NGT Sprint Cup - Season 1, Round 4, Brno - Aug 2nd

[Simon Gymer]

I'm not sure that rear bias and late braking is that important. I run about 55 on the bias, but as an experiment I put it forward to 60 and tried to do a lap without late, heavy braking and without any significant trail braking in fact in some of the twisty bits I just didn't brake but lifted instead. The result was far from perfect (not braking meant I slid wide at one point, which must have cost a few tenths) but still quite competitive - 2.02.0.

http://homepage.ntlworld.com/paul.harrington/Brno%20Light%20Brake%202020.Vcr

You can see some corners where the brake lights are on part way after turn in, but this is more a case of trying to come off the brakes smoothly rather than any overt

I shall have a look at your replay as I was watching you online and you were jerking all over the place on the garage monitor so it wasn't easy to see properly. If i suddenly go quicker at brno you shall know why!

[fozzmeister]

I watched Paul in qualifying and he uses a hell of a lot of curb, brakes exceedingly late getting the back end ever so slightly out (I expect you're running a more than normal rear brake bias Paul? most of the really fast drivers usually do) enough to point the car in a better direction for the exit. It looked on the ragged edge to me which is probably why I can never be that fast as I'm quite a smooth driver. Hey if you can do it that's how to drive really fast.

If you've ever seen any of the real aliens of GPL you'll know what I mean by the whole rear brake bias thing and a sort of style that is really hard to master.

It's not a style most people can drive as you'll often end up spinning it a lot and you do have to tone it back a certain degree for racing over qualifying otherwise you risk losing it too easily.

This i don't understand at all, I quite well understand trail braking etc (or at least i thought), but my interpretation is that as your braking your using the weight at the front of the car to spin the rear of the car around the corner slightly. how would having a lot of rear brake bias help this process? The only way I can see would be to lock the rear wheels but surely that would be super dangerous. Unless you mean bringing it foward to the front.

Foz

[Paul968]

When you use the brakes, you use up a proportion of the grip available for each tyre. The traction circle principle says that a tyre has a limited amount of grip for both (plotted as a rough circle on a graph, hence the name), and the more you use for braking, the less is available for cornering. If you move the brake bias back and also trail brake, then the rear tyres are braking more and hence have less turning grip, the upshot of which being that the car has more oversteer/ less understeer than if the brake bias was more forwards.

hope that explains it.

Paul

[fozzmeister]

When you use the brakes, you use up a proportion of the grip available for each tyre. The traction circle principle says that a tyre has a limited amount of grip for both (plotted as a rough circle on a graph, hence the name), and the more you use for braking, the less is available for cornering. If you move the brake bias back and also trail brake, then the rear tyres are braking more and hence have less turning grip, the upshot of which being that the car has more oversteer/ less understeer than if the brake bias was more forwards.

hope that explains it.

Paul

Thanks Paul, I always have mine as far back as possible before rear brake locking starts happening, just for the reason of better braking. I've always concentrated more on the GPL style rear wheels slide with front wheels go round the corner thing, I take it that's the friction/traction circle too but in a slightly different way.

Fozzmeister

[Simon Gymer]

Interesting. Watched your replay Paul. It's not at all how I saw you drive in Q online. Maybe I didn't get a representative lap when i watched you in Q although you did set a reasonable time on the lap i watched.

Looking at the replay that's very much how I drive the lap, there was one place I noticed you take a bit of a different line, much tighter and across the curb so I might try that, but other than that it was very similar. I wonder if Pirellis are better at Brno on the F360s as I drive the Dunlop shod F360. I generally hate the Pirellis though as they feel more like they either have grip or they don't and nothing inbetween. When they let go they let go big.

[Paul968]

I'd be very surprised if tyres explained it. I also think that line on its own doesn't tell the whole story. Carrying speed through the corners is the main thing once the line is right, and this is what I love about the 360 at Brno - the feeling of chucking it in, holding the car right on the limit into an apex and then getting on the power - luverley jubley!

[Aagramn]

Lol, I still remember how pleased I was with my first sub-two-minute lap around Brno in a GT car, scary people are getting close to that in NGTs.

[Paul968]

Btw, which replay are you talking about Simon- 2.00.4 or the light braking one?

[Simon Gymer]

Light braking one (which is still 0.5 faster than my PB). I'll look at the other one now.

I like Brno too, although I do find the races turn into a bit of a procession with qualifying sorting out the race finishing order.

[Simon Gymer]

Hmm, watched your fast one now.

You're braking a lot later into most turns and on more of the tight corners you taking a large amount of inside curb, more than i'd dare to I reckon. I'm suprised that lap is as quick as it doesn't look like a great lap, but they are usually the ones that are I guess.

[PaulW]

Actually, that's what I thought! I followed Paul for a few laps during the practice session at Brno and thought you were taking an odd line at turn 1. Coming over fairly sharpish to what looked like an early apex, locking the right front up each time. But I can see what you were doing now and, boy, did it work for you!

I'm going to have to look at this trail braking malarky. I've been trying to smooth things out lately by not jabbing at the throttle at the exit of corners and trail braking (though I didn't know it) into big fast corners (T1 @ Brno a prime example) but it seems it's something I could develop for most corners that would let me brake a little later and hopefully corner a little better. Back to the drawing board!

[Rob Bywater "Kerb Crawlers"]

Could someone please explain in simple laymans terms what trail braking is, and the method of using it.

Cheers

Rob

[popabawa]

Rob, shamelessly nicked from another website; 

What is trail braking? In essence, it means continuing to brake after having turned in for a corner. The further you progress into the corner, the more you turn the steering wheel and the more pressure you release from the brake pedal. Typically, the procedure goes like this:

You are hurtling in a straight line toward a corner;

• You apply the brakes - fully - while still traveling in a straight line;
• At some point, you release a little pressure from the brakes and start to turn in;
• As you bend into the corner and approach the throttle application point, you progressively release the rest of the pressure from the brake

I *think* as you progress in GTR, you start to do it (if only a little) almost naturally as you explore the boundaries of the car/track. However, at some point, to get REALLY fast it has to become a concious effort to develop that skill as witnessed by Paul's amazing replays.

I'm sure someone who knows what they are talking about can add a bit more!

[Dave 'Gizmo' Gymer]

Could someone please explain in simple laymans terms what trail braking is, and the method of using it.

Here is quite a good explanation, but in essence you use a little brake pressure to keep some weight transfer on the front wheels during turn in to aid front grip. I found myself doing it quite a lot at Castle Combe in the wet to prevent understeer. I actually find it much easier to do in real life because you can feel the weight moving about.

[Rob Bywater "Kerb Crawlers"]

Thanks guys   

Cheers

Rob