Braking and turning in - Trail Braking

[raymondu999]

Yeah I do that too in a lockup. I just didn't see that he had a lockup on screen, that's all.

[N12ck]

Yeah I do that too in a lockup. I just didn't see that he had a lockup on screen, that's all.

you can do that in a non lockup situation, like if you brake later than the braking zone you know you are gonna not have enough grip to slow down if you miss the rubber, so you pump the brakes after you miss the braking zone very quickly to ensure you get your braking done perfectly and dont miss the apex, and make sure you can brake later, but braking on the rubber is preferable,

[jamsbong]

This is a good discussion and I may have some understanding of why Vettel would 'pump' the brakes.
The animation did not show tire smoke from lock up but that does not mean he did not felt lost of grip.

Even before you lock up the tires, you steering force will start to load heavily before weakening. I think drivers don't really use tire smoke as an indication for lock ups, instead they use steering force. This is because you'll felt it first before seeing the smoke. If you use your eyes, it will always be too late.

I believe Vettel felt the steering force changes and decides to loosen up the brake grip by pumping it.

Regarding trail braking. I would expect all drivers in F1 and professional racers to do it. would that be right?? or??

[Sevach]

I think an important factor in trail braking is keeping the weight in the front of the car, when you brake you transfer weight to the front increasing it's grip, but if you release it completely that weight is going back to it's original place, the amount of braking done while cornering is minimal, you can probably scrub the same amount of speed with just the wheel that you can do trail braking, but trail braking keeps the front tires loaded nicely.

Vettel's brake pump is something i used to do on hairpins while simracing (not quite like that), gives you a good front bite when late apexing.

[xcutionr13]

Watch Hamilton's foot

[youtube]http://www.youtube.com/watch?v=ZKntP2V3djQ[/youtube]


Another interesting one. Look at 0:26 and 0:38

[youtube]http://www.youtube.com/watch?v=YKk7oeUhwdg[/youtube]

[raymondu999]

I think he's just locking his brakes in the first one to be honest - needing him to pump the pedal. It could be because I haven't had my coffee this morning, but I can't pick out anything special at 0:26 and 0:38 in the second video. What was it you were trying to show us?

As an aside - the video reminds me - do you trail brake in karts?

[Joie de vivre]

depends on what type of kart it is. but you also have to consider driving tecnique of driving gokart differs a lot from driving a formula 1 car. there is less trail braking in gokarting in general ... the trail braking is applied when you are entering the corner too fast.

[tathan]

Braking would just mean that you're using less and less of the lateral grip when you're not increasing the demand for lateral, no?

But braking would change load transfer big time. So the conditions you stated won't hold.

it's not just load transfer (which with an F1 CoG so low will be comparatively low), but the total available grip will change massively as you shed speed and aerodynamic grip approaches zero. This is why you might see them (counter-intuitively) using less and less lateral grip - it simply isn't there anymore.

[raymondu999]

Braking would just mean that you're using less and less of the lateral grip when you're not increasing the demand for lateral, no?

But braking would change load transfer big time. So the conditions you stated won't hold.

it's not just load transfer (which with an F1 CoG so low will be comparatively low), but the total available grip will change massively as you shed speed and aerodynamic grip approaches zero. This is why you might see them (counter-intuitively) using less and less lateral grip - it simply isn't there anymore.

If you read the context of my question though - we're talking about a constant radius corner, without a tighter corner approaching (think turns 1-3 in Shanghai). If you entered that corner at a speed already, and your trajectory can (geometrically speaking) take you to the apex and exit - why would you want to brake at all?

[tathan]

Hmm I see your point but even in a constant radius corner the path the car travels won't describe a circular arc, it will be more parabolic with a definite apex and hence a speed that decreases to a point then instantly increases again. There aren't many corners where there's a long wait before getting on throttle, I'm struggling to think of one. 1-3 at Shanghai is definitely tightening and the speed is dropping all the way around it, albeit maybe without actually braking.

[Jersey Tom]

Hmm I see your point but even in a constant radius corner the path the car travels won't describe a circular arc

Then it wouldn't be a constant radius corner now would it.

[tathan]

Hmm I see your point but even in a constant radius corner the path the car travels won't describe a circular arc

Then it wouldn't be a constant radius corner now would it.

Well clearly, but I was assuming they meant a constant radius corner in plan view because the example isn't and my memory can't think of one

[raymondu999]

If you reread my post - I used Shanghai T1/2 as an example of what we're NOT talking about.

[Mashed]

Trail braking is a simple technique to get the rear end of the vehicle to rotate for the corner. For obvious reasons, it transfers more weight to the front of the car thus making the rear of the car light and easy to rotate before turning in for the corner. Hope that makes sense. Basically the technique is used with cars that tend to understeer and/or on real sharp corners.

[raymondu999]

Trail braking is a simple technique to get the rear end of the vehicle to rotate for the corner. For obvious reasons, it transfers more weight to the front of the car thus making the rear of the car light and easy to rotate before turning in for the corner. Hope that makes sense. Basically the technique is used with cars that tend to understeer and/or on real sharp corners.

A bit late to the party I see