to push harder to keep the bike turned if you?re on the brakes. I think this may help explain why most people feel the bike is heavy when trying to turn it on the brakes.

 

So I guess there?s one more for the con side of things? You have to push harder to get the bike to turn.

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It looks like the con list is growing faster than the pro list so I will through a "potential" pro out for discussion.

 

Consider the attitude of the bike when under braking. The front is loaded and the front suspension compressed. If you wait until you are fully off the brakes before you turn the bike, the suspension unloads, only to load again (from cornering forces). It would seem theoretically possible to begin the turn while the suspension is still compressed (to some degree) while trailing off the brakes. The desired effect would be to eliminate the additional compression from cornering forces. Thoughts?

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Well said, that's what I was getting at when I said the bike turns in better. I don't have a problem leaning it quickly on the brakes, and it's more stable/smoother for the reasons you stated.

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So, I was chatting with Tony Faole (suspension guru - he is to motorcycle suspension what Keith is to motorcycle riding) today and I presented this question to him. He agrees with us on this point (balancing the suspension between braking and turning forces). Of course, this may not be the fastest way through every turn, and the line you take through a given turn will vary depending if and how much you brake [into the turn].

 

Tony also explained why the bike feels so heavy while on the brakes but I am afraid that if I try to repeat what he said I will mess it up. What I do know is that the forces required to turn the bike are impacted by the forces (inertial forces?) trying to keep the bike going in a straight line combined with weight transfer from heavy braking.

 

So, there appears to be a trade-off. If you trail the brakes into the turn, you will not be able to turn the bike as quickly, thus you may not be able to hold the line you want, you may need more lean angle, and sacrifice some mid corner speed (not to mention all the other cons we identified above). However, you may gain a higher entry speed, and you may be able to maintain a more stable suspension.

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So Jeff, You trail brake to the apex in most-every turn?

In most, yes to some small degree.

 

When I first started racing, I was running completely off of knowledge based on 20 years of general "riding" and then TOTW I&II knowledge of how things "really" work.

 

With that, I would do 95-100% of my braking while completely verticle and then get back on the gas while entering the corner. This worked quite well, but went against much of the wisdom which a few of my mentors had.

 

I think that I could likely go just as fast if not faster while doing most of my braking upright.

 

This became evident last year when on my brand new bike I was single-finger braking (another practice I've since broken) and while downshifting/blipping/braking going into T1 at Blackhawk Farms, I blipped for 2nd gear (my final downshift) and my finger slipped off the brake lever.

 

The bike shot forward because it was high in the powerband. All of the input coming to me at the same time was too much to handle, and instinct said "stay on the gas and get THROUGH the corner". I did, and the result was perfect.

 

It proved to me that I was braking WAY too hard, too soon and too much...

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Ha! That's a great trick for finding out you're braking to much. I will often try to let off the brakes a second sooner than normal. 9 times out of ten I can still hold the line, and I carry more speed.

 

Then I move my brake marker closer.

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One of the things that Tony Foale brought up during his clinic/lecture at Doc Wongs was that

as you brake you actually increase the trail up to (I think) 20mm. This could be another reason that they feel a bit heavy at the bars under braking and turning.

 

The thing on the bike comng up if you brake in turns was something that I asked him about as well. Basically the contact patch's position is trying to steer the tire inwards which countersteers the bike upwards. The contact patch is on the inside of the center line of the bike is why.

 

Keith

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I always ask a couple questions when peaple tell me about the benifits of trial brakeing.

 

Can you go fast enough in a turn to slide the front tire? most will answer yes.

 

If you can slide the front with speed how much traction is left for brakeing? None

 

if you have traction to be using the brakes then you have already slowed too much.

 

it is posible to let go of the brakes and turn without unloading the front, you must turn very

 

quick 1 or 2 tenths and do it just as you release the brake. it takes alot of practice to get the

 

timming down, but once you get it tucking the front all but disapears as a possible problem.

 

Will

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There's a problem in your logic ballistic. You assume that just because someone is pushing the front, that they have reached maximum velocity for the turn. NO WAY! I teach at a lot of trackdays, and I see people sliding things all over the place going SLOW! They just suck, or they are trying to hard and are too tense on the bars, etc. Anyway sliding is far from indicating that you have reached maximum speed.

 

Also, if you are letting go of the brakes late enough to keep the front end from rising, then you ARE trail braking, no question. You likely can release the brake before reaching max lean and therefore sliding the front is irrelevant because you off the brakes by then anyway.

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There's a problem in your logic ballistic. You assume that just because someone is pushing the front, that they have reached maximum velocity for the turn. NO WAY! I teach at a lot of trackdays, and I see people sliding things all over the place going SLOW! They just suck, or they are trying to hard and are too tense on the bars, etc. Anyway sliding is far from indicating that you have reached maximum speed.

 

Paab - If the front tire is sliding, for all intents and purposes it has used up all available traction. At some level of riding (like GP) riders can and do purposely push or slide their front tires. Keith has some discussion on this in Twist II Chapter 17 (I think - I don't have the book in front of me at the moment). For the rest of us mortals though, attempting to brake while the front is pushing is ?a very delicate business?.

 

The point is, the rider sliding his front (regardless of speed) has indeed reached his limit of traction (and therefore speed) for that particular turn, on that bike, on those tires and at that very point in time. Can someone else go through the same turn much faster? Sure. The same rider may go through the turn much faster on the next lap. But at the moment the tire begins sliding, for all intents and purposes there is no more available traction remaining for braking or additional lean.

 

Also, if you are letting go of the brakes late enough to keep the front end from rising, then you ARE trail braking, no question. You likely can release the brake before reaching max lean and therefore sliding the front is irrelevant because you off the brakes by then anyway.

There may be a miscommunication here. I think we need to define the term trail braking. To me, trailing the brakes means that you continue on the brakes after you have made a steering input (I checked this on an unrelated website and it seems to be a consistent definition). Certainly, one must always release the brakes smoothly so as not to unnecessarily upset the suspension. However, this can be done very quickly, and so long as it is completed prior to the steering input, I do not think you are trailing the brakes.

 

So, can you trail the brakes deep into the turn? Sure. Can you finish your braking while in a straight line, then turn the bike? Sure. You have identified the very purpose of the original post. Which do you do, and why? Or, do you trail for some turns and not others? Do you trail in different circumstances? I am interested to hear what you do and why you do it.

 

By the way, Ballistic is insanely fast, and typically does not trail brake. He instead finishes his braking in a straight line (presumable right to the limit of traction), then turns the bike extremely quickly (again, presumably at the limit of traction). This technique works very well for him as he just crushed the all time lap record at Streets of Willow Springs on (I think) a production 636 with DOT tires. I hope you get a chance to ride with him some time ? it is a real treat to watch ? so long as you can keep him in view (which is no small task).

 

Steve

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