Forums » Grassroots Motorsports » Lets talk driving technique: Left foot braking and trail braking 1 2

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  Sept. 18, 2009 11:41 a.m. NBS2005 Dork

  In Jack Doo's 1988 book on FWD performance driving, he has two sections dealing with driving on lose surfaces, rally and ice. Doug Shepard is the expert for the rally section, the Archer brothers are the experts for the ice section.

  Shepard is a big fan of left foot braking (LFB). He is driving the turbo Dodges and talks about the advantages of keeping the engine spooled. He also comments on how it helps overall handling by balancing the car better.
  

  The Archers take a different approach. They do not use LFB and in fact comment on how they beat people who do. The are driving turbo Chevy's.

  So I'm wondering what this all means? Several ways to skin a cat? Several folks at the local rally cross LFB in their cars. But the guy who has dominated the field for years does not. Comments?

  Next up is trail braking. Sports Car did an article on this a while back and found that trail braking is faster, usually because the car travels less distance. The classic late apex approach takes more actual distance and it's enough to show in the lap times. Of course this uses LFB.
  

  I've been thinking about these things and how they relate to going faster on the track and dirt. And this is cheaper than spending $2K to net 4 whp and 4 foot/LBS of torque !

  J

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  Sept. 18, 2009 12:10 p.m. tuna55 Reader

  I can't help much, but I can say that the Lemons Amazon gets awfully light in the rear whilst trail braking. I spun it once doing that. Brake then turn afterward for that car.

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  Sept. 18, 2009 12:11 p.m. NYG95GA SuperDork

  It took some practice, but I like the LFB in autocross. Never done the rally/ice thing. I use it in conjunction with what I call the 20/80 throttle rule. Never go completely WOT, but only 80%, and never come completely off the throttle, only down to 20%. That way, there is always a certain amount of throttle on, which requires LFB. I drive a SM Neon,(FWD), and trail braking helps get rotation. Like I said, it takes practice, but seems to give good results

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  Sept. 18, 2009 2:13 p.m. alex HalfDork

  Re 80/20: why never full throttle?

  The only two things in life that make it worth livin' are guitars that tune good and firm feelin' women.

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  Sept. 18, 2009 3:44 p.m. EricM HalfDork

  In regards to LFB, I am not coordinated enough for that. In regards to 20/80 throttle, Well my throttle is a toggle switch 100/0. I ususally finsish mid pack :(

  Bad decisions make good stories

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  Sept. 18, 2009 4:05 p.m. Jensenman SuperDork

  The Abomination never responded well to trail braking or LFB, but the latter is probably more due to my clumsiness. I have a good friend who has a scary fast 300ZX turbo with (IMHO) gawdawful turbo lag, that car MUST be LFB driven.

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  Sept. 18, 2009 5:42 p.m. Appleseed Dork

  I naturally LFB. My driving instructor wigged out every time he saw me do it. I did it his way, but as soon as I got my license, back to LFB. Blame that fact that I run a Bobcat and I'm a pilot on the feeling that I should be using both feet.

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  Sept. 18, 2009 5:44 p.m. iceracer HalfDork

  I never could get where I felt comfortable with LFB. Trail braking works in some cases and not in others. The wole idea is how long to trail brake. My car gets very loose if I brake much in a corner.

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  Sept. 18, 2009 7:01 p.m. NBS2005 Dork

  So I guess it depends a lot on the car, the skill of the driver, and the course.

  For me, LFB seems to be an absolute necessity in a FWD car no matter what the venue. When I was running the Neon in rallyX, I was actually slower with LFB than without, but I have a feeling with a little more practice, it would have been different. Though I can't dismiss the Archers comments all that easily.

  As far as the track goes, trail braking just seems to make sense to me. Both of the articles I've read on the topic suggest it's harder to drive that way, takes much more concentration, and is much less forgiving of error. But when done correctly, you shorten the track significantly and that adds up to faster laps. I think of it like this, if a driver can shave 10 meters (just an example, don't know how realistic) off a 20 lap race by driving a tighter line and not using as much road, all things being equal, they'll be 10 meters in front of the other guy at race end.

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  Sept. 18, 2009 8:17 p.m. wbjones Reader

  except that sometimes that early apex and trail braking causes a slower exit speed for the following straight which can lead to being passed and not being able to dive under at the next corner even though you are early apexing and trail braking.... there being a car in the way as you try to exit... then they pull farther away on the next straight... etc....

  and I LFB at all auto-x's and even sometimes on the track, depending on the corner

  understeer: when you hit the wall with the front end,,, oversteer: when you hit the wall with the back end.... horsepower: how hard you hit that wall.... torque: how far you drag that wall

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  Sept. 18, 2009 9:49 p.m. mad_machine SuperDork

  I got LFB down when I used to run my FWD cars.. great fun in the snow.

  Unfortunately the ABS in the saab does NOT like LFB in snow and ice..

  German, Italian, Swedish, Collecting Europe one car at a time

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  Sept. 19, 2009 6:24 a.m. ddavidv SuperDork

  I taught myself LFB on gravel roads in fwd cars. It takes awhile to get the technique down, as you tend to apply too much brake when you begin learning. LFB wasn't used as much for slowing the car as it was for controlling the pivot of the ass-end. I found I could achieve some impressive car control with LFB on loose surfaces. Whether or not this made me faster I can't tell you. I was then able to apply it to autocross in my fwd cars to control understeer, but again, have no idea if it made me faster or not since I've never been a good autocrosser or have owned uncompetitive cars. (I like to blame the latter).

  Trail braking, again, is not about slowing the car as much as it is pivoting the nose in toward the apex. Your real slowing should be done before you begin turning. I've found this to be a very useful tool and believe it does make for faster corners, in most cases. This too is largely anecdotal, as I haven't had a stopwatch on me yet. That's just what I'm getting from the butt-dyno and exit speeds.

  "Having fun is my revenge on mortality"--Dustin Hoffman

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  Sept. 19, 2009 10:50 a.m. iceracer HalfDork

  In my class of ice racing, which is mostly FWD, some drivers left foot brake and are surprised when I don't and I pass them.
  How do you use the clutch to down shift if you are LFB ?

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  Sept. 19, 2009 10:52 a.m. ProjectVIN New Reader

  Just so i'm clear, correct me if I'm wrong, but LFB is used when the driver is not planning on downshifting, correct? The way I figure, LFB is good for auto-x and for rally, both of which involve accurate placing of the car inside a narrow course, and there's usually just a couple corners on a given road course where it would be useful, correct?

  I love trailbraking and see it as a necessity, especially with a FWD car. Anyway, thinking back to the concept of the 'traction circle', trailbreaking the entrance of a corner is conceptually the same as winding the power on at corner exit, its about utilizing the maximum available grip at all times, right?

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  Sept. 19, 2009 11:39 a.m. procainestart Dork

  Can't remember where I read it, but for Solo2, there have been national champions who do and don't LFB. M. Schumacher left foot brakes (search my old posts for a link to a PDF article about it). As mentioned, it takes practice. After a bunch of 7-8 years of doing it, I can brake equally well left or right and predominantly LFB on the street.

  As for shifting, I don't know if this would fly while racing, but on the street I blip the throttle to get the revs right and the shifter goes in. Takes some practice (transmission won't be happy if you keep messing up) but is satisfying once you get it.

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  Sept. 19, 2009 12:36 p.m. ProjectVIN New Reader

  I figured all, or most F1 drivers LFB because of the lack of a clutch pedal and the lack of space in the footwell.

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  Sept. 19, 2009 1:16 p.m. griffin729 Reader

  ProjectVIN wrote: I figured all, or most F1 drivers LFB because of the lack of a clutch pedal and the lack of space in the footwell.

  Don't forget pretty much all open wheelers started in karts in kindergarten. LFB that long and it's kinda natural.

  From the movie Remo Willians:(said to his master) Remo: Somtimes, you are a real pain in the ass.Master Chiun: That is because it is the shortest path to your brain.

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  Sept. 19, 2009 2:10 p.m. Per Schroeder Technical Editor/Advertising Director

  The trick is to become ambifooterous and have the room to do it. Longer courses (rally, road course) I'll switch back and forth depending on the situation. If it's an autocross course, the move to LFB is done right after the 1-2 shift.
  

  I just moved the clutch pedal on my LeGrand over 1.5" to make it easier to get my left foot on the brake pedal. After driving Joe's LeGrand, it became obvious that's something I'll have to do on mine.

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  Sept. 19, 2009 2:13 p.m. Tommy Suddard SonDork

  griffin729 wrote:

  ProjectVIN wrote: I figured all, or most F1 drivers LFB because of the lack of a clutch pedal and the lack of space in the footwell.

  Don't forget pretty much all open wheelers started in karts in kindergarten. LFB that long and it's kinda natural.

  That's where I picked it up.

  'cause we're aliens, and thats how we roll.

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  Sept. 19, 2009 4:12 p.m. Varkwso Reader

  LFB to keep the revs up (Oak Tree at VIR and T7 at Road Atlanta 2 examples). Trail brake to rotate a 3200 pound V8 Amercan car...

  Both keep the car higher in RPM when the stars align...

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  Sept. 19, 2009 7:36 p.m. JG Pasterjak Production/Art Director

  Left foot braking for me has always been car, course and condition dependent. Back when I was running the Miata I used to left foot it all the time. The Corvette, however, never seemed to like it. The MS3, while you'd think would like that left foot on the brake so you can keep the turbo going, doesn't seem to be a fan of left footing, either. Of course, in the hands of someone else it may completely lend itself to left foot braking.

  I guess what I'm saying is that you have to experiment. My guess is that once you become proficient you will find situations where you are faster using the left foot, and situations where you are faster doing a traditional right foot transition.

  jg

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  Sept. 19, 2009 8:06 p.m. wbjones Reader

  Varkwso wrote: LFB to keep the revs up (Oak Tree at VIR and T7 at Road Atlanta 2 examples). Trail brake to rotate a 3200 pound V8 Amercan car... Both keep the car higher in RPM when the stars align...

  haven't run Atlanta yet but at VIR not only do I LFB for Oak Tree but the gearing works w/ my CRX so that I can LFB for 3 & 4, and after I downshift for the Roller-coaster I stay in 3rd until I exit HogPen so any braking on the down hill esses is done LF

  when I first switched to LFB ( I learned on automatics) I found I was braking way to early for corners... the time difference between having to move my right foot from gas to brake and back to gas..

  understeer: when you hit the wall with the front end,,, oversteer: when you hit the wall with the back end.... horsepower: how hard you hit that wall.... torque: how far you drag that wall

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  Sept. 19, 2009 9:43 p.m. Rad_Capz New Reader

  In reply to Tommy Suddard:

  Good observation Tommy. I started in 1/4 midgets when I was about 9-10. Never really thought about why always I left footed till you mentioned that.

  John Paige

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  Sept. 19, 2009 10:28 p.m. ProjectVIN New Reader

  Per Schroeder wrote: The trick is to become ambifooterous

  Walter Röhrl = Ambifooterous.

  http://www.youtube.com/watch?v=yyVHj3sHVHQ

  
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  Sept. 20, 2009 9:34 a.m. White_and_Nerdy New Reader

  For me it depends on the circumstances. FWD or AWD, I'll LFB, particularly on an autocross or rallycross course. But in my Miata, I've only used LFB for faster throttle/brake transition times, not to rotate or balance the car. I think the Miata is wonderfully balanced as-is, and I don't feel the need to LFB to make the car handle the way I want. I'm not sure about LFB in RWD on a slippery surface - haven't tried it yet.

  Schumacher got his start in karts, which force you to LFB. He was an LFB expert when he was younger than when many of us drove for the first time. :) So I'm not surprised that he does it, regardless of F1 cockpit setup.

  Trail braking, again, it depends on the car. I'm also more likely to do it in a nose heavy car (FWD, AWD) to get some rotation than a well balanced RWD car.

  - Justin

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