brake knockback

[n1gzd]

It appears in this foot cam video of a V8 supercar driver that he sometimes taps the brake with his left foot a moment before he brakes hard with his right foot in order to ensure that there are no knockback delays:



Rebecca

[jeffw]

Yup. I do that at corners where I know i've had issues, or if i feel like i've hit the curbing particularly hard. Well worth it.

[brucesallen]

He needs better brakes. Floating calipers would prevent this. Doesn't happen in Formula 1.

[Chrispy]

I think you meant floating rotors? A full floating setup does greatly reduce knockback but I don't think it's a guaranteed 100% solution, it just increases the allowable flex in the system.

He may not even need to do it in that particular car, but old habits die hard.

[wizzman]

I have yet to notice this at all, even at Watkins Glen where this is supposedly experienced due to the big boy rumbles.

[Mick]

I think the size of your master cylinder is a factor in how much the deflection can be felt in the pedal.

[wizzman]

I think the size of your master cylinder is a factor in how much the deflection can be felt in the pedal.

That's what she said

[horizenjob]

Maybe it's because of the fenders, they cause all sorts of problems. I don't even think I could do this because the steering shaft goes between the pedals. Good brakes are so nice to have and one of the best brake upgrades is getting rid of a couple thousand pounds of your car. Fenders on a car are like lead weights on a dancer...

[CP]

I've experienced this a number of times in my Spec Miata with the stock braking system. Left-foot tapping has become second nature.

[brucesallen]

Maybe it's because of the fenders, they cause all sorts of problems. I don't even think I could do this because the steering shaft goes between the pedals. Good brakes are so nice to have and one of the best brake upgrades is getting rid of a couple thousand pounds of your car. Fenders on a car are like lead weights on a dancer...

racers with fenders are wussies.

[horizenjob]

racers with fenders are wussies.

It's fun to bash the other guys. I really want to encourage people to get in cars that are made for track use though. It's difficult to describe how much better car's like ours work. If you're having to left brake before you even get to corners, just to know if you have brakes or to pump up the pedal - how do you really know that you don't have a big problem just waiting to bite you?

I have both a total brake failure and a throttle jam wide open and neither was a fun experience. I am glad the throttle jam happened on my FF though, I was able to come to a full stop before the wall. I don't think a street car would have been able to carry that off. Their weight, momentum and generally over loaded components really reduce safety factors.

My FF runs the front wheel bearings with a lot of play, enough so that it's often mentioned in tech inspection in street car clubs like COM. The wheels can probably clunk back and forth 1/8" or so. It never has pad knockback though, or not that I have ever thought about anyway. The brake pedal has always felt like it has a brick underneath it when I use it.

I don't think braking zones in that car last for more then 1 second, often less. When you hit the brakes it feels like a gorilla tossed you against a wall, then you turn. It's so quick that that is what you have to learn to get it right.