27 replies to this topic

[Sean L]

I heard Brundle mention during commentary during one of the races this year that Michael is the only driver who doesn't use left foot braking ie. he brakes and accelerates with his right foot - heel & toe.

Is Brundle correct?
I though that the minority of drivers used lfb since it was difficult to master.

Am I correct in thinking that this technique originated from rally drivers?
I heard that Berger was one of the first to use it in F1. Does it actually provide significant advantage in F1? If it does, then how come Schummie is so fast withput it...

[IndyIan]

Sean L.
Did martin brundle actually say micheal heel and toes in his f1 car? Is that for downshifting? I thought the semi auto trans pretty much matched revs for the drivers.
I've heard the biggest advantage to using both feet is that there is no "lag" time between getting off the throttle and onto the brakes at the end of the straight and that it is possible to "pre-heat" the brakes by applying them lightly and the end of the straight with the throttle on.

I believe the technique originated from rallying, there they use it to get the back end to hang out in corners. I've tried it and it works very well on slippery surfaces even in a 85 corolla, very fun!

[Limey]

Left foot braking in rallying started in the 60's with the FWD minis. I think it helped by pushing the front of the car down to compensate for the lift on acceleration out of the corner as well as save time. In F1 in the turbo days, it helped keep boost up.

[Sean L]

IndyIan, I can't be 100% sure that Brundle mentioned "heel & Toe-ing" specifically but he did say that MS had a problem controlling the throttle with his heel after his accident. (If you remember he had a deep gash on his heel from where the suspension components pierced the drivers 'safety cell')

I don't think he uses 'h & t' for downshifting because as far as I know the semi-auto 'box blips the throttle automatically like a double-d-clutch (on the Ferraris) on the down changes.

I agree that the main advantage in LFB is to preheat the brakes but it doesn't really have a car contol or performance advantage since MS probably uses his toe for that. IF he does in fact 'heel & toe'. If he doesn't then his footwork must be incredibly quick and smooth.

I've tried it myself a few times in my Golf (on dirt roads) but I find that the feel is totally out in my left foot which makes me brake far too hard without meaning to. Probably takes some getting used to. MS obviously drives quite well whatever the technique he uses - it's probably the way he's always driven going up in his karts.

[silver]

Mika Hakkinen was the first of the F1 drivers to switch to two pedals. That happened in the beginning of the -94 season. The tested the car during winter tests with two pedals only.

Hakkinen used 3 pedals in the early part of the -97 only getting his ass kicked by DC. He switched back to 2 pedals in Silverstone and was faster that DC from that on.

Some drivers use nowadays left foot for breaking some others dont.

------------------
Only two things are infinite; universe and human stupidity; and I am not sure about the former
-Albert Einstein-

[IndyIan]

Sean L,
I find that to use LFB properly you need to going fast enough in the corner to be pretty much on the limit of adhesion and then a moderate touch on the brake pedal will send the back end out. When you want to quit sliding let off the brake and stand on the gas, this "pulls" the back end in line with the front. Snow covered empty parking lots are good places to learn too, no ditches!

Some cars are better at it than others, my old 85 corolla seemed to love it but my 91 Escort GT with wider tires and stiffer suspension isn't as willing, I have a feeling your golf has more in common with an escort GT than a corolla so it might not feel very natural.

[Sean L]

Silver,
Thanks for the info on MH.
You said "Some drivers use nowadays left foot for breaking some others dont."
Do you know this for a fact. I also thought so and was surprised to hear Brundle say that MS was the only one not LF Braking. I assume MB knows what he is talking about since he's in the paddock with the drivers a lot of the time.

IndyIan,
The Golf's on the limit handling on moderately slippery surfaces (sand) is almost on the verge of snap oversteer. I have a feeling that if I touched the brakes at all I'd be off the road like a frisbee.

The last time it snowed in this area (Johannesburg - South Africa) I was only 10 years old. I would dearly love to find out what driving in the snow is all about but I'll just have to settle for dust roads and dried out marshes, which are quite good as there are no ditches.

Is your 85 Corolla RWD? I can't remember when Toyota switched to FWD. RWD is much more fun and easier to 'play' with the back.

[silver]

These use left foot breaking for sure:

Hakkinen,Villeneuve,Wurz,RSchumacher

These at least tried it out:
Barrichello, HHF

I would think they use right foot for breaking

DC, MSchumacher, Mika Salo


Mark Blundell said during 1995 season that he tried Mikas technic aswell but found it impossible. Mika threw the car into the corners by using LFB. Maybe one reason for that was that the 1995 McLaren handled like a dog.

[PDA]

Origins - I believe that the origins of LFB was with front wheel drive rally cars of the late fifties and early sixties. It was introduced by Scandinavians, the best known probably being Makkinen (father of three times world champ Timo) and Aaltonen (sp?) who were works mini drivers in the mid sixties. I am sure it was used earlier by Saab 96 drivers such as Carlsson. It could be used in two ways. The most spectacular was to throw the car at th corner, the car understeers like crazy, kick the brake pedal to lock the back wheels and induce instant oversteer. Keep power on to the front to prevent them locking. the second way was used in very slippery conditions such as snow and ice, where applying brake and accelerator together would prevent the front wheels from locking, either while slowing for the entrance to a corner, or when accelerating away from a corner. this latter technique is now used in traction control systems. I foind that with the latter technique, I could perform much better in slippery conditions in my Saab 96 which would be totally outclassed in dry conditions by the prevelant rear drive Ford Escorts.

LFB in formula cars is quite different and arises from the compulsary use of LFB in Karts. If you are used to it, you can brake just that little bit later into a corner, and get back on the power sooner and more smoothlyand over a lap that adds up to measureable time. As most of the drivers now come from a karting background, they continue to use the technique when they start in F3, F3000 and then F1. It seems it is very difficult for a RFB to change from one to the other, which is hardly surprising. Barichello said that his poor results in the beginning of the 94 season were partly due to him trying LFB for the first time in an F1 car. It was also reported that Damon Hill attempted to use LFB at the beginning of the 98 season, couldn't get it to work, and reverted to RFB for th second half of the season. Jordon won a race (Spa) and gained points in every race thereafter.

I have read in many places that M Schumacher uses LFB, so I am surprised to hear Brundle saying that he doesn't.

[Jonathan]

PDA

You drive a SAAB 96 ?

I loved those cars !!!

Unfortunatly do to a a lack of self-adjusting rear drum brakes, I never really got any good at left foot braking. I became something of a "Hand-brake" turn expert.

Now that I drive an all-wheel-drive Subaru with Anti-lock brakes, I havent a clue what to do !

[PDA]

J - I drove a Saab 96. That was a long time ago. I must admit to using the handbrake to swing the rear much more than using LFB. But then, I was definitely not Timo Makinen.

I also has a Subaru Legacy GT wagon a couple of years ago. Difficult to make it do anything out of the ordinary, but the AWD gave great traction on snow.

[IndyIan]

Sean L.
My Corolla was fwd but I think there were versions a bit older that were rwd.
In Canada there are almost no rwd cars left, the only resonably priced ones are mustangs, cameros, and I think nissans 240 SX. I think this is because of the snow, watching a mustang trying to get around in any amount of snow is quite funny.

I would love to try driving on a dryed up marsh (I assume they almost like salt flats)
It would be great fun to set up a course and race around. Have you ever tried solo racing? One of the best i've been to was in a sandy dusty parking lot, it evened the cars up and i actually beat some Civic CRX Si's. Some of the guys weren't too happy being beat by a car worth less than their wheels and racing tires.

Does anyone know about LFB in rwd cars? I know in 4 wheeler racing they use the fron brake to hang out the back end sometimes. I wonder if it works with cars?

[PDA]

LFB in RWD cars would not help kick out the rear. I think that it is used in formula cars to reduce time between off throttle to on brake, and the converse, not for changing the attitude of the car, as it is with FWD on gravel.

[DangerMouse]

I think Michael uses left foot braking where he feels it is appropriate, he uses it mainly to moderate wheelspin out of bends (as does HHF MikaH and in the last two seasons Hill)
Although Mika H is a full on left foot braker.

Herbert doesn't use it as his left ankle is a solid lump of bone and it doesn't actually move at all!

I honestly don't think it makes a great deal of difference a driver will go quickest with whatever he feels comfortable with.

[Sean L]

PDA,

"There are still quite a few RWD old Fords, BMW's, Toyota's, Chevs and Alfas around here ( they keep old cars going here for ages) but as far as new cars go mainly just BMW. Otherwise only imported sports cars are RWD."

I was specifically refering to RWD cars that are commonly found here in South Africa.

You are right though, but we don't have too many American sports cars here (I think there are less than 10 imported Vipers but quite a few Corvettes). I would class all of those that you mentioned as imported sports cars.

Sean



[This message has been edited by Sean L (edited 11-19-1999).]

[PDA]

Sean - don;t forget Corvette, Viper, Mustang, Camaro/Firebird plus all of the truck based SUVs.

[Don Capps]

Actually lfb was originated in track racing by the Chaparral team back in 1964 when they starting using their "automatic" transmission in the USRRC. It first became public at the Laguna Seca USRRC event in May of that year.

Jim Hall, Hap Sharp, Roger Penske, and Phil Hill all used lfb when driver the Chaparral 2's in their various guises. It allowed the driver to go deeper into the turns and accelerate faster out of them when compared to the traditional method.

BTW, at one point Hall also used a set up that dialed all the dive out of the Chaparral while breaking, but dropped it since it seemed to deaded some of the feedback from the front end of the car.

------------------
Yr fthfl & hmbl srvnt,

Don Capps

[f li]

LOL! At last - I caught DC with a proofreading error!

If they dialed out the dive under breaking it would be useful at most once per race! :^P
J. Hall could have used it at Las Vegas!

DC, no offense meant!

[Yelnats]

Yeah, Don. Jim Hall/Hal Sharp and the Turbo-Hydromatic 2 speed Chapparal was the first instance of left foot braking that I heard of at the time. I understand it developed because they had learned left foot braking when driving automatic road cars and it seemed only natural to transfer this to the racing circuit as the left foot had nothing else to do!

[tak]

Left Foot Braking, like anything else driving related, just takes practice. It is one of the few racing skills that can be safely practiced on the street.

The principle advantage of lfb is to shorten the time getting from one pedal to the other. It allows the driver to be on the gas a fraction longer, and then get back on the gas faster and smoother. A side benefit is that it also reduces the cars "set" time.

Also keep in mind that one doesn't have to use exclusively the left OR right foot. For example, I use left foot braking when I don't have to shift (e.g. Laguna turns 3, 6, and 10), and right foot braking when I have to shift. Also, gently dragging the brakes while entering high speed corners seems to settle the car (e.g. Sears Point turn 10). I think it transfers a little weight to the front without upsetting the balance like lifting would. Anyway, that's my experience from a solid axle rwd Rx-7...

[regenmeister]

I´m quite sure MS uses LFB.
I base this upon that RB is used to RFB when he drove in Stewart but in the Ferrari it´s impossible to RFB since there isnt anywhere to put your foot else then on brake pedal, so he had to learn to LFB during his first day. So i´ve read.

[Sash]

MS definately LFB's. I read an account of him in his early F1 days of going through a long sweeper and using some brake and throttle to settle the car. The thing Martin Brundle was talking about is the fact that MS does normal braking (at the end of straights, etc) with his right foot. He uses left for settling the car, and right for maximum feel.

Must be all those days he spent when he was young karting in the rain by himself....

[smarty]

Reading all posts in this thread, I'm totally confused about who uses which techniques, LFB or RFB?

Why did Rubens abandoned LFB after he practiced LFB in 1994? Was he unsuccessful at the end or is it a wrong info?

[westendorf]

LOL, I just caught fli in a spelling error, as well as others, if one is slowing a car one applies the brake, not the break as in smashed or broken. I know I'll regret this one as my spelling can such, I meen suck from tyme too time. I may buy an automatic tranny car just so I can get better feel in my left foot for kart racing. Short track stock car racers all use left foot braking, it does as many have said here already help to reduce the lag time, but also the chassis seems to take a set in the cornors better when the throttle is on. Trail braking is a mixed blessing because of the friction circle. Good to see Don Capps name back.

[davo]

The friction/traction circle is something which all drivers intuitively pick up on the acceleraton side of the apex of the corner. That is that as the corner is opening up (increasing the radius of the turn) then more and more throttle can be applied. They don't drive cornering at the limit of traction and then transition to straight ahead, and THEN apply throttle. They blend the two actions and so have the benefit of simulataneously getting greater than 50% of the grip in each direction. (If you like 0.7 + 0.7 > 1 )

When it comes to the braking side of the corner the physics works just as well even if the drivers often don't ( I include myself in this catagory)

Picking up an older part of the thread 4WD subarus do tend to have handling of understeer or more understeer but can be made to oversteer

Approaching a corner at moderate speed, down change, no throttle and turn in. The engine braking will unstick the rear and any throttle while OS will keep it OS. I have done my silliness on large, flat, open, private, dirt patches in 1st and 2nd.

I presume this is how the WRC drivers initiate their spectacular donuts at rally ends. I have neither the budget or the stupidity to test that theory on tar.

[westendorf]

Davo, I do believe the explaination of the friction circle is actually that any tyre can only supply 100% traction in any one direction or combination of directions at any given time. If you are using 100% of the traction to brake then you have no residual traction to turn left of right, as when you have locked up all 4. If you are using all available traction for cornoring then you have none left for acceleration, and so forth. It's kind of like post game athletes saying how hard their team played and gave 110%, it's not possible.
ciao.

[davo]

Westendorf,

You are quite right 100% is by its very definition all of something. However when racing tyre is at 50% of its ultimate cornering traction it can contribute MORE than 50% of accelerative or braking thrust (and of course at many other combinations) it is a friction circle after all not a friction diamond.

The 100% of available tractive work at (maximised) part loadings in both directions is greater than the sum of work with 1/2 the time at 100% in each of the directions. This is not an attempt at the trite 110% effort comment of various sports people.

The fastest way will be to "ride the circle", where as braking in a straight line and then cornering will always be slow.

Happy to try other explanations although Carrol Smith "Drive to Win" and the Millikens with "Race Car Vehicle Dynamics" do a better job than me.

More than happy to let you believe whatever you want. The facts live quite independent of what either of us actually believe after all.

Cheers,



[This message has been edited by davo (edited 01-19-2000).]

[MrAerodynamicist]

Except it's not a friction circle anymore, aerodynamic forces have reshaped it to the Friction Oval, IIRC

------------------
MrA
All hail King Jaxs