Trail braking 101
08-12-2010, 09:13 AM
#1
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Trail braking 101
I'm a newly promoted white student, which in my club is the first solo group. In the lower groups we were taught to get the braking done in a straight line. I've been reading various driving books and from what I gather, trail braking is a faster way around the track. In "Going Faster" there is a quote from Dorsey Shrader where he says he couldn't think of a corner where he didn't trail brake. Since I don't want to be a complete "utkinpol", I come to the experts with humility and an open mind. Please help me understand this skill and it's practice. My home track is Summit Point and there are some lower speed turns where I do trail brake but would like your input about stepping up to the higher speed turns. I know one has to be careful with the weight of a Porsche rear end.
08-12-2010, 09:30 AM
#2
Still plays with cars.
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A few comments:
1) Do not contemplate trail braking unless you can come off the brake pedal very smoothly - think "fading off" the brakes.
2) A 911 understeers in low speed corners. Trail braking is a good tool to help rotate the car by shifting the balance towards the front end for more bite on entry and less understeer.
3) In high speed corners, trail braking must be more subtle because a 911 with a good set up is neutral in the fast corners. Done wrong the risk of a spin is greater and you're going a lot faster when you go off
4) Going Faster is a good read but as far as I know, it is oriented to the Skip Barber school cars - single seat formula machines which do not share handling characteristics with the 911.
Best,
1) Do not contemplate trail braking unless you can come off the brake pedal very smoothly - think "fading off" the brakes.
2) A 911 understeers in low speed corners. Trail braking is a good tool to help rotate the car by shifting the balance towards the front end for more bite on entry and less understeer.
3) In high speed corners, trail braking must be more subtle because a 911 with a good set up is neutral in the fast corners. Done wrong the risk of a spin is greater and you're going a lot faster when you go off
4) Going Faster is a good read but as far as I know, it is oriented to the Skip Barber school cars - single seat formula machines which do not share handling characteristics with the 911.
Best,
08-12-2010, 09:34 AM
#3
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i'm no expert but your tires can only give u 100% grip, so if u don't scrub off enough speed in a straight line before you turn in, the lateral energy needed to turn the car on the racing line PLUS the amount of braking you are asking it to do may exceed 100% of the tire's capabilities and you'll get understeer. i think a general rule is u trail brake more in slower corners, and u get off brakes as quickly and smoothly as possible in fast corners (try using left foot if you've been practicing) so u don't lose speed. and now, i leave u to the true experts!
ps. nothing on a race car is isolated, meaning the amount of trail braking u can do is affected by the set up of suspension, tires, brakes, and YOUR abiliities!
ps. nothing on a race car is isolated, meaning the amount of trail braking u can do is affected by the set up of suspension, tires, brakes, and YOUR abiliities!
08-12-2010, 09:40 AM
#4
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+1+1+1 A valuable tool? Yes, just take your time with it. Done clumsily it will just hinder your smoothness, tempo and rhythm. With plenty seat time, feel, and car control skills you can use it to your advantage, just hone all your more basic skills first.
1) Do not contemplate trail braking unless you can come off the brake pedal very smoothly - think "fading off" the brakes.
2) A 911 understeers in low speed corners. Trail braking is a good tool to help rotate the car by shifting the balance towards the front end for more bite on entry and less understeer.
3) In high speed corners, trail braking must be more subtle because a 911 with a good set up is neutral in the fast corners. Done wrong the risk of a spin is greater and you're going a lot faster when you go off
4) Going Faster is a good read but as far as I know, it is oriented to the Skip Barber school cars - single seat formula machines which do not share handling characteristics with the 911.
Best,[/QUOTE]
1) Do not contemplate trail braking unless you can come off the brake pedal very smoothly - think "fading off" the brakes.
2) A 911 understeers in low speed corners. Trail braking is a good tool to help rotate the car by shifting the balance towards the front end for more bite on entry and less understeer.
3) In high speed corners, trail braking must be more subtle because a 911 with a good set up is neutral in the fast corners. Done wrong the risk of a spin is greater and you're going a lot faster when you go off
4) Going Faster is a good read but as far as I know, it is oriented to the Skip Barber school cars - single seat formula machines which do not share handling characteristics with the 911.
Best,[/QUOTE]
08-12-2010, 09:50 AM
#5
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+1 all the above.
No expert at all myself, but I think of trail braking to control the rotation going into and through a cormer.
I know you have been to VIR. Trailbraking into T1 at VIR for example will help you keep some rotation in the car, while you go off the brake and on the throttle. To me it's more about keeping the nose tucked in while keeping just enough rotation and smoothness that it does not keep you from going into the throttle as needed.
my 0.02c...
No expert at all myself, but I think of trail braking to control the rotation going into and through a cormer.
I know you have been to VIR. Trailbraking into T1 at VIR for example will help you keep some rotation in the car, while you go off the brake and on the throttle. To me it's more about keeping the nose tucked in while keeping just enough rotation and smoothness that it does not keep you from going into the throttle as needed.
my 0.02c...
08-12-2010, 10:20 AM
#6
Burning Brakes
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Trail braking is most beneficial in low/mid speed speed turns and can also be used to help rotate the car.Don't forget "lift throttle over-steer" which can be used to rotate the rear end as well.
Think the first low speed esses @ VIR.
High speed sweepers... for me it seems best to get braking done early so you can immediately use maintenance throttle entering the turn and start adding power well before the apex.Turn 1 @ VIR, also turn 1 @ Road Atlanta are two examples.
I've tried both methods and in these turns my exit speed is much better setting the Vette up for early throttle.
Once in a while I'll get a "late pass" @ Road Atlanta going into turn one.
This pushes me to the inside and trail braking will get you to the apex and Thru the turn without hindering the speed of the following car you just passed.
08-12-2010, 11:09 AM
#7
Race Director
Straight line braking is taught in DE because it is safe. Trail braking where appropriate is faster.
So first thing to understand is trail braking not usefull every where in every car. What I mean by this is some corners are still better to straight line brake. Others beg for trail braking. You need to understand that first.
Second is that you cannot brake 100% and then turn. You will fly of the track into a barrier. You must give up some braking to able to carry any cornering load.
Third trail braking even done right increase the risk of spinning the car. So apporach it slow and gradual.
Fourth trail braking is very much about feel and balance. I can't teach you the mechanics of trail braking have you do it straight away. It takes feel and balance of how much braking force you can sustaing before you lose the rear end. You also need the skils to catch the rear end should you slightly over do it. Anyone that trail brakes has overdone it and gotten the back end to step out. However if you have right feel and balance you can catch it very fast before you get the car in trouble. This where fast hand and good feel come in place. It is also why people here recommed doing it slow corners. If you do lose it the car is easier to catch.
So my advice is to pick a slow corner on the track and as you brake slowly lift off and turn while still dragging the brake. Over time you will learn by feel how much brake can drag and still turn. This will then allow you brake later since you can use some distance after turn in to continue to slow down making you faster overall and faster on the straight since you can brake later than cars braking in a straight line.
Now the fun part of trail braking is that it can make you appear to be a king late braker. However you may be not braking any harder than anyone else and infact spending more time on brakes. In fact probably will need to spend a longer duration of time on brakes if you trail brake because you cannot brake at 100% and be turning. Again because you are doing it while turning you gain the advanage of using a piece of road you may previously been coasting now as part of you braking zone.
Also the hardenst braking zone on you track into the tightest corner may not be the best place to trail brake. The reason is that becuse you can't be 100% if the corner entry is too short (not much distance) and you need to srub alot of speed you many not have much distance to even try to trail brake. I know of two corners like that where trail braking is pointless. It is better straightline brake hard at 100%. Best place to do trail braking is medium braking with corners that have longish corner entry.
So first thing to understand is trail braking not usefull every where in every car. What I mean by this is some corners are still better to straight line brake. Others beg for trail braking. You need to understand that first.
Second is that you cannot brake 100% and then turn. You will fly of the track into a barrier. You must give up some braking to able to carry any cornering load.
Third trail braking even done right increase the risk of spinning the car. So apporach it slow and gradual.
Fourth trail braking is very much about feel and balance. I can't teach you the mechanics of trail braking have you do it straight away. It takes feel and balance of how much braking force you can sustaing before you lose the rear end. You also need the skils to catch the rear end should you slightly over do it. Anyone that trail brakes has overdone it and gotten the back end to step out. However if you have right feel and balance you can catch it very fast before you get the car in trouble. This where fast hand and good feel come in place. It is also why people here recommed doing it slow corners. If you do lose it the car is easier to catch.
So my advice is to pick a slow corner on the track and as you brake slowly lift off and turn while still dragging the brake. Over time you will learn by feel how much brake can drag and still turn. This will then allow you brake later since you can use some distance after turn in to continue to slow down making you faster overall and faster on the straight since you can brake later than cars braking in a straight line.
Now the fun part of trail braking is that it can make you appear to be a king late braker. However you may be not braking any harder than anyone else and infact spending more time on brakes. In fact probably will need to spend a longer duration of time on brakes if you trail brake because you cannot brake at 100% and be turning. Again because you are doing it while turning you gain the advanage of using a piece of road you may previously been coasting now as part of you braking zone.
Also the hardenst braking zone on you track into the tightest corner may not be the best place to trail brake. The reason is that becuse you can't be 100% if the corner entry is too short (not much distance) and you need to srub alot of speed you many not have much distance to even try to trail brake. I know of two corners like that where trail braking is pointless. It is better straightline brake hard at 100%. Best place to do trail braking is medium braking with corners that have longish corner entry.
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08-12-2010, 11:47 AM
#11
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The guy asked a valid question and hasn't told the people trying to answer/help him to go pound salt so let's keep the Flat Out video out of this one, shall we?
Larry, you got some good answers above. Not sure how the AWD of your turbo plays into it but all I would add is to learn it gradually on a corner that won't bite you. An example is the entry to T1 at Limerock where you have a runoff road and quite a bit of grass (when it isn't wet). I try and be threshold between 250-200 and off the brake about 1/2 way to the apex there in my car, but again, your car is much faster and heavier with AWD... i'm doing at best 125 there.
Larry, you got some good answers above. Not sure how the AWD of your turbo plays into it but all I would add is to learn it gradually on a corner that won't bite you. An example is the entry to T1 at Limerock where you have a runoff road and quite a bit of grass (when it isn't wet). I try and be threshold between 250-200 and off the brake about 1/2 way to the apex there in my car, but again, your car is much faster and heavier with AWD... i'm doing at best 125 there.
08-12-2010, 11:49 AM
#12
Mr. Excitement
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IIRC the proper quote is "Flatout...That is how I drive....Flatout"
End of the back straight at VIR begs for trail braking. That is the corner I teach it on when I have the right student. Trail Braking feels right there. Larry, If you have not done much TB and are going to VIR that is a great place to start. Your car might not lend itself well to TB. I have also found that many people start to use TB without thinking about it. As the speeds, comfort levels, vision and reaction times improve TB starts coming into play where needed.
End of the back straight at VIR begs for trail braking. That is the corner I teach it on when I have the right student. Trail Braking feels right there. Larry, If you have not done much TB and are going to VIR that is a great place to start. Your car might not lend itself well to TB. I have also found that many people start to use TB without thinking about it. As the speeds, comfort levels, vision and reaction times improve TB starts coming into play where needed.
08-12-2010, 11:49 AM
#13
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To me, trail braking is a bit like riding the brake into the first part of the turn at about 10 percent of braking capacity. And the most difficult thing is smooth transition from brake back to throttle. I suppose left foot braking and right foot throttle application eliminates distinct off/on feeling.
08-12-2010, 12:00 PM
#14
Race Director
08-12-2010, 12:06 PM
#15
Joe, thanks for that. That was really well articulated.
In your spec car, can you give me a sense of how much of the total percentage of braking you would carry into a flat, medium-speed corner? (That's obviously a contrived, general situation, but I'm wondering whether we're talking about "10% of all braking force applied" or more like 50%).
In your spec car, can you give me a sense of how much of the total percentage of braking you would carry into a flat, medium-speed corner? (That's obviously a contrived, general situation, but I'm wondering whether we're talking about "10% of all braking force applied" or more like 50%).