GCS Driver Training advice on break bias testing

[Rick Malm]

Can you advise me on the best way to test brake bias?

I know the theory of what it does.

But how does one compare its effectiveness as you learn about it?

A skidpad would be nice to measure bias vs shorter braking distance required to get the desired speed delta in a straight line or measure control of speed reduction while turning. I understand concept, but how to determine amounts other that trial and error lap after lap.

I did read some good posts when to use brake bias http://www.racedepartment.com/forum/threads/breaking-bias.61215/#post-1318663

 

[Troy Barman]

Here is the skidpad track Neils used that i converted with grumbel's tool. Just drop the Locations folder into your Gamedata folder and let it overwrite.
http://www.mediafire.com/download/pdo8vskruiuj27w/Locations.zip

 

[Rick Malm]

Thanks so much. I will install tonight.

 

[Rick Malm]

Opps, your Location.zip is invalid or empty. I redownloaded and same error.
Tried 2 unzip utilities.

 

[Troy Barman]

Opps, your Location.zip is invalid or empty. I redownloaded and same error.
Tried 2 unzip utilities.

I just downloaded it and didnt have a problem with it. I dont know what the issue could be.

 

[Ho3n3r]

If you lock up the rears under braking, move it forwards as little as you can until it doesn't throw the back out under braking any more.

If the fronts lock up too easily, move it backwards more and more.

Ideal is 50/50, but that is not possible in a good mod. So you have to basically get as close to 50/50 as possible without locking up the rears, which is easy to notice because your car's rear end comes around under braking.

 

[Rick Malm]

I just downloaded it and didnt have a problem with it. I dont know what the issue could be.

Tried on a 2nd cpu running XP and same error. invalid, corrupt, or empty.

What did you use to zip it?

It cleary has some data in it since the size shows 88kb.

I will tried on a 3rd cpu a w7 OS, same problem. I am stuck as well.

 

[Rick Malm]

If you lock up the rears under braking, move it forwards as little as you can until it doesn't throw the back out under braking any more.

If the fronts lock up too easily, move it backwards more and more.

Ideal is 50/50, but that is not possible in a good mod. So you have to basically get as close to 50/50 as possible without locking up the rears, which is easy to notice because your car's rear end comes around under braking.

I have a case right now where front right locks with F68 R 32.. Will try your ideas. Thanks

 

[Rick Malm]

I just downloaded it and didnt have a problem with it. I dont know what the issue could be.

Got it. Looks like the downloader was failing to finish correctly The key was the size of the file I got was too small. I have it all now and unzipped, installed and it work. Great, just what I needed some measured circles.

 

[Ho3n3r]

I have a case right now where front right locks with F68 R 32.. Will try your ideas. Thanks

You do have buttons assigned to adjust the brake balance forward/backward during driving, right? So you don't have to go into the pits every lap to adjust it. You can even test it corner by corner.

 

[Rick Malm]

Well on m F1 wheel I put bias on the 2 buttons on the right side, button B6 and B12, but did not see any response from pressing them. I see that are set in the options control controller1 and I see them in the controller.ini but nothing. SO is create a new profile and started over with a new PLR and I can see the bias. I am in business now. One must be careful with PLR edits, lots of vars that are not defined anywhere.

 

[Tim Ling]

@rickmalm The inside front may lock up as you turn in because the weight on it is unloaded

 

[Rick Malm]

Good point. Should I change tire pressure in it, change bias, or just quite pushing so hard on the brakes.

 

[Tim Ling]

From everything I've read, you're supposed to get your braking done in a straight line. Trail braking (braking into the corner) is a difficult skill to master, and practice is the only to get it right.

 

[Rick Malm]

Right now my brake area is all straight. I was 1st taught this at Bondurant. I have not really practiced trail braking in GSC yet as you can see by my MoTeC plots on other posts. I did try it when I started running GSC a month ago but the laps times dropped 2 to 3 seconds when I stopped doing it and focused on getting off the brakes and throttle and put all the tire friction into making a good turn into the apex vs sliding wide.

I tried the skidpad with braking bias. Could not get stopped much earlier and notice as it move to the rear keeping straight is really important as you tend to loose the rear and start to spin.
Some day I will try skidpad testing with different wing setting, and pressure settings given same speed when braking starts. For now I will try to stop the R front lockup with just less braking force and try to adjust on time to keep speed up in the corner. In the past, I jam on the brakes full and just vary the time that they are full down based on the corner radius since that technique is simple to get the feel good and you get quick feedback if its too much or too little. Trail braking should keep the fronts weight down and allow some later control with practice.

 

[Niels_at_home]

The optimal balance isn't often 50/50. When braking there is weight transfer to the front, front tires are heavy loaded, rear tires less heavy. The available brake grip is related to the download on the tires, so the heavier the tire is loaded, the more braking grip it can provide. The *actual* bias that you get, i.e. the braking applied by the front vs rear tire contact patch depends further on the tire radius, brake disc/pad 'effectiveness' and when the engine is connected, you get some engine braking on the rear axle as well.

Sounds (and is) all pretty complex. Also, the better you become at braking, the harder you brake, the more weight transfer forward and the more forward your brake bias has to be to stop initial rear tire locking.

If you start pretty far rearwards you notice soon enough when that is too much as you will soon face the wrong way.. Then move it forward until this effect no longer happens and ideally you feel the car slide on 4 wheels a little bit before any tires lock.

 

[Rick Malm]

Thanks for your tips Niels. I did check out your latest video on brake pressure math calculations. Off to the skidpad and try different bias. I dont think I can even get below 60/40 with the bias buttons in GSC. With any slight turn at 60/40 I will start to spin.