Re: left foot braking: what is that?

"Michael Gaudette" <[email hidden]> wrote in message news:[email hidden]... > What is left foot braking? (yeah yeah, I know, it's using your left > foot to press on the brake) LFB helps to get smoothly from the gas to the brake and back on the gas. > But I can't see how this is helping at all? (did I mention I didn't > know much about racing cars?) And why do you guys make it look so > dangerous? Nah, not dangerous at all. Those who see the light just went ahead and did it, without further discussion or comment. Those who have trouble chewing gum and typing, well, just thought it all to death instead of jumping in. FWIW, I had CH pedals when I first got GPL. If you own a pair, or just saw them in a store, you would intuit that the only comfortable way to use them is to keep both feet on there all the time. The CH pedals were designed and sold as sim airplane rudder pedals, where you normally keep both feet on the pedals (no temporal problems in FS98, right Eldred?). Even without splitting the pedal axis, so the gas and brake work independently, you gain quite a bit in smoothness coming off the gas and getting on the brake. Harsh transitions really upset the car, and contributes to lockups when you otherwise wouldn't. This is especially important where the braking zone starts in a curve, as you find at Watkins for example. Roll off the gas smoothly as you roll on the brake. Getting off the brake smoothly at apex is important, too, maybe even more so. It should have a definite rolling feel as you ease off the brake while turning in, and squeezing in enough gas to keep the rears under you at apex. None of this will make much sense until you get used to "feel" of a GPL car, and find a setup that works well enough for you to notice such things. And by then, you'll have a good enough understanding to know what's right for you. Miagi-san summed it up best, I think. "LFB do; LFB don't do. But no LFB do some. Middle of the road get splat!" Or something like that... > I can only see one result of LFB: quickly used up brake pads.... > You guys want to fill me in? That's in the other driving course. Octagenarians in our southernmost penisular state typically rest their left foot on the brake as they cruise down the highway. Hopefully, you'll be paying attention, and put the brakes on only when you want them on, as a conscious act. Michael.

Hi all! Allright, I am continuing my "newbie" line of questions (until I get GLP from Daxe that is ;-) with this one: What is left foot braking? (yeah yeah, I know, it's using your left foot to press on the brake) But I can't see how this is helping at all? (did I mention I didn't know much about racing cars?) And why do you guys make it look so dangerous? I can only see one result of LFB: quickly used up brake pads.... You guys want to fill me in? Michael

In article <[email hidden]>, "Michael Young" <[email hidden]> writes:

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>> But I can't see how this is helping at all? (did I mention I didn't >> know much about racing cars?) And why do you guys make it look so >> dangerous? > >Nah, not dangerous at all. Those who see the light just went ahead and did >it, without further discussion or comment. Those who have trouble chewing >gum and typing, well, just thought it all to death instead of jumping in. >FWIW, I had CH pedals when I first got GPL. If you own a pair, or just saw >them in a store, you would intuit that the only comfortable way to use them >is to keep both feet on there all the time. The CH pedals were designed and >sold as sim airplane rudder pedals, where you normally keep both feet on the >pedals (no temporal problems in FS98, right Eldred?).

Actually, I haven't played FS98 yet. I have the CD, but I never loaded it... So...I don't know HOW easy rudder pedals would be. Besides, I have a TSW2mod...<g> Eldred -- Tiger Stadium R.I.P. 1912-1999 Homepage - http://www.umich.edu/~epickett GPL hcp. +52.52 Never argue with an idiot. He brings you down to his level, then beats you with experience... Remove SPAM-OFF to reply.

True, didn't understand the dynamics. Bloody hard tho' with my road car's box... I can now pretty much get it up and down the gears, but not in traffic. Basically just playing with the approx. revs until it slots in. I'm going to get you to demo your skillz someday. Jan. =--- m.seery wrote...

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> Hehe Jan. > > You know about these techniques but I remember giving > you a lesson on clutchless changes ;-) > > I knew I'd get revenge for the motorhome post <G> > > MS

Cheers mate. Just binned a similar reply. ;-) Jan. =--- m.seery wrote... > You are confusing trailbraking with heel and toeing. > <snip>

True... I forgot. Jan. =--- ymenard wrote... > <snip> > Another reason you didn't mention<snip> >

#The main advantage is better control over the weight shifts in your vehicle, #by balancing throttle agains brake while trailbraking into a corner. It's #danger lies in overdoing it, i.e. taking too much load off the rear of the #car, thus making it come around on you. Hi there. When you said trailbraking do you mean you press on the gas while braking with the SAME foot? I've seen that on those Japanese vcds stock car racing. Do they do that in F1 too?? thanks. --- shellfer.

That's a fairly difficult question to answer seeing as you seem to lack the entire background as to why LFB is benificial. The main advantage is better control over the weight shifts in your vehicle, by balancing throttle agains brake while trailbraking into a corner. It's danger lies in overdoing it, i.e. taking too much load off the rear of the car, thus making it come around on you. But, I've probably lost you by now.... time to call in the pro's. I suggest you aquire and read "Drive to Win" by Carroll Smith. He's real good at explaining this kind of stuff (and other related topics such as slip angle and traction circle too). -Yes, that's right, to get good at GPL without natural talent and/or a racing background you need to turn to real-life literature. That said, I'm personally still unable to do it and I get around the tracks in GPL in an non-embarassing fashion (if I may say so myself ;-)), using right foot braking (I do trailbrake in some corners, though). Jan. =--- Michael Gaudette wrote... > Hi all! > <snip>

"Jan Verschueren" <[email hidden]> wrote > That's a fairly difficult question to answer seeing as you seem to lackthe > entire background as to why LFB is benificial. Another reason you didn't mention is simply that when you are left-foot braking, you gain a couple of milliseconds by not taking your foot off the gas onto the brake pedal. It may not be big, but each couple of hundreds of a second makes for a lot at the end of each lap. You keep both feet on both pedals, so your reaction is faster. -- -- Fran�ois M�nard <ymenard> -- May the Downforce be with you... -- http://www.WeRace.net -- People think it must be fun to be a super genius, but they don't realise how hard it is to put up with all the idiots in the world.

Juan Montoya uses right-foot braking, so it's good enough for me :) Marc. "Jan Verschueren" <[email hidden]> wrote in message news:[email hidden]... > That's a fairly difficult question to answer seeing as you seem to lackthe > entire background as to why LFB is benificial. > > The main advantage is better control over the weight shifts in yourvehicle, > by balancing throttle agains brake while trailbraking into a corner. It's > danger lies in overdoing it, i.e. taking too much load off the rear of the > car, thus making it come around on you. > > But, I've probably lost you by now.... time to call in the pro's. Isuggest

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> you aquire and read "Drive to Win" by Carroll Smith. He's real good at > explaining this kind of stuff (and other related topics such as slip angle > and traction circle too). -Yes, that's right, to get good at GPL without > natural talent and/or a racing background you need to turn to real-life > literature. > > That said, I'm personally still unable to do it and I get around the

tracks

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> in GPL in an non-embarassing fashion (if I may say so myself ;-)), using > right foot braking (I do trailbrake in some corners, though). > > Jan. > =--- > Michael Gaudette wrote... > > Hi all! > > <snip> > >

You are confusing trailbraking with heel and toeing. Trailbraking involves braking slightly later and entering the turn still on the brakes whilst balancing the car with the gas. (Literally, trailing off the brakes in the corner) Heel and toeing is used to match the engine revs to roadspeed on downchanges. Whilst braking, the throttle is blipped to raise engine revs to match the lower gear during the change. MS > Hi there. When you said trailbraking do you mean you press on the gaswhile > braking with the SAME foot? I've seen that on those Japanese vcds stockcar

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> racing. Do they do that in F1 too?? > > > thanks. > > --- > shellfer. > >

Hehe Jan. You know about these techniques but I remember giving you a lesson on clutchless changes ;-) I knew I'd get revenge for the motorhome post <G> MS "Jan Verschueren" <[email hidden]> wrote in message news:[email hidden]...

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> Cheers mate. Just binned a similar reply. ;-) > > Jan. > =--- > m.seery wrote... > > You are confusing trailbraking with heel and toeing. > > <snip> > >

IIRC there was an 'optimal' revs that stopped clutchless changing from screwing your Gearbox, something around the 5600 revs mark in my old Vauxhall. I gave up messing with stuff like RL LFB'ing and clutchless changing when I realised I was being serious danger to others and myself ;) Alan. Jan Verschueren wrote:

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> True, didn't understand the dynamics. > > Bloody hard tho' with my road car's box... I can now pretty much get it up > and down the gears, but not in traffic. Basically just playing with the > approx. revs until it slots in. > > I'm going to get you to demo your skillz someday. > > Jan. > =--- > m.seery wrote... > > Hehe Jan. > > > > You know about these techniques but I remember giving > > you a lesson on clutchless changes ;-) > > > > I knew I'd get revenge for the motorhome post <G> > > > > MS

Don't think I've actually revved my road car (Nissan Almera) to 5600 yet. Although indications are it's more of a revvy than a torque-y car. ;-) I don't even try any of that stuff in traffic, but when I have the road to myself I do experiment. I always double declutch and blip on uphill downshifts though, it's just *that* much smoother (if I get it right <g>). Jan. =--- Alan wrote...

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> IIRC there was an 'optimal' revs that stopped clutchless > changing from screwing your Gearbox, something around the > 5600 revs mark in my old Vauxhall. > > I gave up messing with stuff like RL LFB'ing and clutchless > changing when I realised I was being serious danger to > others and myself ;) > > Alan.

#> You are confusing trailbraking with heel and toeing. #> <snip> I see. Care to explain them? :) Thx. Shellfer.

Ok, I'll save the post and your correction for the time being while I double check and correct some things/words myself. Jan. =--- Gregor Veble wrote...

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> Wonderful post, my suggestion is to put it somewhere on > the net so the next time the issue arises only a link > may be posted. > > Just a minor correction, with applying the throttle you > do not as much shift the weigth as you alter the brake > ballance. On a RWD car, the torque of the engine > counteracts the brake action on the rear axis, so the > effective brake ballance is put forward, which helps > counter the oversteer. On a FWD car, applying the throttle > when braking will actually produce oversteer tendencies as > it is the front axle where braking is reduced thus shifting > the brake ballance rearwards, and can be used to help at > turn-in, as front engined, front wheel drive cars > typically tend to understeer. > > -Gregor

LOL.... Interesting suggestion. Jan. =--- Andre Warringa wrote...

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> <snip> > Wow bud, thanks for explaining, had to read your > post twice but it made things a lot clearer to me. > You should write a book about this. Now we only > need a title... how about 'Read to win'? > > Andre > > >Jan. >

Right, are you sitting comfortably? -Because we'll need to go through a little theory to explain. Heel-toe: When you shift your road car there are special rings in the gearbox, synchromesh rings, that serve to match the speed of the input shaft (set of gears connected to the engine, which turn at engine speed) to that of the output shaft (set of gears connected to the wheels, which turn at road speed) so that the next pair of gears can engage successfully. As you clutch your engine is disconnected from the input shaft, which is accelerated / decelerated to the speed of the output shaft, gears engage and, as you let the clutch out again, engine revs are matched to the speed of the gearbox. So far so good, but racing gearboxes need to be light, so there can't be much in the way of extra components to get the job done. They solve the problem of different shaft speeds in an other way, by means of "dog" rings (rings with swallow tail shape teeth, with rather large gaps in between) which are moved between gears to engage the "next" pair. The gears themselves are also different for economy and durability reasons. Racing engines are quite powerful and, because they have a light flywheel, they accelerate and decelerate very quickly. They also don't have much in the way of an idle setting so when the throttle is shut they don't get mixture and therefore resist being accelerated by outside forces. It's therefore important to have engine revs somewhat in the region of the speed of the gearbox when you engage the clutch again. When shifting using a clutch (I will come to clutchless shifting in a minute) going up the box is therefore not much of a problem, you just let up on the accelerator when you shift (also to avoid an overrev), engine revs drop and with a little practise you won't feel much of a jolt when you let the clutch out (becomes 2nd nature almost instantly). Going down the box is another matter, as your right foot will be on the brake and you need to get the revs up higher than they were at the time you pressed the clutch. If you don't you'll snatch (i.e. drag) the rear tyres as they attempt to accelerate the engine. At it's most benign, this will only upset the car somewhat, ranging from spins to actual damage to engine and gearbox as engines get more powerful and tyres wider. Right, so we've established the need to blip the throttle on downshifts in race cars. So how does one go about it? -Well, in the olden days (pre-WWII) Italian race cars had the accelerator in the middle and the brake to the right and more towards the driver. The driver therefore put his heel on the brake and blipped the throttle with his toes has he attempted to slow a ludicrously heavy and hideously overpowered monster using totally inadequate drum brakes, hence "Heel-Toe". In more modern times, with central brake pedals, drivers use what Ayrton Senna calls the "Sole-Sole" technique: the "ball" of the right foot is on the brake while the driver blips the throttle with the right edge of same. If you've been paying attention you will have sussed you can engage gears without using the clutch, provided you use the engine to match the speed of the input shaft to that of the output shaft while the box is in neutral (easier than it sounds with dog boxes). Not using the clutch frees the left foot for operating the brake (which has other advantages) the so called "left foot braking" technique (LFB). Obviously the right operates the throttle exclusively so blipping shouldn't be a problem. Trail braking : Tyres provide grip in all directions, not just along the thread ( pure acceleration / braking) or perpendicular to the thread (pure cornering), but also at a combination of cornering and braking force. However the resulting vector can not exceed the maximum grip in either of the "pure" situations. If you plot it for all possible combinations in a "g-g"-diagram you will find it roughly produces a circle, the so called traction circle (do a search on the web for an illustration). With this in mind, if you go by the old dictum of "getting all of your braking done in a straight line", you're not using your tyres to their full capacity as you move along the axis of the g-g diagram as opposed to the perimeter of the traction circle. You therefore need to reduce braking smoothly as cornering force increases, i.e. you must "trail" the brakes going into the corner. Likewise you must reduce cornering demand as you attempt to get the power on the road, i.e. "release the car early" to get maximum drive out of the corner (this comes more natural to most drivers). That said, it's not an easy thing to do, because of weight shifts in your car. This is another area where LFB shines... as the driver trailbrakes deep into the corner using his left foot, the right foot can balance the car using the accelerator to effectively shift weight back to the rear of the car, reducing the risk of swapping ends because of the late brake application. Do not confuse LFB with trailbraking, however, LFB can be used to trailbrake more effectively, but it's not the same thing. Hope that makes it a little clearer, Jan. =--- Shellfer wrote...

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> #> You are confusing trailbraking with heel and toeing. > #> <snip> > > I see. Care to explain them? :) > > > Thx. > Shellfer. >

Jan Verschueren wrote: <snipping a brilliant post>

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> This is another area where LFB shines... as the driver trailbrakes deep > into the corner using his left foot, the right foot can balance the car > using the accelerator to effectively shift weight back to the rear of the > car, reducing the risk of swapping ends because of the late brake > application. Do not confuse LFB with trailbraking, however, LFB can be used > to trailbrake more effectively, but it's not the same thing. > > Hope that makes it a little clearer, > > Jan.

Wonderful post, my suggestion is to put it somewhere on the net so the next time the issue arises only a link may be posted. Just a minor correction, with applying the throttle you do not as much shift the weigth as you alter the brake ballance. On a RWD car, the torque of the engine counteracts the brake action on the rear axis, so the effective brake ballance is put forward, which helps counter the oversteer. On a FWD car, applying the throttle when braking will actually produce oversteer tendencies as it is the front axle where braking is reduced thus shifting the brake ballance rearwards, and can be used to help at turn-in, as front engined, front wheel drive cars typically tend to understeer. -Gregor

On Mon, 14 Aug 2000 15:02:09 +0200, "Jan Verschueren" <[email hidden]> wrote: <snip long but very clear explanation> >Hope that makes it a little clearer, Wow bud, thanks for explaining, had to read your post twice but it made things a lot clearer to me. You should write a book about this. Now we only need a title... how about 'Read to win'? Andre >Jan.