Does ABS set to "0" means understeering hell

[newbielives]

I've been racing untuned settings on FR cars with the G25 for a while now and thought I was just starting to get the hang of it. Finally I decided to play with the tune settings and set ABS to "0" and WOW talk about understeering durring braking. It feels like in every corner I have to brake heal toe downshift, then brake and gas at the same time to regain grip. Now I could resort to braking only in a straight line but that just seems slow compared to my old way of driving where you mostly brake in a straight line then jab on the brakes here and there to correct what is needed. With ABS set to "0" it's like jab brake, and prepare for understeer hell.

Not complaining about the physics, actually more interested on what TIPS the Pros on here have regarding driving with ABS set to "0" and still matching your regular stock times where ABS is set to "1"

 

[Earth]

Maybe you could be locking up the tires and losing traction thats why it understeers

 

[GTP_chemicaL]

Have you tried lowering front brake pressure.

 

[newbielives]

Maybe you could be locking up the tires and losing traction thats why it understeers

That might just be it as I'm usually jabbing the brakes full on durring braking.

Have you tried lowering front brake pressure.

I'm going to try this too as I'm not fan of the Forza2 feather feet style of braking

 

[Threshold]

You feel understeer it's because the tires lock up and the car begins to slide. The law of physics state that an object that's moving in one direction will want to keep moving in that direction. The tires are the only thing that make it possible for cars to go in curved lines. Once they lose grip the car will revert to it's natural tendency to move in a straight line. Which all translates to understeer.

ABS means Anti-lock Braking System. Computer sensors in each wheel sense when one wheel has stopped rolling and has locked. It will compare this data to the signal coming from the other 3 sensors, and if those 3 sensors tell it that their wheels are rolling just fine, then the computer will, through the ABS pump and valve box, reduced the amount of pressure the brake fluid exerts on the caliper of the wheel that is locked. That will cause the locked wheel to beging rolling again, giving back the driver control. ABS maximizes your stopping power at each individual tire. With ABS off I don't think you'll ever match your times with ABS on. You'll need 4 brake pedals to do that.

So with no ABS, you the driver have to prevent the tires from locking up. To do this you basically have to feather the brake pedal, but if you feather it too much you're not achieving maximum braking potential. Optimally you should brake to the point to just before the tires start to lock up. It's very tricky though, because if you're braking in a straight line and you're just at the edge of tire lock up, and you try to turn the car even the slightest you would immediately get tire lock up. That's because all of the grip that the tires have available is being used for stopping the car, and if you ask them to turn the car as well they will just run out of grip. The trick is to lift of the brake as you turn the car. This gives the tires some grip to get you around the turn. This is called Threshold Braking (same as my name tag). But don't lift too much or turn in enough, or you won't be using the tires to their maximum potential, which will cost you time.

 

[Scaff]

That might just be it as I'm usually jabbing the brakes full on durring braking.


I'm going to try this too as I'm not fan of the Forza2 feather feet style of braking

You are in this case most certainly locking the fronts up under braking, which results in a massive loss of grip at the front end and as a result a huge amount of understeer.

With ABS switched off you need to be far more aware exactly how you have your brakes set-up, in terms of the level of brake force applied and the bias itself. To a degree you will always have to be aware of the degree of pressure you apply to the brake pedal with ABS set to zero, particularly at lower speed when its easier to lock the tyres.

Regards

Scaff

 

[nissan tuner]

stop flooring the brake pedal and this wont happen to you. braking & turning is another thing to avoid

 

[newbielives]

Thanks for the tips and the explanations (1up to Threshold), even the video by nissan tuner is quite remincent of my braking lock ups lol

 

[Stotty]

The braking in gt5p with abs off is totally unrealistic... in both my road cars (civic & 911) you can brake extremely hard and deep in to corners without trggering the abs - though you have to be a little more careful in the porsche or the rear end gets a bit loose.

 

[Earth]

The braking in gt5p with abs off is totally unrealistic... in both my road cars (civic & 911) you can brake extremely hard and deep in to corners without trggering the abs - though you have to be a little more careful in the porsche or the rear end gets a bit loose.

That's exactly why I don't turn off ABS in GT5P, it needs alot more tweaking from PD.

The brakes lock up way too easy even on some lower powered cars even at 100+ mph

 

[Chadwicksracing]

The braking in gt5p with abs off is totally unrealistic... in both my road cars (civic & 911) you can brake extremely hard and deep in to corners without trggering the abs - though you have to be a little more careful in the porsche or the rear end gets a bit loose.

That's exactly why I don't turn off ABS in GT5P, it needs alot more tweaking from PD.

The brakes lock up way too easy even on some lower powered cars even at 100+ mph

This is also why I don't use it.. I never thought a car could lock them up with only 30-40% applied. lol PD has a bunch of work to do.

 

[Biggles]

GTP_CWR> That stupid took us THREE WIDE Bigglies

It's not "Bigglies" it's "Biggles"

http://en.wikipedia.org/wiki/Biggles

 

[panjandrum]

That's exactly why I don't turn off ABS in GT5P, it needs alot more tweaking from PD.

The brakes lock up way too easy even on some lower powered cars even at 100+ mph

I agree 100%. I don't know who is testing these things at PD, but brake, throttle and clutch sensitivity is all completely off with my G25. Throttle and Brakes aren't any better with my DFP. I use ABS=1 and things seem OK that way.

I've long suspected that what we may be seeing here is a very Japanese attitude toward car handling. You'll notice that pretty much all the great handling cars out of Japan handle great because of their computers. This is something that Europeans and Americans generally don't like and, to be blunt, almost consider "cheating." My suspicion is that if you were to go to PD and look at the settings the PD staff use for their setups, they would be using TCS and ABS all over the place. I expect if you looked at their GT4 "tunings" you would see them using the Oversteer and Understeer settings all the time also. But most of use GTP-ers don't like using those controls, we set them all to "0" wherever possible, and I think the people designing these games fundamentally don't understand our viewpoint on this subject. (And, we don't understand theirs.) That is, my guess is that when they encounter funky handling or too-sensitive brakes, they simply change settings that most of us here would prefer not to even use.

 

[Scaff]

That's exactly why I don't turn off ABS in GT5P, it needs alot more tweaking from PD.

The brakes lock up way too easy even on some lower powered cars even at 100+ mph

What has the power of a car got to do with its braking ability and the likelihood of it locking up?

Guys you need to keep in mind that as soon as you turn off ABS then you have no 'safety-net' from the default settings of the brake bias. Given that its set to 5/5 as a default you can't hope to get even close to a realistic feel without some adjustments.

While GT5P does still need some work, once you set the brake bias and force levels to a more realistic level its actually not as fair out as you guys are suggesting.

The biggest culprit is the equal bias that is given as a default, this is something you would never come across in the real world, load shift forward under braking and cars need a front bias to braking. Simply changing most cars to a starting point of 3to4 at the front and 1 at the rear makes a massive difference (and is a lot more realistic in terms of a bias set-up).


Regards

Scaff

 

[Suzuki]

Yes Scaff! That is what I was about to comment on. Once you take ABS to 0, it will set the bias to 5/5. Most factory cars would be more like 4-3/2-1 front/rear. Having a high brake bias will make it a LOT easier to lock the tires up under braking. I wouldnt reccomend going over 5 or 6 period. It just gets too touchy after that.

 

[panjandrum]

The biggest culprit is the equal bias that is given as a default, this is something you would never come across in the real world, load shift forward under braking and cars need a front bias to braking. Simply changing most cars to a starting point of 3to4 at the front and 1 at the rear makes a massive difference (and is a lot more realistic in terms of a bias set-up).


Regards

Scaff

OK, I'll give it a try. End the end, when discussing GT4/5 physics, it is important to remember this one important rule: Scaff is always, always right!

I never even gave a thought to the possibility that the default brake bias wouldn't be and appropriate default setting to start working with.

 

[Scaff]

OK, I'll give it a try. End the end, when discussing physics, it is important to remember this one important rule: Scaff is always, always right!

I never even gave a thought to the possibility that the default brake bias wouldn't be and appropriate default setting to start working with.

👍

With the default set-ups on GT5 (and just about any GT) the two settings that are almost always wrong on the default are Brake Bias (equal front and rear is just plain wrong and almost always set too high) and dampers (again equal and too high).

They are always the two areas I tend to look at first when tuning for that reason.

If you want a fun but silly setting to try, which does show that brake bias settings have got a lot more important in GT5, set the brake bias to 10 at the rear and 1 (or 0) are the front and turn the ABS off. Now try and get a lap in without spinning; the massive level of force at the rear with a total rear bias just locks the back end up when you so much as breath on the brake pedal (rear lock up = massive instability in a car). You could do this on GT1 through to GT4 and because we could not turn off the ABS all it would do was increase braking distances.

It does also starkly illustrate just how much of a difference turning off the ABS now makes to the importance of brake bias.

Regards

Scaff


Oh - and let me know how you guys get on with a tweaked brake bias, I find that it makes a huge difference.

 

[mindwise]

.... 5/5 as a default

. Simply changing most cars to a starting point of 3to4 at the front and 1 at the rear makes a massive difference (and is a lot more realistic in terms of a bias set-up)...

Regards,

Scaff

To add on that, or maybe just to clarify myself, if wrong please correct:

Newbielives, i hope i'm right when i write that Scaff's suggested settings are optional for maximum braking, not particlularly taylored for minimum understeer while braking.
For maximally reducing understeer using brake bias i "suggest" 👎 1/10 👎

My brake bias indeed is more to the front then to the rear for reasons found in Scaff's guides linked ^^^^.

but i find it quite tricky to drive with ABS on 0 Newbielives, you may just have inspired me to give it another hour of trying

Scaff, or anyone, what do you make of the braking while cornering? too forgiving?

 

[Chadwicksracing]

It's not "Bigglies" it's "Biggles"

http://en.wikipedia.org/wiki/Biggles

ITs my nickname for you..bigglies.. lol I guess I will just have to use your orginal name.

 

[StrikeEagle737]

To add on that, or maybe just to clarify myself, if wrong please correct:

Newbielives, i hope i'm right when i write that Scaff's suggested settings are optional for maximum braking, not particlularly taylored for minimum understeer while braking.
For maximally reducing understeer using brake bias i "suggest" 👎 1/10 👎

My brake bias indeed is more to the front then to the rear for reasons found in Scaff's guides linked ^^^^.

but i find it quite tricky to drive with ABS on 0 Newbielives, you may just have inspired me to give it another hour of trying

Scaff, or anyone, what do you make of the braking while cornering? too forgiving?

Sometimes, it does seem a little forgiving except in the Nissan GT-R R35. In that car, if I try to brake while turning, my rear end will swing loose.

Also, thanks Scaff for the brake bias advice. I never noticed that the 5/5 bias was unrealistic. Although, I usually set ABS to 2, so I don't have a problem with locking wheels.

 

[Earth]

What has the power of a car got to do with its braking ability and the likelihood of it locking up?

Brake size

I doubt the itty bitty brakes on slower cars will get even close to locking up when clamped on at 100+ miles per hour

 

[Threshold]

Brake size

I doubt the itty bitty brakes on slower cars will get even close to locking up when clamped on at 100+ miles per hour

Race brake pads will lock up the brakes quicker too.

 

[Scaff]

Brake size

I doubt the itty bitty brakes on slower cars will get even close to locking up when clamped on at 100+ miles per hour

First you are making the assumption that 'sportier' cars automatically have better braking systems (or even ones that are spec'd to the needs of the car), its not always true. BMW's M division cars have been criticised by many road testers over the years for poor brake feel and being prone to fade under hard use.

You are make the mistake of linking the speed you need to slow from as the only factor involved in determining the size of disc required, yes speed is a factor (as we are looking at Force = Mass x Acceleration here, with the force part being the Force required to start slowing the rotation of the wheel) but the vehicles mass is also a factor in determining disc and pad specification. A Caterham weighing in at under 400kilos does not need huge pads and discs to effectively brake, while a 1,500kilo car with much bigger discs may struggle to be as effective.

Actually pretty much any modern working brake system will lock up tyres in a single incidence, bigger brakes and better pad materials generally only give you major advantages in terms of reduced brake fade, improved feel and modulation.

Pads and discs don't stop a car, they simply slow the rotation of the tyre, its the tyre itself that stops the car and is the principal factor in determining lock-up and stopping distances.

Lock- up at 100+ mph is actually less likely than lock-up at 20mph (regardless of the braking system), lock-up occurs when the tyres exceed the slip percentage. Which is the difference between the rotational speed of the tyre and the speed the car is travelling at. To illustrate say a tyre has a slip percentage of 10%, at 100mph you would need a difference of 10mph before lock-up would occur, at 30mph you would need a difference of 3mph. Hence the reason you are more likely to lock-up in slower corners than quicker ones (Note - While the above is true the real physics involved are a lot more complex - particularly if cars that generate true downforce are looked at - that's a whole other ball game - but we are talking road cars here).

That aside, in a single stopping incidence almost any well maintained and functioning brake system is going to be able to lock tyres up; the difference is weither the will be able to then keep working effectively for full threshold braking, lap after lap after lap. That's the advantage of bigger discs and pads.

Have a read of this thread, which goes into these topics in a lot (and I do mean a lot) of detail.

GT4 & Brakes

And these are worth a read as well
The physics of braking
Brake Bias and why it matters

Taken from that second article...

Long, long ago in a magazine far, far away, a few renegade brake engineers rallied together to bring forward the following message:

“You can take this one to the bank. Regardless of your huge rotor diameter, brake pedal ratio, magic brake pad material, or number of pistons in your calipers, your maximum deceleration is limited every time by the tire to road interface. That is the point of this whole article. Your brakes do not stop your car. Your tires do stop the car. So while changes to different parts of the brake system may affect certain characteristics or traits of the system behavior, using stickier tires is ultimately the only sure-fire method of decreasing stopping distances.”

Yes bigger pads and discs (as long as the rest of the braking system is also upgraded) can exert more braking force, but as even road car systems are capable of exerting enough force to lock tyres up (they just will not be able to do so repeatedly), haveing even more force will not make a jot of difference here.


Simple bullet point rules for braking.

1. Stickier tyres is the only way to ensure shorter stopping distances.

2. Good brake bias settings maximise those stopping distances (but can't reduce them)

3. Bigger pads and discs don't stop you quicker, but they do give you more control and less fade.


Regards

Scaff