Why do racing drivers tap the brake before a corner?

[_VTEC_]

In a few racing vids I've witnessed drivers tapping the brake pedal a couple of times with their left foot whilst braking with their right foot before the corner.

Anyone know why they do this?

[m12_nathan]

Maybe they were suffering from pad knockback so wanted to get the brakes ready before braking?

[markmullen]

I'm no racing driver but the guys at the PH Caterham slalom day had me braking into corners to put the weight over the front wheels on turn in to assist steering.

[7db]

Had a quick play with left-foot braking this evening.

And left several feet of tyre marks on the A4. Hmmmm. Not very sensitive is the old left foot.

(on the bright side, I did stop quite quickly...)

[petros]

probably to slow down

[_VTEC_]

I think it might be a little test to see if they've got any pedal. To see if the brakes are suffering fade?

[Joe911]

m12_nathan said:

Maybe they were suffering from pad knockback so wanted to get the brakes ready before braking?

Yes - that's what I would guess - described
here

[Don]

m12_nathan said:

Maybe they were suffering from pad knockback so wanted to get the brakes ready before braking?

Yep.

[Mark_SV]

markmullen said:

I'm no racing driver but the guys at the PH Caterham slalom day had me braking into corners to put the weight over the front wheels on turn in to assist steering.

I can think of two possible reasons:
- A bit of brakes can be useful to kill understeer and aid tighter turn-in (as markmullen says).
- Also, the drivers could be trail braking into the turn, likely in order to be able to brake as late as possible.

[RobM77]

I'd like to answer this, as I race; but I don't understand the original post (tapping with the left foot whilst braking with the right - so two feet on one pedal?).

In answer to the other comment yes, braking as you turn will use weight transfer to neutralise the car's steady state handling (usually understeer) into an ideal neutral state. Full on trail braking can also be used for various other reasons (Schumacher is a master of this, and so was Jim Clark).

[huge]

I got told a couple of them do it to spook the guy behind into braking,
thereby losing momentum and gaining precious yards.Its not a popular thing to
have done once you get back to the paddock by all accounts.
On the M25 its known as brake testing !

[_VTEC_]

RobM77 said:

I'd like to answer this, as I race; but I don't understand the original post (tapping with the left foot whilst braking with the right - so two feet on one pedal?). In answer to the other comment yes, braking as you turn will use weight transfer to neutralise the car's steady state handling (usually understeer) into an ideal neutral state. Full on trail braking can also be used for various other reasons (Schumacher is a master of this, and so was Jim Clark).

Sorry, my wording was wrong. Before braking (i.e on straights) I see drivers giving the break pedal a little tap with their left foot (whilst their right foot on the throttle).

I think this question has already been answered so I shall retire.

[alexpez]

Pad knock back sounds pretty reasonable, but most race drivers will tell you its to heat the brakes just before theyre needed.

that stoptech site is great btw, thanks for the link.

pez

[Mr Whippy]

So you won't see many BMW "M" drivers doing it then, but I guess you'll find people who've "upgraded" them suffering pad knock alot more often

You see the drivers in Best Motoring DVD's tapping their brakes alot, but I guess it's also to check for bite and pedal travel after heavy lapping and on a long straight. Last thing you want is a tiny pause or too much travel before they bite when your aiming for a turn in point at 100mph!

Some really good FAQ's there, a great link, thanks!

Dave

[Mastiff]

Joe911 said:

Yes - that's what I would guess - described here

Good page that Joe, thanks.

stoptech said:

In English, when we throw our cars into a corner, stuff bends. It’s not desirable, but that’s the reality of the situation. You can pay more money to make stuff bend less, but it will always bend to some degree.

[slinky]

As an aside (and apologies for the mild hijack)... have you ever tried using the clutch with your right foot??

I know it sounds a little bizarre, and I most certainly wouldn't recommend doing it anywhere near any other traffic... but give it a try...

I was certainly surprised by the level of feedback that exists in the clutch pedal that is completely missed by my somewhat unsensitive clutch foot!

slinky
587racing.com

[DanH]

Your clutch foot is almost certainly more sensitive than your right foot which generally just mashes throttles. Once I was shown left foot braking and had done a little practise, it was easier to modulate the brakes than with the right foot. Balancing a clutch and finding the bite point is harder than working the accelerator...

[RobM77]

I'm not sure that I agree. I found left foot braking quite hard when I first tried it because of the lack of feeling in that foot. Don't forget that you balance a car sideways and threshold brake with your right foot!

[Jungles]

I found left-foot braking difficult to learn too.

The left foot is sensitive when un-pressing the pedal, but not when pressing down on it. Most people just slam the clutch in. The right foot is better exercised for fine control during the downward press, IMHO.

[RobM77]

Yes, I agree. I use the clutch as a switch 95% of the time as I heel and toe on every downchange. I do pull away from rest ok of course, but somehow my left foot just isn't as sensitive as my right. Now I've left foot braked a fair bit my left is better, but still not as sensitive as my right.