mrbill_fl

I've been reading some articles on threshold braking, and this is different than what I was taught by skippy, and also different than how I drive.

on a scale of 1 to 10, 10 being lockup, I brake about a 2 peddle, to settle car, and get all calipers touching. then move to 4-5-6-7-8-9, and release the brake just before the turn in.... (later if trail braking).

the braking backwards technique (as I understand it), is more like 5-6,7,8,9,9,8,7,6,5,5,4 turn-in. braking harder initially, and scrubing lots of speed initially, then easing off the brake. (what I would call 'coasting').

is this how you brake? is this how I shoud teach?


If its a better teaching technique, fine, but it seems slower, and would encourage early downshift, and transmission braking... thus increasing chances for spins under braking by letting out clutch too soon. (transmission braking is at the top of my "'bad habits to break" list for students.)


so, whats the deal with backwards braking? is this how you teach?

Jean

mrbillfll

It seems that you are only asking the question for teaching, and not how to go fastest during a race for instance?
Thanks

hacker-pschorr

This sounds more like what Duck Waddle taught us at the PCA DE Memorial Weekend (He is a skippy instructor). This is how I try to drive on the track.

Bob Rouleau

Mrbill - teaching a braking technique varies with the skill level of the student. Beginners are taught to go easy on the brake pedal at first then build up the braking force followed by a "fade" off period to avoid uncontrolled weight transfer to the rear of the car as would be caused by an abrupt release of the brake pedal. Trail braking is not taught (in my school anyway) until the driver can "fade off" the brakes properly and consistently.

Advanced drivers are still taught to transfer weight initially - to get a wider contact patch then brake harder. Fading off is always taught.

So, a beginner might be taught 2--3-4-5-6-7-8-9-6-4-2-0.

An advanced driver would go something like 2-5-7-9-6-3-2-0.

One exception to this is when a driver struggles to determine to correct entry speed to a fast corner. Most over-brake. The standard technique is to teach them to brake earlier but not as hard, in othter words the rate of decel is less, but the duration is longer. This allows the brain more time to judge the entry speed and avoids the customary over-braking for fast corners.

Best,

Phokaioglaukos

The SB trailbraking way, as I recall it from Monday's instruction, is to brake firmly and then ease off the pedal and on to the throttle so that the brake/throttle transition is imperceptible. Snapping off the throttle is the big "no no" that they are counselling against. One of my instructors suggested resting my heel on the floor and braking with the toes for more feel. In the car control clinic we are just in one gear, so I did not try that and also heel and toe. That might be an issue for me, but something to try.

swftiii

This is what I have been tought over the years - not to all of a sudden release the brakes, but to ease off them. I also remember seeing a special comparing M Schumacher to other F1 drivers in the braking zone and MS started his breaking earlier than others, but tended to have a faster corner/apex speed. I attributed this to the fact that he is braking more like the above and can better judge his entry speed.

Just my opinion.

-Skip

Larry Herman

I think that to answer your question properly we need to define the parameters under which this "heavy braking" occurs. Threshold braking is one of the last places to find more speed, and it usually occurs in a long braking zone where you need to reduce triple digit speeds by at least 50 mph. Under this situation, you have the time for the car to set, generate maximum braking for a few seconds, and then ease back off the brakes as you turn in.

Again, by our definition the turn we are approaching with such a dramatic reduction in speed will necessarily be a slow one, and therefore will be driven quicker with trail-braking. The stiffness of your suspension and the grip of your tires will determine how quickly you can build the braking effect. In my car it would go 2-5-8-9-9-9-7*5-3-1. At the *, I am starting my turn-in, and have maximum steering input by the time I release the brakes (1). An average student in the average car would be much closer to what Bob R wrote.

TheOtherEric

I generally agree with Bob. I was thinking that advanced trail-braking drivers are more like:
2-7-9-9-9-9-7-5-3-turn-2-1-0-gas.

But I instruct my students like Bob suggests.

It's easier to control your corner entry speed when you're not decelerating dramatically. So "4-5-6-7-8-9-turn" (from the original poster) would make it hard to keep consistent corner entry speeds.

M758

I have never used the number system described above, but teach and drive the follwing way.

I tell my stundents to give the brakes a rapid firm pressure, but it should not feel harsh. That means it should not be a drive then "slam on the brakes for all you are worth", but more of a drive then get on the brakes frimly and strongly, but without slaming.

My idea behind this is that "slam" can cause the brakes to lock well before the weight gets transfered to the nose. Thus you a static weight on the nose to less then full brake force.

If you push the brakes on really gently like it can be just as bad since the car never loads the nose so you have limited braking.

The slow yet firm application of brakes allows the car to load the nose an then take full use of that. As you slow you use less brake and I personally try to slowly trail off the brake just after turn in so there is no noticeable point of brake release.

Most of my speed reduction occurs in that point just after brake application when you can feel the front end loaded up. Once the nose dive effect is reduced I also reduce the brake force as if I do not it wil lock up.

So I guess number wise it would be more like 7-10-10-9-9-8-7-6-5-4-3-2-1.

Turn in varies greatly, but ranges from 9 or 8 down to 1 to as little as when I get to 2.

My foot does sort of a touch the pedal and push a little then squeeze really hard.

mrbill_fl

ok, judging from initial response, braking backwards IS a teaching technique.

during my 3 days skip barber RACE school, (1995), they taught brake hardest just before the turn-in.

They showed a slow motion video of a formula car, threshold braking. the wheel would stop then turn, about 6 times a rotation, like a second hand, tick tick tick. the wheel would move then stop, showing the 'optional' threshold technique.

I have seen this myself watching Spec Racers' at several national races. (flagging), the wheels would look like they locked, 3-6 times, just before the turn in...(over 3 car lenghts), These were national front running drivers, so I figures they were doing it right.

I guess I'm ok with this philosophy in HPDE, but it seems slower to me.

fwiw, I find the typical bad habit is to over brake (early), then coast (easing off brake), to the turn-in... but the overbrake is really only a 6 peddle, way too early....

to fix this bad habit, I have the student 'wait' to brake later and deeper, which forces them to use more brakes (I want to feel the abs,..... then brake almost as hard, were I dont feel the abs)



*I guess we all need to teach the same things/way, But I'm still not conviced this is a better way to teach or drive.

braking backwards IS the PCA policy? Y/N?

(thanks)

mrbill_fl

Oh, the number scale tip was from terry earwood, (skippy).

I like it to quantify brake pressure.... I also talk about 'curling the toes', to change the pressure...

its too hard to modulate the tricept, so I really use the ankle to change pressure, the curl toes seems to help students find a different muscle group


------------
LH: I'm not looking to teach speed with Threshold braking, more the saftey and building of confidence that comes with knowing you can stop the car in a short distance.

So many guys I teach have big HP cars, but they are not ready to go fast yet... (and they want fast!) but once I feel they can stop the car, I'm more likely to allow them to go a little faster. SO I stress threshold braking, right after line and flags.

Larry Herman

I don't think that "braking backwards" is exactly what we are doing, but it is a good way to distinguish that method from the "jump off the brakes and turn in" method. Done and explained the way I do it (YMMV), it is more akin to squeezing on the brakes, generating maximum braking effect, and then unsqueezing them as you begin to turn-in.

M758

There is no "policy", but teach my students the opposite of what you do.

My students tend to either brake very early in too soft a way thus never loading the front.

OR

Simply try to out brake themselves thinging "Porsche" brakes will save the day. Thes folks slam on the brakes way to late.

Depend on what kind of student I will stress different things, but I trully believe that you need to do most of you braking just after brake application. Get on them hard early while you can used the weight transfer to load the fronts. One way to lock up the brakes is to brake gentle at first, then try to push really really hard. At first your gentle slowing never puts much weigth on the nose. Then as you push harder you can easily exceed the tires friction level with that of the brake rotors causing lock up.

Seems to me the reason sper racers lock up the brakes at turn in is that is where the are trying to exend the brake zone. If you did not have to worry about lock up then you just push as hard as you need to for the entire brake zone. However one you start to reduce how much you slow down by the weight transfer on the nose is reduced this reducing you total braking capability. It is in this zone the driver must really modulate the brakes as each foot travels he need to let off a little. Doing to so much can cause a missed apex to require you to brake sooner.

Really braking just right is one of the hardest thingst to do in race car.

For the novice student I see to have them learn how to rapidly depress the brakes so that they can get the shortest stopping distances while maintain control on the track.

My general feel is that once you get on the brakes you can't push them any harder and get cause the car to slow down any more. You simply don't have the advantage of weight transfer to help you.

Of course if you slam on the brakes too fast before the weight transfer occurs you lock up which has is own problems.

That said braking technique and knowing when and how much to brake for any corner are different things.

Phokaioglaukos

This merits repeating, I think. In a slow turn one can rotate the car quicker by turning in while on the brakes. Look at the asterisk in Larry's explanation.

As always, brake firmly without jabbing the pedal so that weight transfers to the front wheels (broadening the contact patch and loading the suspension)--this sets you up for maximum braking and is the right way to brake in any turn. For a slow turn, turn in while still on the brakes and ease off the brakes as the car rotates (you should feel the rear coming around), transition to throttle as the car nears the apex and then full throttle out of the turn. Feel for the balance of the car as you transition smoothly to the throttle. Snapping off the brakes will transfer weight too quickly to the rear and often lead to a spin. For any braking gentle release is desired, even if done quickly!

Fast turns are not for for trail-braking.

mein51

This reminds me of my first track experience. My instructor told me to think of my gas and brake like my ***** - one for gas one for brake. You don't want to squeeze them both as tightly or as quickly as you can, but rather "ease" into it. You also wouldn't want to squeeze them both as hard as you can - ease on and ease off. You can squeeze them simultaneously, but only so much for each.
I know, its a bit vulgar... but I've always remembered it!