Threshold braking – how to get it right
Threshold braking is the art of slowing down in the quickest possible way by maintaining brake force at the optimum level. It's tricky and requires a lot of practise in a familiar car before you'll be able to do it reliably, but braking late before a corner is one of the easiest methods of getting decent track times.
But first, two quick facts:
So, how does one learn this strange and wonderful technique?
Stage one
First you need to become familiar with the point of wheel lock in your car, which means finding suitably safe area of privately owned tarmac to practice on. Brake hard in a straight line at different speeds (30mph is a good starting point) and get a feel for how the car reacts under rapid braking to the point of wheel lock. Don't stamp on the pedal, but rather apply push it firmly and progressively. Get the answers to the following questions clear in your own mind:
Stage two
Now you're familiar with the sensation of braking hard enough to lock wheels in your car or activate the ABS. Remember, as soon as wheels lose traction with the tarmac you're no longer braking efficiently - but even the best drivers lock wheels from time to time. So, it's important to learn how to regain maximum friction as quickly as possible when this situation arises.
Accelerate to a slightly higher speed (say 50mph) and repeat the process of inducing wheel lock. Try to get to the point of lock as quickly as you can without upsetting the balance of the car. But rather than simply screeching to a halt, release the brake slightly to free up the locked wheel(s), then reapply at a slightly reduced pressure to try and maintain decent braking performance.
Get to the point when you can reliably reduce the brake pressure and reapply the brakes in as little time as possible. Some ABS systems may make this process difficult due to built in delays in the electronics, and it might be at this point when you decide threshold braking isn't for you after all!
Stage three
Now you will have a good feel for the car, appreciate the sensation of heavy braking and understand the point of wheel lock, so it's time to do the perfect run. Accelerate back up to around 50mph and repeat the process of braking heavily, but this time try to come to a halt as quickly as you can without locking any wheels. Remember, a little bit of tyre screech is ok, as long as the wheels haven't locked.
If a wheel does stop rotating, use the 'release and reapply' technique to maintain control of the car.
Repeat as many times as you need to until you can brake reliably without locking wheels – give yourself a pat on the back and check your tyres for wear and tear before going back on the public roads.
Now all you need to know is how to do it in different track conditions!
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But first, two quick facts:
- Locked wheels are not the most efficient method of slowing down (lots of tyre screech is bad)
- Tyres exert maximum braking force when slight wheel slip is occurring (some tyre screech is ok)
So, how does one learn this strange and wonderful technique?
Stage one
First you need to become familiar with the point of wheel lock in your car, which means finding suitably safe area of privately owned tarmac to practice on. Brake hard in a straight line at different speeds (30mph is a good starting point) and get a feel for how the car reacts under rapid braking to the point of wheel lock. Don't stamp on the pedal, but rather apply push it firmly and progressively. Get the answers to the following questions clear in your own mind:
- How hard do you need to push the pedal for wheels to lock (or ABS to kick in)?
- What is the sensation just before the point of wheel lock?
- When wheels do start to lock up, what are the warning factors?
- Which wheels lock up first?
- How does the car behave when a wheel has locked?
- Is there any feedback from the brake pedal?
Stage two
Now you're familiar with the sensation of braking hard enough to lock wheels in your car or activate the ABS. Remember, as soon as wheels lose traction with the tarmac you're no longer braking efficiently - but even the best drivers lock wheels from time to time. So, it's important to learn how to regain maximum friction as quickly as possible when this situation arises.
Accelerate to a slightly higher speed (say 50mph) and repeat the process of inducing wheel lock. Try to get to the point of lock as quickly as you can without upsetting the balance of the car. But rather than simply screeching to a halt, release the brake slightly to free up the locked wheel(s), then reapply at a slightly reduced pressure to try and maintain decent braking performance.
Get to the point when you can reliably reduce the brake pressure and reapply the brakes in as little time as possible. Some ABS systems may make this process difficult due to built in delays in the electronics, and it might be at this point when you decide threshold braking isn't for you after all!
Stage three
Now you will have a good feel for the car, appreciate the sensation of heavy braking and understand the point of wheel lock, so it's time to do the perfect run. Accelerate back up to around 50mph and repeat the process of braking heavily, but this time try to come to a halt as quickly as you can without locking any wheels. Remember, a little bit of tyre screech is ok, as long as the wheels haven't locked.
If a wheel does stop rotating, use the 'release and reapply' technique to maintain control of the car.
Repeat as many times as you need to until you can brake reliably without locking wheels – give yourself a pat on the back and check your tyres for wear and tear before going back on the public roads.
Now all you need to know is how to do it in different track conditions!