Left foot braking?
Discussion
I would like to ask about left foot braking. I have used this from time to time both on track and on road with varying success and would like to ask for other opinions on its use and advantages.
The main reason I use it is to modulate vehicle when in the mid to exit of the corner and I find that this works quite well in my g/f's Leon FR when makig progress as it reduces understeer and seems to increase grip however this may just be a by product of less understeer appearing to give more grip. I find that this is easier than using the throttle to modulate the vehicle as it works faster and also reduces the risk of lift off oversteer if done gently and also allows revs to be kept u with less lag when getting back on the gas.
That is my experience of this, can I ask if anyone has similar thoughts, especially with its use with RWD vehicles?
I've also heard it said it can reduce wheel spin on the unloaded wheel. It is mentioned in this video for instance.
http://youtu.be/vcSAiRxmm0w
The main reason I use it is to modulate vehicle when in the mid to exit of the corner and I find that this works quite well in my g/f's Leon FR when makig progress as it reduces understeer and seems to increase grip however this may just be a by product of less understeer appearing to give more grip. I find that this is easier than using the throttle to modulate the vehicle as it works faster and also reduces the risk of lift off oversteer if done gently and also allows revs to be kept u with less lag when getting back on the gas.
That is my experience of this, can I ask if anyone has similar thoughts, especially with its use with RWD vehicles?
I've also heard it said it can reduce wheel spin on the unloaded wheel. It is mentioned in this video for instance.
http://youtu.be/vcSAiRxmm0w
That's an interesting video - a couple of observations...
Firstly, as Chris Harris says in the video, the Focus RS is fitted with a torsen differential, which, although not unique, is quite a specialised piece of kit in a FWD road car. Contemporary road tests of the mk1 Focus RS showed it to have some unusual characteristics for a FWD hot hatch, particularly when exiting low to medium speed corners, where the car had a tendency to torque steer. Left foot braking is one method of controlling torque steer, but another, of course, is to be a little less clog-footed with the throttle until the car is pointing a little more straight.
The other observation is that Chris Harris is a very experienced test and race driver, who has had the opportunity to try these techniques in the safer confines of a track before taking them on the road. There is some benefit to racing drivers in braking with the left foot - as Chris points out, it pretty much removes any delay between braking and accelerating, and actually allows some overlap between those two phases, which is advantageous when you're trying to lose a few tenths from your lap times.
For the road, however, I don't personally see any benefit in left foot braking, as there are too many other variables out there to prevent you from driving right up to the limits of your car.
As for understeer, left foot braking will, of course, transfer the vehicles weight towards the front wheels, but the danger is that if you try it for the first time when you're suffering understeer, your untrained left foot will hoof down on the brake pedal in the same way it's been doing on the clutch pedal for years. If you're understeering, a full-on brake application could easily pitch you into severe oversteer before you have time to react.
If you do find yourself understeering on the road, in most cases a lift off the accelerator should move enough weight forward to regain some grip for the front wheels. If you're still understeering after you've lifted off the gas, then a gentle application of the brakes should sort things out. Whether you do this with your left or right foot is up to you, but if things are going wrong, it's better to fall back on the skills you don't have to actually think about, so I'd stick with the right foot.
Firstly, as Chris Harris says in the video, the Focus RS is fitted with a torsen differential, which, although not unique, is quite a specialised piece of kit in a FWD road car. Contemporary road tests of the mk1 Focus RS showed it to have some unusual characteristics for a FWD hot hatch, particularly when exiting low to medium speed corners, where the car had a tendency to torque steer. Left foot braking is one method of controlling torque steer, but another, of course, is to be a little less clog-footed with the throttle until the car is pointing a little more straight.
The other observation is that Chris Harris is a very experienced test and race driver, who has had the opportunity to try these techniques in the safer confines of a track before taking them on the road. There is some benefit to racing drivers in braking with the left foot - as Chris points out, it pretty much removes any delay between braking and accelerating, and actually allows some overlap between those two phases, which is advantageous when you're trying to lose a few tenths from your lap times.
For the road, however, I don't personally see any benefit in left foot braking, as there are too many other variables out there to prevent you from driving right up to the limits of your car.
As for understeer, left foot braking will, of course, transfer the vehicles weight towards the front wheels, but the danger is that if you try it for the first time when you're suffering understeer, your untrained left foot will hoof down on the brake pedal in the same way it's been doing on the clutch pedal for years. If you're understeering, a full-on brake application could easily pitch you into severe oversteer before you have time to react.
If you do find yourself understeering on the road, in most cases a lift off the accelerator should move enough weight forward to regain some grip for the front wheels. If you're still understeering after you've lifted off the gas, then a gentle application of the brakes should sort things out. Whether you do this with your left or right foot is up to you, but if things are going wrong, it's better to fall back on the skills you don't have to actually think about, so I'd stick with the right foot.
I knew there was something I forgot to add - brake override systems.
In 2009, Toyota recalled many thousands of cars due to a number of "unintended acceleration" accidents in the US. Car makers try to keep things as simple as possible for our American cousins by supplying mostly automatics with only two pedals to keep confusion to a minimum, but it seems that they can still get things badly wrong, and they like to blame the manufacturers whenever possible. Whether the vehicles involved in these accidents actually had a throttle problem, or if they just got stuck under the carpet, or if the driver simply got the "go" and "stop" pedals mixed up, we'll never know, but the legacy of these accidents and the Toyota recall is the "brake override system".
These electronic systems simply cut the throttle to tickover if you apply the brake whilst the accelerator is depressed. It's a simple enough safety system, and you'd probably be very happy with it if your throttle pedal jammed wide open, and you pressed the brakes, so for 99% of drivers it makes perfect sense.
It will completely mess up left foot braking though, so it's another reason not to attempt it on the road.
In 2009, Toyota recalled many thousands of cars due to a number of "unintended acceleration" accidents in the US. Car makers try to keep things as simple as possible for our American cousins by supplying mostly automatics with only two pedals to keep confusion to a minimum, but it seems that they can still get things badly wrong, and they like to blame the manufacturers whenever possible. Whether the vehicles involved in these accidents actually had a throttle problem, or if they just got stuck under the carpet, or if the driver simply got the "go" and "stop" pedals mixed up, we'll never know, but the legacy of these accidents and the Toyota recall is the "brake override system".
These electronic systems simply cut the throttle to tickover if you apply the brake whilst the accelerator is depressed. It's a simple enough safety system, and you'd probably be very happy with it if your throttle pedal jammed wide open, and you pressed the brakes, so for 99% of drivers it makes perfect sense.
It will completely mess up left foot braking though, so it's another reason not to attempt it on the road.
Edited by R_U_LOCAL on Sunday 1st June 09:22
Edited by R_U_LOCAL on Sunday 1st June 09:23
Left Foot Braking - in an auto
Here's a different view - I am a professional independent chauffeur spending
Nearly all my time driving in Central London
I LFB all the time. It stems from driving in SEG convoys with a full car or MPV and the need to keep the revs
Up in order to keep pace with the lead vehicle and to keep the convoy gaps tight.
Anyway I now find it totally natural and aids a smooth ride and provides a quicker response when pulling
out at junctions or roundabouts etc.
Never has a single client noticed but more often the comment on the smoothness and rapid progress
of the drive
It does take practice to get it right....
Here's a different view - I am a professional independent chauffeur spending
Nearly all my time driving in Central London
I LFB all the time. It stems from driving in SEG convoys with a full car or MPV and the need to keep the revs
Up in order to keep pace with the lead vehicle and to keep the convoy gaps tight.
Anyway I now find it totally natural and aids a smooth ride and provides a quicker response when pulling
out at junctions or roundabouts etc.
Never has a single client noticed but more often the comment on the smoothness and rapid progress
of the drive
It does take practice to get it right....
I know with all the threads on here regarding BGOL that people will probably disagree with what I am going to say here but I use left foot braking. Sometimes, I will downshift with a blip of the throttle and no brakes to make a nice noise and get some engine braking, then I need to turn into a junction or a tight corner instead of braking with my right foot as I approach to turn in then have that coasting moment as you go from brake to accelerator and slight jerkiness as you touch the accelerator again I will scrub some speed off with my left foot on the brake instead. Then when I want to accelerate through the junction or corner I can start doing this simultaneously as I come off the brake.
Not explained very well but I promise it is smoother, it is kind of pointless because you can only really use it where you have visibility, don't want an unexpected hazard and end up pushing the wrong pedal or stalling by not depressing the clutch but it is fun and is a nice slow speed way to build up the use of left foot braking and make you feel like a rally driver.
I have tried the Chris Harris through the corner thing but to be honest I am not good enough to do it flat out, so when I do it I am not going fast enough to need it if that makes sense. I have tried it whilst wheelspinning in second gear as a traction control like thing but it is easier just not to break traction in the first place, or lift slightly. It feels like it works in my car with a LSD but then that may just be because I am slowing slightly and tucking the nose in.
Fun to try, and I think we should all be open to trying different techniques as well as different ideas when driving but I am more in the camp it is for racing drivers to get the backend out, and not needed on the road. As I said in my first paragraph it can be used to be very smooth going from braking to accelerating, particularly in a corner but you can plan around the necessity of doing this by braking and gear changing first.
Not explained very well but I promise it is smoother, it is kind of pointless because you can only really use it where you have visibility, don't want an unexpected hazard and end up pushing the wrong pedal or stalling by not depressing the clutch but it is fun and is a nice slow speed way to build up the use of left foot braking and make you feel like a rally driver.
I have tried the Chris Harris through the corner thing but to be honest I am not good enough to do it flat out, so when I do it I am not going fast enough to need it if that makes sense. I have tried it whilst wheelspinning in second gear as a traction control like thing but it is easier just not to break traction in the first place, or lift slightly. It feels like it works in my car with a LSD but then that may just be because I am slowing slightly and tucking the nose in.
Fun to try, and I think we should all be open to trying different techniques as well as different ideas when driving but I am more in the camp it is for racing drivers to get the backend out, and not needed on the road. As I said in my first paragraph it can be used to be very smooth going from braking to accelerating, particularly in a corner but you can plan around the necessity of doing this by braking and gear changing first.
tvrwedgehead said:
It stems from driving in SEG convoys with a full car or MPV and the need to keep the revs
Up in order to keep pace with the lead vehicle and to keep the convoy gaps tight.
If by SEG you mean Special Escort Group, then I'd suggest your driving skills will be in a completely different league to mere mortals. Thus, what works for a former SEG member mightn't be appropriate for many civilian drivers.Up in order to keep pace with the lead vehicle and to keep the convoy gaps tight.
It might be worth pointing out at this point in relation to the video of Chris Harris with the Mk1 Focus RS that when he first drove it at the Ford test track in Belgium, he did have a rather closer than intended encounter with one of the gravel traps and a section of barrier. Not a lot of damage to the car - slightly bent front wing which the mechanics were threatening to sign and present to Chris as a memento (not sure if they did or not). Chris was at least honest enough to write "lack of driver talent" as the cause of the accident in the accident book 
.
I guess the point is as per the earlier comments the value of left foot braking only really comes at or near the limit which isn't necessarily where you want to be on public road. That said in a Mk 1 RS on a track left foot braking is immense fun and does allow you to carry more speed through the corners.
.I guess the point is as per the earlier comments the value of left foot braking only really comes at or near the limit which isn't necessarily where you want to be on public road. That said in a Mk 1 RS on a track left foot braking is immense fun and does allow you to carry more speed through the corners.
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