PDA

View Full Version : Help with brake balance



STaLLiOnO
24-02-2018, 17:07
I'm runing the Mercedes Touring Car, plus GT3 Car. My ABS is on 70%. I need help with the brakes. The brakes keep locking up. I need a good setting. Help is appropriated

blinkngone
24-02-2018, 17:34
Hi STaLLiOnO, this screenshot is of a SLS GT3 setup but most of the time your brake locking can be controlled by reducing the Brake pressure and moving the Brake Balance forward.
250628

cpcdem
24-02-2018, 22:42
I have raced a few times with this car, as in all touring cars, the default brake bias is way too much to the front (at least for the way brake bias is modeled in the game). Turn it a lot to the rear, at around 45-55 and you should be fine with locking (it's always the fronts that lock in the default setting).

blinkngone
25-02-2018, 00:30
This is Tiki's AMG A 45 SMS-R Touring, Monza GP brake setup. Not much of a surprise with TT setup sharing but Fe1ixS's brake setup at #2 is the same. I guess the brake setup could be track dependent.
250647
RBR GP TT WR brake setup.
250648

hkraft300
25-02-2018, 00:42
Turn it a lot to the rear, at around 45-55 and you should be fine with locking

For the Mercedes GT3 cars you want ~62% front bias for minimal locking.
Also if your pressure is at 100% and you always stomp the brakes, you'll lock them regardless of bias settings.

It's called threshold braking. Try it.

cpcdem
25-02-2018, 01:36
For the Mercedes GT3 cars you want ~62% front bias for minimal locking.
Also if your pressure is at 100% and you always stomp the brakes, you'll lock them regardless of bias settings.

It's called threshold braking. Try it.

Thank you very much, I will! I was referring to the TC Mercedes though.

blinkngone
25-02-2018, 02:00
Hi cpcdem, I think you mean the AMG A 45 SMS-R Touring, that is the only Merc Touring car I could find. Most of the people are running the forward brake balance with this car, they don't have the same abilities as you do so that is why they are running with forward balance in TT, that's the only setups I can look at. I was able to find some runs with the 52/48 you suggested at Silverstone National, Laguna Seca and Nurburgring GP but the OP didn't mention which tracks he was having problems with so I just picked the more popular ones like Monza and RBR where the balance was 60+ toward the front on most cars at the top of the Leaderboard. Even SEL at Brands Hatch GP is running 60/40 with this car.

STaLLiOnO
25-02-2018, 02:22
Thanks for the responses guys. The brake ducts are just as important as well. Trying to see how much, i can get away with them slightly open.

cpcdem
25-02-2018, 03:33
Hi cpcdem, I think you mean the AMG A 45 SMS-R Touring, that is the only Merc Touring car I could find. Most of the people are running the forward brake balance with this car, they don't have the same abilities as you do so that is why they are running with forward balance in TT, that's the only setups I can look at. I was able to find some runs with the 52/48 you suggested at Silverstone National, Laguna Seca and Nurburgring GP but the OP didn't mention which tracks he was having problems with so I just picked the more popular ones like Monza and RBR where the balance was 60+ toward the front on most cars at the top of the Leaderboard. Even SEL at Brands Hatch GP is running 60/40 with this car.

I figured it out, 52-48 is the setting in the default loose setup, while 60-40 is the stable setup setting, so it does indeed make sense.

It's not difficult to drive those cars with a more rear bias, they do not oversteer while braking unless you really overdo it with the bias, so it's not that I have more skill to handle it. But then again, as always you are right, I just checked the car in RBR and even with 60-40, it doesn't really lock the fronts much..not sure why I was experiencing the other day heavy front locking (and had to put the bias much to the back), maybe it was due to the different track and/or weather conditions.

Jussi Karjalainen
25-02-2018, 04:06
I figured it out, 52-48 is the setting in the default loose setup, while 60-40 is the stable setup setting, so it does indeed make sense.

It's not difficult to drive those cars with a more rear bias, they do not oversteer while braking unless you really overdo it with the bias, so it's not that I have more skill to handle it. But then again, as always you are right, I just checked the car in RBR and even with 60-40, it doesn't really lock the fronts much..not sure why I was experiencing the other day heavy front locking (and had to put the bias much to the back), maybe it was due to the different track and/or weather conditions.EDIT: Hah! I thought RBR meant "Richard Burns Rally" hehe. I'll leave that part in anyway since I find it amusing enough. =)

Original post: While I'm not 100% sure how RBR handles their brake bias, there's a good chance that they're showing the "effective" brake bias. Think of it as both front and rear brakes being equally powerful, and the brake bias showing what the actual braking power distribution will be.

We handle it a tad differently, arguably more realistically, in that all cars have front and rear brakes set up individually. On some cars the might be the same if they're like that in real life, but for the vast majority the front brakes are a lot beefier than the rear brakes. Taking the Mercedes-Benz SLS AMG GT3 as an example, the front brakes on it are so much more powerful, that even when you set the brake bias to 50:50 it'll still be about 65:35 in practice due to difference in how powerful the brakes are. IRL the brake bias adjustment tunes the literal brake fluid pressure distribution in the braking system, so if your foot pressing down on the brake pedal causes a 5 bar pressure to be generated, a 60:40 pressure distribution will send 3 bar to the front and 2 bar to the rear (5*0.6=3). This is what the brake bias setting in our setup models as well, and the actual differences in the brakes add their own effect on top of that.

As to why cars generally run more front brake bias, or at least have stronger front brakes? Partially it's because at least in RWD cars the engine braking is increasing the braking force at the rear, at least if you shift down aggressively, but mostly it's simply because when you brake, the load transfers forwards heavily, meaning front tyres get more grip while rears lose grip. For the majority of cars a true 50:50 brake force distribution would be insanely oversteery, the rears locking up way too soon. Even the FWD racing cars in this discussion, with their brake bias often in the 45:55 region, are still effectively front biased, because the natural brake bias of the brakes is about 76:24 to the front. This makes sense really, since the vast majority of the weight of the car is on the front tyres at all times, and even more so when braking (we're talking 60/40 weight distribution when standing still and a load distribution of around 80/20 front/rear when braking hard!). If you tried to make front and rear brakes anywhere near equal the rears would be locking up constantly. And since you don't need as much brake performance at the rear, you can make the brakes smaller and lighter, improving unsprung mass and reducing overall weight.

And one final quick note, something for you to possibly try to take advantage off: Fuel tanks are usually towards the rear of the car, and move the weight distribution rearwards, increasing load and grip on the rear tyres. So when you're starting a race with a full tank of fuel, you might be able to run the brake bias more towards the rear for improved braking performance without sacrificing stability, and move it slowly forwards as you run lower and lower on fuel. =)

cpcdem
25-02-2018, 13:11
Thanks a lot for the info and also thanks for leaving there the original part about the "other" RBR! :)

One more question if I may: With GT3 cars, change the brake bias even just a bit, for example to the 488, from 54-46 to 50-50, it makes such a big difference, in some tracks I am using 50 in some corners, 54 in some others, 52 in the rest and I like it that this helps. In the touring cars though, such small changes have very little impact, you have to be very aggressive with that to notice the difference. For example in the Renault I am using 45-55 instead of the default 58-42 (IIRC), in the BMW had to use 40-60 to get a better turn in.

Unfortunately I have absolutely zero experience with RL racing and setup of race cars, but I am wondering if this is how it should be. And for me it's not a problem if it is not modelled completely realistically in the game, it's way too much to ask from our personal computers to create a 100% realistic simulation of what happens in real life, just wondering about that, though.

Jussi Karjalainen
25-02-2018, 13:27
I think it's probably just because the rear brakes on the TCR cars are so puny compared to GT3 cars (which enjoy a much higher downforce as well as a much more rear heavy weight distribution), small changes don't have that much of an effect.