Left foot braking for the road with a manual transmission
Discussion
Who is doing this and why? I had a drive with a police driving instructor recently who did this safely and smoothly and am considering trying it. I have been left foot braking in automatics for years.
For:
Quicker braking reaction in extremis, though a well planned drive should mean this should never be needed, though sh** happens
It facilitates trail braking and keeps the car balanced into a corner
Great to help turning in with understeer prone cars, especially on track
Against:
An emergency would require a rapid foot change to press the clutch pedal
Requires a wider brake pedal?
As above, good planning should mean that trail braking and gear changing in a corner isn’t needed.
Understeer should not be an issue on a public road where good safety margins are used
Discuss
For:
Quicker braking reaction in extremis, though a well planned drive should mean this should never be needed, though sh** happens
It facilitates trail braking and keeps the car balanced into a corner
Great to help turning in with understeer prone cars, especially on track
Against:
An emergency would require a rapid foot change to press the clutch pedal
Requires a wider brake pedal?
As above, good planning should mean that trail braking and gear changing in a corner isn’t needed.
Understeer should not be an issue on a public road where good safety margins are used
Discuss
I can’t really discuss road use of LFB as I hardly ever do it and haven’t for years. However I was lucky enough to spend a day with Pentti Airikkala to learn about LFB in a competition environment.
It boils down to speed of transition from throttle to brake and back to throttle. It’s quicker and therefore should be quicker over a lap. However that’s a very basic assumption and LFB can be used on the way out of corners to keep the weight over the nose.
However there’s a lot more to balancing a car than riding the brakes going into a corner- that automatically can create over steer as the back is unloaded.
There is a school of thought taught by the likes of Rob Wilson and John Steven’s ( who I have also had tuition from) that it is possible to transition from brake to throttle too quickly . Indeed it is the basis of the ‘flat car’ mantra that Rob Wilson espouses. Essentially that if you RFB, you have a point in the transition from brake to throttle whereby you are neither on the brake nor the throttle.. and there the car has its most grip as all four tyres are pressed equally into the ground. Allowing you to get on the throttle harder and faster.
So LFB rewards those that want to find time on the brakes and RFB when used properly can be used to find time in the acceleration zones. As a track is mostly acceleration zones, it’s the difference between perfecting 30% of the lap or 70% of the lap.
On the road, really not sure there is much of an advantage but it could be useful for corners that unexpectedly tighten up on you.
It boils down to speed of transition from throttle to brake and back to throttle. It’s quicker and therefore should be quicker over a lap. However that’s a very basic assumption and LFB can be used on the way out of corners to keep the weight over the nose.
However there’s a lot more to balancing a car than riding the brakes going into a corner- that automatically can create over steer as the back is unloaded.
There is a school of thought taught by the likes of Rob Wilson and John Steven’s ( who I have also had tuition from) that it is possible to transition from brake to throttle too quickly . Indeed it is the basis of the ‘flat car’ mantra that Rob Wilson espouses. Essentially that if you RFB, you have a point in the transition from brake to throttle whereby you are neither on the brake nor the throttle.. and there the car has its most grip as all four tyres are pressed equally into the ground. Allowing you to get on the throttle harder and faster.
So LFB rewards those that want to find time on the brakes and RFB when used properly can be used to find time in the acceleration zones. As a track is mostly acceleration zones, it’s the difference between perfecting 30% of the lap or 70% of the lap.
On the road, really not sure there is much of an advantage but it could be useful for corners that unexpectedly tighten up on you.
Panamax said:
You'll have loads of fun in a modern German car. They shut the throttle as soon as you touch the brake.
Luckily, my German car is old enough that I need a serious amount of both pedals before the software cuts the throttle. I was able to test that theory at Millbrook before Christmas with CAT Driver Training.Dynion Araf Uchaf said:
I can’t really discuss road use of LFB as I hardly ever do it and haven’t for years. However I was lucky enough to spend a day with Pentti Airikkala to learn about LFB in a competition environment.
I spent some time driving Pentti around on WRC events as his VIP driver. No pressure. 
He was a great character.
brisel said:
Who is doing this and why? I had a drive with a police driving instructor recently who did this safely and smoothly and am considering trying it. I have been left foot braking in automatics for years.
For:
Quicker braking reaction in extremis, though a well planned drive should mean this should never be needed, though sh** happens
It facilitates trail braking and keeps the car balanced into a corner
Great to help turning in with understeer prone cars, especially on track
Against:
An emergency would require a rapid foot change to press the clutch pedal
Requires a wider brake pedal?
As above, good planning should mean that trail braking and gear changing in a corner isn’t needed.
Understeer should not be an issue on a public road where good safety margins are used
Discuss
I suppose if someone is tailgating you and won’t back off, a quick tap on the break with the left foot whilst accelerating may cause the driver behind to back off. I say’may’ but it does work! For:
Quicker braking reaction in extremis, though a well planned drive should mean this should never be needed, though sh** happens
It facilitates trail braking and keeps the car balanced into a corner
Great to help turning in with understeer prone cars, especially on track
Against:
An emergency would require a rapid foot change to press the clutch pedal
Requires a wider brake pedal?
As above, good planning should mean that trail braking and gear changing in a corner isn’t needed.
Understeer should not be an issue on a public road where good safety margins are used
Discuss
There is a world of difference between LFB on the road and LFB on the track. A track is actually a fairly predictable environment, with only a handful of braking points. On the track, you are going to have to brake for the exact same corners every time. The only difference is minor variations of exactly when you are getting on the brakes and a little bit of pedal modulation. Your commute to work or your drive to the shops is much more chaotic and likely includes dozens of random braking points. You could need to be on the brakes at any moment, from just a dab to a full on emergency stop. And the benefits you gain by LFB in traffic are minuscule, at best. If you are going to do it, I would suggest you spend A LOT of time developing the skill on track or in some other controlled environment. Ease into it on deserted stretches of road when no other drivers are around. You have to develop the muscle memory, otherwise, you will get yourself crossed up in the real world and potentially cause an accident.
Personally, the only time I really focus on LFB on the track is corners where I know there won't be any gear change involved. For anything involving downshifting, I just use heel and toe techniques.
Personally, the only time I really focus on LFB on the track is corners where I know there won't be any gear change involved. For anything involving downshifting, I just use heel and toe techniques.
Edited by mko9 on Thursday 4th January 08:11
It is very occasionally useful in very specific circumstances but invariably unless you are using it all the time you apply too much pressure.
IN all honesty it is fairly useless in modern cars.
But in rallying and even in most other forms of motorsport a lot of drivers use it.
it came from fwd cars and Mini's really and was a way of opening the corner to a fwd car instead of just waiting to wind the understeer off!
IN all honesty it is fairly useless in modern cars.
But in rallying and even in most other forms of motorsport a lot of drivers use it.
it came from fwd cars and Mini's really and was a way of opening the corner to a fwd car instead of just waiting to wind the understeer off!
I use LFB in two pedal vehicles, not in three pedal ones.
Another veteran of a Pentti Airikkola LFB day here. One of the situations in which he advocated LFB was with front wheel drive on a loose surface. By applying brakes and power together on a bend you generate slip at the back and can fine tune the trajectory of the car - more brakes, more turn-in. I found this very effective on ice driving trips to Sweden. I have never used this in the UK.
On LFB in two pedal vehicles, as others have said if the technique is new to you you need to 'learn' it cautiously - two reasons, you need to build up the muscle memory progressively, and while you are doing so (and avoiding using the brake pedal like a clutch, which throws you forwards violently) it uses up more brain power. Once learned, it has marginal advantages; it is certainly pleasant to use on a swift rural drive, and there is a tiny safety benefit in covering the brake at a time when you would otherwise take a second to transition from accelerator pedal to brake.
On LFB in three pedal vehicles, if you only do it where you are confident you will not need to brake there is hardly any advantage. To do it where you may need to brake requires exceptional skill. There is a wonderful video online somewhere of Walter Rohrl in an Audi Sport Quattro using LFB and transitioning seamlessly to RFB when he needed to change gear. Using an ordinary manual style brake pedal, he was able to change from braking with the left foot to braking with the right foot when he needed to start a heel and toe gear change. The same skill would let you declutch if you had to emergency brake to a standstill. I have seen this done well by a very good driver on the road. However again there would be a steep learning curve and the potential benefit is only marginal. Using only half the brake pedal for each foot must also involve at least some level of risk of the foot slipping off the brake pedal at just the wrong moment.
Another veteran of a Pentti Airikkola LFB day here. One of the situations in which he advocated LFB was with front wheel drive on a loose surface. By applying brakes and power together on a bend you generate slip at the back and can fine tune the trajectory of the car - more brakes, more turn-in. I found this very effective on ice driving trips to Sweden. I have never used this in the UK.
On LFB in two pedal vehicles, as others have said if the technique is new to you you need to 'learn' it cautiously - two reasons, you need to build up the muscle memory progressively, and while you are doing so (and avoiding using the brake pedal like a clutch, which throws you forwards violently) it uses up more brain power. Once learned, it has marginal advantages; it is certainly pleasant to use on a swift rural drive, and there is a tiny safety benefit in covering the brake at a time when you would otherwise take a second to transition from accelerator pedal to brake.
On LFB in three pedal vehicles, if you only do it where you are confident you will not need to brake there is hardly any advantage. To do it where you may need to brake requires exceptional skill. There is a wonderful video online somewhere of Walter Rohrl in an Audi Sport Quattro using LFB and transitioning seamlessly to RFB when he needed to change gear. Using an ordinary manual style brake pedal, he was able to change from braking with the left foot to braking with the right foot when he needed to start a heel and toe gear change. The same skill would let you declutch if you had to emergency brake to a standstill. I have seen this done well by a very good driver on the road. However again there would be a steep learning curve and the potential benefit is only marginal. Using only half the brake pedal for each foot must also involve at least some level of risk of the foot slipping off the brake pedal at just the wrong moment.
I've practiced this as a driving skill I wanted to be able to do, but in reality find almost no use for it day to day.
On the road you're not, and should never be intentionally near the limit of driving anyway in order to justify it to make use of the benefits when you exit a corner more quickly by moving the weight, controlling understeer and such. It's more about fun and smoothness than anything else.
The first times you try it, you'll probably almost put yourself through the windscreen. After a bit of practice, it becomes like right foot braking and you notice your clutch control improves too.
In a two pedal car, it's my default thing to do if I'm intent on a spirited drive providing the ECU doesn't cut the throttle when you dab the brakes. Day to day, rolling off the throttle on to the brake is usually pretty leisurely and always covering the brake doesn't seem to offer any significant benefit. If I'm having to be concerned with the benefit of shaving a tenth or two off my reaction time vs getting my right foot over, what's on the way to hit me is almost certainly still going to hit me.
In a three pedal car, it depends on the car. Left foot in a series of nice 2nd or 3rd gear lunges between bends where you can stay in the power band feels nice. The foot acrobatics when you do need to change can make you feel confident in your driving abilities in a good way. It takes a bit more brain power, a bit more thought, and possibly leads to better decision making about what you're doing with your feet at a given time because you're always thinking about it a bit more.
When I say it depends on the car - in the TVR I very rarely left foot brake on the road. I heel and toe, working up and down the gears to keep it simmering in the upper half, enjoying the glorious noise. The sharpness and lightness of the brakes against the relative heaviness of the clutch isn't a great combination of pedal feels to dodge between, and with no ABS to help if I lock up, getting it wrong out in public doesn't leave much margin for error. Plus, I'm always able to be back up to the speed limit between corners even if they're very close together, so I'd be going a bit quicker if I made a mistake too.
Cars that feel a bit more normal to drive, with probably 150-200bhp/tonne are for me where I think the sweet spot is for doing that in a 3 pedal car on the road and enjoying it.
There's actual no use/need for it at all on the road in terms of car control for us. As a thing to be able to do, so long as you're not endangering anybody, have fun and hopefully enjoy some benefits from keeping the skill up to do it on a track day.
On the road you're not, and should never be intentionally near the limit of driving anyway in order to justify it to make use of the benefits when you exit a corner more quickly by moving the weight, controlling understeer and such. It's more about fun and smoothness than anything else.
The first times you try it, you'll probably almost put yourself through the windscreen. After a bit of practice, it becomes like right foot braking and you notice your clutch control improves too.
In a two pedal car, it's my default thing to do if I'm intent on a spirited drive providing the ECU doesn't cut the throttle when you dab the brakes. Day to day, rolling off the throttle on to the brake is usually pretty leisurely and always covering the brake doesn't seem to offer any significant benefit. If I'm having to be concerned with the benefit of shaving a tenth or two off my reaction time vs getting my right foot over, what's on the way to hit me is almost certainly still going to hit me.
In a three pedal car, it depends on the car. Left foot in a series of nice 2nd or 3rd gear lunges between bends where you can stay in the power band feels nice. The foot acrobatics when you do need to change can make you feel confident in your driving abilities in a good way. It takes a bit more brain power, a bit more thought, and possibly leads to better decision making about what you're doing with your feet at a given time because you're always thinking about it a bit more.
When I say it depends on the car - in the TVR I very rarely left foot brake on the road. I heel and toe, working up and down the gears to keep it simmering in the upper half, enjoying the glorious noise. The sharpness and lightness of the brakes against the relative heaviness of the clutch isn't a great combination of pedal feels to dodge between, and with no ABS to help if I lock up, getting it wrong out in public doesn't leave much margin for error. Plus, I'm always able to be back up to the speed limit between corners even if they're very close together, so I'd be going a bit quicker if I made a mistake too.
Cars that feel a bit more normal to drive, with probably 150-200bhp/tonne are for me where I think the sweet spot is for doing that in a 3 pedal car on the road and enjoying it.
There's actual no use/need for it at all on the road in terms of car control for us. As a thing to be able to do, so long as you're not endangering anybody, have fun and hopefully enjoy some benefits from keeping the skill up to do it on a track day.
Edited by NuddyRap on Monday 15th January 15:53
brisel said:
Quicker braking reaction in extremis
You'll be hoping that you don't need to come to a complete stop, as you'll have no feet left to get the clutch down. brisel said:
facilitates trail braking and keeps the car balanced into a corner
Great to help turning in with understeer prone cars, especially on track
It definitely doesn't facilitate trail braking as this is usually done with the right foot. If you're trail-braking you should have no need to be on the throttle. At the vast majority of corners found on circuits, even in an understeer-prone car, you'll have no benefit from having the possibility to press the brake at the same time as the throttle. If you're in a situation where you're see-sawing between the throttle and the brake you've simply approached the corner the wrong way. There are some where it can be of benefit e.g. Coram at Snetterton Great to help turning in with understeer prone cars, especially on track
I'd say zero use on the road.
Just got introduced to this technique in 2023 and would echo a few points here. Firstly, I wouldn't try this on the road until you've experienced it somewhere controlled like a circuit or skid pan. The "The first time you try it, you'll probably almost put yourself through the windscreen" previous quote is very valid, as your left foot in a manual is so conditioned to pushing a pedal further once it senses the car slowing down, to stop it from stalling. Under CAT training's watchful eye at Millbrook however I was using LFB to cure heavy understeer on their dampened circle area, which to me was revelatory as a circuit technique or an OMG road situation (with all the provisos of forward observations etc normally preventing one getting into that situation in the first place.) It was also the perfect illustration that very soon after using the technique you could be split seconds away from a major oversteer moment after unweighting the rear. So for the road, for me, it's a no...
pethedxx said:
Nobody has mentioned the benefit of keeping a turbo spooled up while LFB. Keeping the turbo on boost, especially in AWD and FWD cars while braking is a huge benefit in rallying. Why anyone would want to LFB on the road I don't really understand though but each to their own 
Your brakes don't work properly if you are creating boost whilst braking in a servo assisted car, it relies on the vacuum in the inlet plenum to power the servo boost. To use ALS or on boost braking, you need a none servo assist brake system, rally cars don't use a servo, production based rally cars such as GroupN remove the servo.You dont use the throttle pedal to generate boost during braking, that is done via automatic strategies which alter the engine control to generate boost without generating any torque. If you used a throttle based boost build strategy you would be fighting engine torque with the brakes. The benefit of LFB in that application is speed of change of input and the ability to have some crossover to improve traction and balance.
520TORQUES said:
pethedxx said:
Nobody has mentioned the benefit of keeping a turbo spooled up while LFB. Keeping the turbo on boost, especially in AWD and FWD cars while braking is a huge benefit in rallying. Why anyone would want to LFB on the road I don't really understand though but each to their own
Your brakes don't work properly if you are creating boost whilst braking in a servo assisted car, it relies on the vacuum in the inlet plenum to power the servo boost. To use ALS or on boost braking, you need a none servo assist brake system, rally cars don't use a servo, production based rally cars such as GroupN remove the servo.You dont use the throttle pedal to generate boost during braking, that is done via automatic strategies which alter the engine control to generate boost without generating any torque. If you used a throttle based boost build strategy you would be fighting engine torque with the brakes. The benefit of LFB in that application is speed of change of input and the ability to have some crossover to improve traction and balance.
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