Threshold Braking doesn't seem to work in Prologue...

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Jack B
I started watching some replays of top times in Arcade Time Trials. I was checking braking zones, entry, mid and exit speeds etc. Of course I also looked at when they got on the throttle and how much. Same with braking.

The odd thing was that the top times didn't use any threshold braking. It was either 100% on or 100% off. So, I too my GTR and went to Suzuka and decided to do a braking test.

The first test was on the Arcade Time trial. I lined up at the red line under the 1st Suzuka overhead sign. My plan was to get as much speed as I could from a dead stop and brake at the start line to test ABS and threshold braking. I set the transmission to automatic to minimize human error. I couldn't see a difference in braking and attributed it to maybe being an "Arcade" thing.

So, I went to 700P Online Suzuka Time Trial and used the Quick Tune to Adjust ABS.

==========================

Test 1 - Slamming on my brakes with ABS set to zero.

Result - Lots of smoke and I typically stopped right about on the middle of the 4th section of seats.

=========================

Test 2 - I then tried threshold braking with ABS set to zero.

Result - After about 10 tries, I wasn't able to stop any quicker threshold braking as I could by slamming on my brakes and it was much less consistent. I over shot quite a few times. Much worse than just slamming on my brakes. Sad result.

============================

Test 3 - I then tried slamming on my brakes with ABS set to 10.

Result - I typically stopped in the same spot as without ABS, except without any smoke. Very strange. Maybe I got a 10 feet advantage. Maybe, but it was very very close. Still about the middle of the 4th section of the grandstands.

============================

Test 4 - I then tried threshold braking with ABS set to 10.

Result - Basically, the same as every other method. Same stopping distance just without the tire smoke and noise. Another sad result.

=============================

Conclusion:

Just slam your brakes on. Leave off ABS if you like to hear loud tire squeals and smoke, but otherwise you'll stop just as quick either way. Slamming brakes 100% wins. It's not about touch or feel or threshold braking. It's about timing. Hit your brake zone mark and hold until you hit your target speed then release. 100% to 0%. Not good.

===========================

Has anyone tried anything similar? Throttle oversteer works well, but the braking seems to be broken.

Maybe I did something wrong.

EDIT: I fixed my typo on test 2. I had ABS set to zero there as well.
 
The ABS at level 10 will essentially take care of the braking no matter how hard you stand on the brakes. If you want threshold braking, which is what I do as well, set ABS to 0. Be advised though, setting ABS to 0 will also eliminate the stability control. But I guess if you're already looking for that sense of realism, ASM will have been turned off long before. :)
 
Maybe I did something wrong.

You could say that.

Threshold braking with ABS enabled is pointless and not going to stop you any quicker at all. Judging it with ABS enabled is going to be rather pointless as even if you overstep on the braking the ABS will take over for you.

Try slamming on the brakes to lock up the tyres with ABS obviously set to zero and then threshold braking with the ABS again set to zero. That would be a better test of what is actually threshold braking.

Regards

Scaff
 
what car did you use for this test? i know im the vette if i slam the breaks thats the end of my race i might as well just give up at that point i have to be gentle on the breaks and i have ABS turned off
 
The ABS at level 10 will essentially take care of the braking no matter how hard you stand on the brakes. If you want threshold braking, which is what I do as well, set ABS to 0. Be advised though, setting ABS to 0 will also eliminate the stability control. But I guess if you're already looking for that sense of realism, ASM will have been turned off long before. :)

I had a typo. I did try with ABS set to zero. It didn't work. I used the Nissan GT-R '07. Try it for yourself.

You could say that.

Threshold braking with ABS enabled is pointless and not going to stop you any quicker at all. Judging it with ABS enabled is going to be rather pointless as even if you overstep on the braking the ABS will take over for you.

Try slamming on the brakes to lock up the tyres with ABS obviously set to zero and then threshold braking with the ABS again set to zero. That would be a better test of what is actually threshold braking.

Regards

Scaff

See my comment above. I tried both tests with ABS at zero and at 10. The results for all for tests were almost identical. Basically, ABS and threshold braking are broken.

I don't know exactly how much farther you should skid if you lock up your brakes at 120 mph vs perfect threshold braking, but it's a lot. It appears braking is either "ON" or "OFF". I'm disappointed. You should try it for yourself.

I think he did do that, he just had a typo and said it was threshold braking with ABS set to 10. (His 2nd point)

Thanks. Yes you are correct. I had a typo.

This is a pretty serious issue for a sim if it's true. I hope it isn't, but it was a pretty good first test. Maybe it's a bug in the GT-R. I could test some other cars or just look at a bunch of replays on different scoreboards. If the brakes go 100% on for the hard braking turns, then it's likely broken. 100% is not threshold braking.

If this is true, then braking is all about nailing your brake zone and then timing when to let off. It's almost like a rythym game. No feel all rythym timing for braking. That's not good. Hope it gets fixed for GT 5.

Wheel slip from acceleration feels ok. I wish we had a skid pad in the game though. Great way to test. :)
 
i really agree with this. I try to always squeez the brakes but nothing really comes out of it. The best way to slow the car is to slow the wheel not floor the breaks. or as we like to call it Threshold Braking ...maby we are doing something wrong here. PD should really look into this and atleast give an explanation
 
I just realized not everyone here may know what threshold braking is.

Here's the Wikipedia link. Click here.

Threshold braking or limit braking is a driving technique wherein the driver adjusts control of the brake system in an attempt to maximize the braking force of the vehicle. Done properly, this reduces the time and travel distance required to stop the vehicle to optimal amounts, or when racing, allows the driver to delay braking when entering a corner. The optimal amount of braking force is developed on a wheel at the point when the wheel just begins to slip (optimal slip will be between 5-15%). Braking beyond this point, as the tire begins to slide, the friction force between the tire and driving surface transitions from the static friction range into the kinetic friction range. Threshold braking avoids sliding and tries to keep the tire's percentage slip at the optimal value, the value that produces the maximum frictional force.

The friction force (i.e. braking force) developed between the tire and driving surface is proportional to the load on the tire times the coefficient of friction. The coefficient of friction is a complex combination of factors, the most important of which is the combination of materials involved, namely, the tire (usually rubber) and the surface (asphalt, dirt, ice). When the wheels are slipping significantly (kinetic friction) the coefficient of friction is typically substantially less than when the wheels are not slipping (static friction) thereby reducing the braking force. The peak coefficient of friction occurs between static and dynamic endpoints, at the optimal slip percentage. The coefficient of friction is also a function of temperature, humidity, and applied load.

Threshold braking is very difficult even for experienced drivers under controlled and idealized conditions. It is nearly impossible for most drivers to perform in the real world, especially when surprise, driver training and fitness, vehicle maintenance, and road and weather conditions are factored in, whether singly, or in combination.

Bottomline is that threshold breaking is using the precise amount of pressure to just keep the wheels from locking.

I bought this expensive Logitech G25 wheel and I'm pretty bummed out, that the brake pedal might as well be a button in Prologue. PD, please fix! :grumpy:

i really agree with this. I try to always squeez the brakes but nothing really comes out of it. The best way to slow the car is to slow the wheel not floor the breaks. or as we like to call it Threshold Braking ...maby we are doing something wrong here. PD should really look into this and atleast give an explanation

I think it's a bit like the rubberbanding/boost stuff with online. I don't think PD thought we'd notice.

I hate finding stuff like this out. It's like when your all excited for Xmas and then some bigger kid tells you Santa Claus is a fake. :crazy:

Update. I just watched el greco's 2:00 time on Suzuka. He used variable breaking on some turns, but 100% on others, so I need to take a closer look at more replay's. More tests! :)
 
Update. I just watched el greco's 2:00 time on Suzuka. He used variable breaking on some turns, but 100% on others, so I need to take a closer look at more replay's. More tests! :)

There's plenty of cornering in Suzuka where you're going to be on the throttle and brake. Depending on the driveline and engine mount, different rates need applied to each pedal through the turn to achieve the best speed through apex and exit... very positive simulation aspects.

100% braking only works in Pro physics when you're doing it in a straight line. Brake pressure management (especially with ABS off) is absolutely necessary the moment you get on the brakes when the car has lateral forces acting on it. Try going from 0-100% on the brakes while heading into turn one at Suzuka or Daytona Road. :)
 
There's plenty of cornering in Suzuka where you're going to be on the throttle and brake. Depending on the driveline and engine mount, different rates need applied to each pedal through the turn to achieve the best speed through apex and exit... very positive simulation aspects.

100% braking only works in Pro physics when you're doing it in a straight line. Brake pressure management (especially with ABS off) is absolutely necessary the moment you get on the brakes when the car has lateral forces acting on it. Try going from 0-100% on the brakes while heading into turn one at Suzuka or Daytona Road. :)

I use trail braking quite a bit, but that's not what I'm talking about. I've done trail braking and it does bleed off speed, but that's not what I'm talking about.

Try my tests yourself. See if you can stop in a straight line faster with threshold braking or just slamming on the brakes. Unfortunately, in my tests slamming on the brakes worked better even without ABS.

I'm not sure how much farther you should skid once you lock up the brakes, but it's got to be at least 50% further. That's the reason you see people skidding into rear enders. They've locked up the brakes. If slamming on the brakes 100% in a straight line without ABS doesn't lock up the brakes then what will?

My tests could be off, but your comments don't change my opinion at this point. Maybe Professional Physics behaves differently in Time Trials than it does in Career Mode or Online. I don't know, I didn't build Prologue. There are some quirks, but for my tests ABS didn't seem to do anything. It doesn't make sense to me, but that's what I found. Do you own tests.
 
Has threshold braking worked in previous GT games. I don't get it, why even have ABS options if it doesn't make any difference?

Maybe you're not moving fast enough for locking to make a noticeable difference in stopping distance.

How fast were you going when you hit the brake?

Maybe you have to max out the brake force on the front and rear? Just guessing.
 
Has threshold braking worked in previous GT games. I don't get it, why even have ABS options if it doesn't make any difference?

Maybe you're not moving fast enough for locking to make a noticeable difference in stopping distance.

How fast were you going when you hit the brake?

Maybe you have to max out the brake force on the front and rear? Just guessing.

I'd have to go back and check my speed, but with the GT-R from that distance I'd say at least 100mph. I know the brakes locked without ABS, because there was tons of smoke from the moment I slammed the brakes. I should have skidded way past the mark for the ABS brake slam test, but I didn't. It shouldn't be so close you can't tell.

Locking you tires instantly from 100mph or so should cause a big difference. Anyway it's a simple test and it sure looks like they messed up on ABS. Maybe some other things too, but this is a simple test. Try it and tell me what results you get.

I don't know if it worked in previous games, because Prologue is my first in the series. It should work in any sim. It's job one, right behind calculating wheel slip under acceleration and gforces on a skid pad. Maybe it made sense for controllers back when they weren't analog, so you couldn't use variable pressure. I don't know enough about old Sony controllers.
 
ABS is always set to 1 in time trial isn't it? Wouldn't that have something to do with it?

Yeah, you can't quick tune in Arcade Time Trial mode, so I went to the Online Time Trials, so I could adjust ABS. I initially did the test in the Arcade Time Trial, but when lockups didn't effect stopping distance, I switched modes. I figured ABS would solve the problem. It didn't.
 
Threshold braking does work in prologue. Go to the high speed ring reverse and check out the top time (or at least, that's what it was) GT-D and you'll see that the fastest time I achieved there beat all those that used ABS.

The first corner went somewhat awry, but after that it's all smooth :)
 
OK first thing here JACKB - please do not double or in this case triple post, its simply not allowed here at GT Planet. If you need to add info to a thread and you are still the last person to have posted then use the edit button. I've merged the three posts together in this case, but please don't do this again.

Second a number of people here are new so may not know the degree to which this has already been discussed for GT4, in which case a read of the following thread will be very useful....

GT4 & Brakes

...a good 500+ posts on how braking is implemented in the GT series and how braking works in the real world. Well worth a read (and has a nice index and links in the first post to make navigation a lot easier).


Now onto the topic at hand. I used the Clio V6 (on S2's - Time Trail) for my tests, mainly because its short wheel base, relatively high COG and weight will all maximise load transfer and make what is occurring more obvious. I carried out the adjustments using the in-car set-ups.

To be honest it took me about 10mins at most to work out what the problem is that JackB is having.

But first a clarification on exactly what ABS (and this is particularly true of the real world) does not, and was not designed to do. ABS does not and can't guarantee to stop a car quicker, ABS was designed (and passenger car versions are still designed to this day) to allow you to steer and brake without worry of lock-up. All but the most advanced systems will not necessary reduce stopping distances at all. The difference in stopping distances between the two is not automatically a massive difference, and the number of factors involved are huge, but as a rough guide the more grip the tyres have, the less the difference will be, as you have more grip available before exceeding limit (lock-up becomes more difficult). JackB does not mention what tyres he used and this could be a major factor here.

Another flaw in his testing was that he states he simply got as much speed as he could before the start line and then hit the brakes, sorry but you need to be braking from exactly the same speed every time. And to ensure that you are consistent I would recommend at least six runs on each test (take a look at the tests in the GT4 & Brakes thread - this is the set-up we always used), otherwise a slight late brake on a single test will throw the results out.

However rather simply put if you just turn off ABS and then try threshold braking you are going to be bang out of luck, as you need to look beyond just flicking a switch.

When you disable ABS you are then left with the default brake bias of 5/5 (on all cars) and this is going to cause you problems for two main reasons. First for a lot of cars (and this does also depend on the tyres you are using) this is just too high, brake bias does not just affect the ratio of braking front to rear, but also the brake force itself. Set to high (and 5/5 certainly was for the Clio) and you are going to lock the brakes with a brush of the pedal. Always remember the brakes don't determine how quickly a car stops, tyres do, you have to match the brake force to the tyres if you are not going to use ABS.

The second and more critical factor here is that off brake bias, under hard braking (and that is exactly what we are talking about here) a massive amount of load moves to the front of the car, the weight distribution often ends up as high as 70%/30% in a car that can have a static distribution of 50%/50% (FWD cars can hit 80%-90% at the front under braking!!!). With a default brake bias of 5/5 the rears are going to lock up almost the second you brush the brake pedal.

I only had a quick play with the Clio last night, but moving to a better brake bias set-up (I finished with 4/2 if I recall correctly) and a few dozen runs with and without ABS later and I would have to say that you can see a difference. Without at least a data logger (as we have had in the past) it impossiable to say exactly what the difference is.

I would give Jack a 10/10 for starting these tests and showing an interest in the subject as a whole, however I think a few basic flaws exist in his methodology of testing.

I would recommend that anyone interested in the subject of braking take a look at the thread I linked to above and also download the first of my tuning guides, which covers a solid (and based on real world) method of brake bias set-up.


Regards

Scaff
 
OK first thing here JACKB - please do not double or in this case triple post, its simply not allowed here at GT Planet. If you need to add info to a thread and you are still the last person to have posted then use the edit button. I've merged the three posts together in this case, but please don't do this again.

This is one picky site. I just got to GT Planet 2 weeks ago and I feel like I'm on probation all ready. This is my first, but I see these warnings on here a lot.

Second a number of people here are new so may not know the degree to which this has already been discussed for GT4, in which case a read of the following thread will be very useful....

GT4 & Brakes

...a good 500+ posts on how braking is implemented in the GT series and how braking works in the real world. Well worth a read (and has a nice index and links in the first post to make navigation a lot easier).

Thanks for the URL. Very good information.

Now onto the topic at hand. I used the Clio V6 (on S2's - Time Trail) for my tests, mainly because its short wheel base, relatively high COG and weight will all maximise load transfer and make what is occurring more obvious. I carried out the adjustments using the in-car set-ups.

To be honest it took me about 10mins at most to work out what the problem is that JackB is having.

But first a clarification on exactly what ABS (and this is particularly true of the real world) does not, and was not designed to do. ABS does not and can't guarantee to stop a car quicker, ABS was designed (and passenger car versions are still designed to this day) to allow you to steer and brake without worry of lock-up. All but the most advanced systems will not necessary reduce stopping distances at all. The difference in stopping distances between the two is not automatically a massive difference, and the number of factors involved are huge, but as a rough guide the more grip the tyres have, the less the difference will be, as you have more grip available before exceeding limit (lock-up becomes more difficult). JackB does not mention what tyres he used and this could be a major factor here.

I find it odd, that you aren't speaking to me, but to the rest of GT Planet "about" me. It has the tone of a professor lecturing a class about a foolish student. I don't appreciate it. You probably don't get called out on that a lot, but that's the way it comes across. If I responded to you with "Scaff is wrong on this point... what he doesn't understand is..." I'd just appreciate a reply to me, not "about me" to the GT Planet community as if you are the commanding authority.

Couple of points. The Suzuka track has excellent traction. It's not a dirt road. I was using the stock tires on the GT-R for all tests.

Another flaw in his testing was that he states he simply got as much speed as he could before the start line and then hit the brakes, sorry but you need to be braking from exactly the same speed every time. And to ensure that you are consistent I would recommend at least six runs on each test (take a look at the tests in the GT4 & Brakes thread - this is the set-up we always used), otherwise a slight late brake on a single test will throw the results out.

Yes, class Jack B's flaw was that he didn't have precisely the same speed every time. Well, if using an automatic transmission from a dead stop on the same mark every time isn't going to give me the best shot at getting the same speed then what is? It's also difficult to hit the brake mark. There isn't any simple way in Prologue to accomplish a 100% scientific test.

The brake test in GT 4 sounds interesting, but I don't see anything like that in Prologue.

However rather simply put if you just turn off ABS and then try threshold braking you are going to be bang out of luck, as you need to look beyond just flicking a switch.

When you disable ABS you are then left with the default brake bias of 5/5 (on all cars) and this is going to cause you problems for two main reasons. First for a lot of cars (and this does also depend on the tyres you are using) this is just too high, brake bias does not just affect the ratio of braking front to rear, but also the brake force itself. Set to high (and 5/5 certainly was for the Clio) and you are going to lock the brakes with a brush of the pedal. Always remember the brakes don't determine how quickly a car stops, tyres do, you have to match the brake force to the tyres if you are not going to use ABS.

The second and more critical factor here is that off brake bias, under hard braking (and that is exactly what we are talking about here) a massive amount of load moves to the front of the car, the weight distribution often ends up as high as 70%/30% in a car that can have a static distribution of 50%/50% (FWD cars can hit 80%-90% at the front under braking!!!). With a default brake bias of 5/5 the rears are going to lock up almost the second you brush the brake pedal.

I only had a quick play with the Clio last night, but moving to a better brake bias set-up (I finished with 4/2 if I recall correctly) and a few dozen runs with and without ABS later and I would have to say that you can see a difference. Without at least a data logger (as we have had in the past) it impossiable to say exactly what the difference is.

I would give Jack a 10/10 for starting these tests and showing an interest in the subject as a whole, however I think a few basic flaws exist in his methodology of testing.

I would recommend that anyone interested in the subject of braking take a look at the thread I linked to above and also download the first of my tuning guides, which covers a solid (and based on real world) method of brake bias set-up.
Regards
Scaff

All this talk of brake bias is great, but I had the same tires, same brake bias, same everything on each run. I only did 100% braking and attempted threshold braking with and without ABS.

Even if you throw out the ABS results, I was surprised at how little difference I got with instant lockup vs threshold. That was my whole point. If you're telling me, that instant lockup stops just as quick as 100% pressure with ABS then that's all I was looking for. I would have expected threshold braking to be much better than smoking the tires for a couple hundred feet. I'm sure I could use more practice, but do you have a link to any physics about tire skidding from lockup?

You wrote this in one of the threads you linked for me...

Now what I expected to find was than a car fitted with ABS should stop quicker than a car without ABS, if the tyres lock under hard braking. Please be aware that threshold braking will be quicker than either of these, but thats another subject.

The reason behind this is that the ABS system is able to release and apply the brake many thousands of times a second when it detects that the tyres has exceeded its slip percentage. Without ABS you are simply waiting for the tyre to regain grip, if and when it does .

That's exactly what I would have expected as well and why I ran the tests. That's your quote above, not mine.

I still don't see anything in your text above, that explains why on a dry surface with straight line braking a car with locked wheels at 100mph will stop in almost exactly the same distance as on with ABS and no lockup.
 
This is one picky site. I just got to GT Planet 2 weeks ago and I feel like I'm on probation all ready. This is my first, but I see these warnings on here a lot.
You see the warnings a lot because we have a lot of new members here, the 'intake' rises whenever a new GT game is released. You are however quite right that we are a picky site, and quite honestly we are proud of that, what you will not find here are poor quality threads that descend into abuse and flaming matches. That we believe is a direct result of the AUP we have here at GT Planet and how strictly its enforced, however you are not asked (and will never be asked) to do anything that we don't already expect of every other member.


Thanks for the URL. Very good information.
Hope it is of interest.


I find it odd, that you aren't speaking to me, but to the rest of GT Planet "about" me. It has the tone of a professor lecturing a class about a foolish student.
I think that may be more reviling about yourself that anything else; yes I was posting to any reader of the thread in general, but I was not posting in a manner different to my norm and to be honest you are the first person who has ever 'taken offence' to it.

I could make the exact same claim about your 'I just realized not everyone here may know what threshold braking is.', you addressed that to a general audience rather than the member who incorrectly described threshold braking.


Couple of points. The Suzuka track has excellent traction. It's not a dirt road. I was using the stock tires on the GT-R for all tests.
Thanks for the clarification on the tyres, as it does make a difference and in regard to the track surface. Yes, in keeping with all purpose built circuits Suzuka has excellent traction, a factor that is going to minimise the difference between lock-up and threshold braking. The more grip the tyre/track interface give you, the greater the brake force that can be applied before lock-up occurs and the less lock-up you will get, and therefore the difference will be smaller.


Yes, class Jack B's flaw was that he didn't have precisely the same speed every time. Well, if using an automatic transmission from a dead stop on the same mark every time isn't going to give me the best shot at getting the same speed then what is? It's also difficult to hit the brake mark. There isn't any simple way in Prologue to accomplish a 100% scientific test.
I will be quite frank about this, your tone here is not going to do you any favours at all. Being blunt if you post up test results in which flaws exist in the method used then expect people to pick up on it, if you don't want that to happen then either don't post, develop better testing methods or listen to the people who reply. Getting defensive and sarcastic about it is not however advised.

Using the same speed to brake from each and every time is crucial if you are going to compare stopping distances, that's why every real world data test for stopping distances uses a 100mph-0mph or 60mph-0mph, as without this constancy the results are never going to be comparable.

Its also why I clearly said that all the tests on braking done on the other thread were taken from multiple runs, to help minimise slight differences in speed. No its not an easy thing to do at all and its does take a lot of time to do well, but if you want results that are going to be accepted and can be replicated then that is exactly what you need to do.



All this talk of brake bias is great, but I had the same tires, same brake bias, same everything on each run. I only did 100% braking and attempted threshold braking with and without ABS.

Even if you throw out the ABS results, I was surprised at how little difference I got with instant lockup vs threshold. That was my whole point. If you're telling me, that instant lockup stops just as quick as 100% pressure with ABS then that's all I was looking for. I would have expected threshold braking to be much better than smoking the tires for a couple hundred feet.
The brake bias point is critical to this in every way, with the default value of 5/5 and ABS turned off almost every car in the game is going to lock its rear tyres the second you touch the brake pedal. The default value to so far from realistic as to be absurd, without setting a bias that has some basis in reality (and that means a bias to the front - always) then you can't begin to start comparing the results with what you would expect in the real world.

Rather that dismiss what I have said why not actually give it a go, after all that is exactly what I did with your test. Do you think I just read it and then started to type? No, I went and put your tests into practice, then refined them using my own knowledge of how brakes work.


I still don't see anything in your text above, that explains why on a dry surface with straight line braking a car with locked wheels at 100mph will stop in almost exactly the same distance as on with ABS and no lockup.
I did cover this in my text above, ABS does not mean that you will stop quicker, its (apart from a small number of very expensive and rarely used system that principally exist for racing) aim is to allow people to steer while braking heavily. It can do it, but its not a guarantee at all, particularly if the tyres and track are providing a lot of grip already.

However even taking that into account, you have acknowledged that your methods do need further work and as such the results can't be taken as 'correct'.

With the right driver (who has the right degree of skill) threshold braking distances can be shorter than ABS or lock-up, but it is down to the skill of the driver and the set-up of the car. Which is exactly my point in regard to both method and more fundamentally brake bias. If the brake is not set correctly for a car it doesn't matter how good a driver you are the rears are going to lock before the fronts and you are never going to be able to threshold brake (which requires that you make the best use of the grip offered by all the tyres - not just the rear ones).

For this series of test to even begin to be done the first thing that needs to be done is get the brake bias set correctly for the car being used, without that fundamental piece of work done any and all results taht follow will be flawed.


Regards

Scaff
 
I think that may be more reviling about yourself that anything else; yes I was posting to any reader of the thread in general, but I was not posting in a manner different to my norm and to be honest you are the first person who has ever 'taken offence' to it.

OK. Since it's not a problem I'll reply to you in the same manner. I believe Scaff is incorrect in his assumption.

Using the same speed to brake from each and every time is crucial if you are going to compare stopping distances, that's why every real world data test for stopping distances uses a 100mph-0mph or 60mph-0mph, as without this constancy the results are never going to be comparable.

Of course. I mentioned, that I had no options to perform a better test in Prologue. I initially tried hitting a target speed, but I was consistently off by 1-3 mph +/-, so I choose using an automatic from a standing start to be reasonably consistent. I also never said I didn't do 6 or more tests. In fact I probably did about that many. I ended the original post in this thread with "maybe, I've done something wrong". I also used the word "seems" in the title. I didn't say my tests were perfect or definitive. I was looking for others, who could add to the discussion. You have, but I wouldn't call it case closed by any stretch yet.

Its also why I clearly said that all the tests on braking done on the other thread were taken from multiple runs, to help minimise slight differences in speed. No its not an easy thing to do at all and its does take a lot of time to do well, but if you want results that are going to be accepted and can be replicated then that is exactly what you need to do.

If you want I can show you tests in the thread you posted, that were less scientific than mine. One involved someone attempting to test drives around a track at 85% breaking vs 85% to 100% and 100% breaking. Now that's inconsistent.

The brake bias point is critical to this in every way, with the default value of 5/5 and ABS turned off almost every car in the game is going to lock its rear tyres the second you touch the brake pedal. The default value to so far from realistic as to be absurd, without setting a bias that has some basis in reality (and that means a bias to the front - always) then you can't begin to start comparing the results with what you would expect in the real world.

Rather that dismiss what I have said why not actually give it a go, after all that is exactly what I did with your test. Do you think I just read it and then started to type? No, I went and put your tests into practice, then refined them using my own knowledge of how brakes work.

I thought about saying, Scaff misunderstood me here, but I made my point. I didn't dismiss your brake bias point at all. It's very good information and I've read Going Faster, Speed Secrets and a couple others. I'm not going to claim I understand as much as you do, I just didn't think it pertained significantly to my particular test. The brake bias never changed for any of my 4 tests. I wasn't dismissing your brake bias info.

I did cover this in my text above, ABS does not mean that you will stop quicker, its (apart from a small number of very expensive and rarely used system that principally exist for racing) aim is to allow people to steer while braking heavily. It can do it, but its not a guarantee at all, particularly if the tyres and track are providing a lot of grip already.

I've seen articles, which state ABS will improve straight line braking vs lockups. Maybe not threshold, but certainly 100% smoking tires from the get go, lockups. That's the reason for my test. I still don't think smoking tires at 100 mph should stop as quickly as ABS in a straight line on a dry surface.

However even taking that into account, you have acknowledged that your methods do need further work and as such the results can't be taken as 'correct'.

I do agree, I could do more testing, but I'm still not convinced.

With the right driver (who has the right degree of skill) threshold braking distances can be shorter than ABS or lock-up, but it is down to the skill of the driver and the set-up of the car. Which is exactly my point in regard to both method and more fundamentally brake bias. If the brake is not set correctly for a car it doesn't matter how good a driver you are the rears are going to lock before the fronts and you are never going to be able to threshold brake (which requires that you make the best use of the grip offered by all the tyres - not just the rear ones).

I can agree with that comment. I could expect a small, but important decrease in stopping distance from threshold braking and it does require skill. Maybe my title thread would have been better if it said, "Smoking tires at 100 mph stop as quickly as ABS braking".

For this series of test to even begin to be done the first thing that needs to be done is get the brake bias set correctly for the car being used, without that fundamental piece of work done any and all results taht follow will be flawed.

BTW, here are two articles, that do show ABS can decrease braking distances on dry roads, so it's not a consensus agreeing it doesn't effect stopping distance. I'm sure you can find other statements saying it doesn't help braking, I'm just pointing out, that it's not a consensus.

Click here and here.

I take it you have no interest in doing your own tests. Are you convinced Prologue is handling all of this 100% correctly?
 
BTW, here are two articles, that do show ABS can decrease braking distances on dry roads, so it's not a consensus agreeing it doesn't effect stopping distance.

The 2nd article JackB linked
It is important to remember that ABS can increase straight-line stopping distances beyond that of threshold braking in a non-ABS equipped car.

Sorry, you guys are having so much fun quoting everything i thought i'd jump in too :)
 
Sorry, you guys are having so much fun quoting everything i thought i'd jump in too :)

Yeah, and that's not even my biggest issue.

It's that 100% smoking tires from 100 mph tied ABS for stopping distance in my test runs. I'd expect with threshold and ABS it would be close or maybe a win to threshold with a skilled driver, but skidding, smoking tires...?

I would have figured ABS would have beaten smoking, skidding, locked up tires by about 30% at least in stopping distance. I wouldn't have figured it would be close. Everytime I've ever locked up tires in real life, it felt like I was never going to stop. Skidding seems to mean, sliding farther from my experience.
 
Well to be fair your (Scaff's that is. Sorry I didn't see the intervening posts, they came too quickly) comments do sometimes sound a bit high-handed. On the other hand I realise that there are a lot of kids who post here and being a moderator it must become a bit tiring :-)

On topic: Yes I've noticed FF cars have a lot of front bias for braking. The number of times I've come down twisty mountain roads and had the front brakes stink where they've got so hot!

One question though, if I've followed this correctly (and I haven't finished the A races yet so can't turn off ABS myself) the default brake balance is 50/50 so the cars skid a lot without ABS. Shouldn't they then take longer to stop than ABS with brakes full on?

I'm also not sure how EBD is modelled in GT5P. I remember my PT Cruiser would squirm under heavy braking as it only had ABS, whereas the Seat we've got now keeps you "straight and true". I haven't seen that in GT5P so far.

Finally, I always imagined that any car without ABS would lock it's wheels under heavy braking but since I upgraded my suspension (in real life this is) I can push the pedal as hard as I can and the tyres don't lock up. So far I've only tested in the dry and at 50 - 60km/h.
 
OK. Since it's not a problem I'll reply to you in the same manner. I believe Scaff is incorrect in his assumption.
Quite frankly I don't care how you reply to me as long as it sticks to the AUP.


Of course. I mentioned, that I had no options to perform a better test in Prologue. I initially tried hitting a target speed, but I was consistently off by 1-3 mph +/-, so I choose using an automatic from a standing start to be reasonably consistent. I also never said I didn't do 6 or more tests. In fact I probably did about that many.
The only issue with this is that averaged out over a good number of tests your initial method would actually be far more accurate that the one you switched to.



If you want I can show you tests in the thread you posted, that were less scientific than mine. One involved someone attempting to test drives around a track at 85% breaking vs 85% to 100% and 100% breaking. Now that's inconsistent.
You may want to take a closer look at those tests and exactly who carried them out, I don't think that you will find anything wrong with the methods I used in any of the tests that I carried out and you will also note that I also say that I always accept a margin of error in all my testing.



I thought about saying, Scaff misunderstood me here, but I made my point. I didn't dismiss your brake bias point at all. It's very good information and I've read Going Faster, Speed Secrets and a couple others. I'm not going to claim I understand as much as you do, I just didn't think it pertained significantly to my particular test. The brake bias never changed for any of my 4 tests. I wasn't dismissing your brake bias info.
You are however ignoring it completely from testing, so I will ask the question directly. How do you expect to get even remotely accurate results from these tests if the brake bias from the car is set-up in such a manner as to make threshold braking impossible?



I've seen articles, which state ABS will improve straight line braking vs lockups. Maybe not threshold, but certainly 100% smoking tires from the get go, lockups. That's the reason for my test. I still don't think smoking tires at 100 mph should stop as quickly as ABS in a straight line on a dry surface.

BTW, here are two articles, that do show ABS can decrease braking distances on dry roads.

Click here and here.

OK first off go back and ready what I said (not what you think I said), actually here it is again....

Scaff
I did cover this in my text above, ABS does not mean that you will stop quicker, its (apart from a small number of very expensive and rarely used system that principally exist for racing) aim is to allow people to steer while braking heavily. It can do it, but its not a guarantee at all, particularly if the tyres and track are providing a lot of grip already.

....I did not say that the stopping distances were the same, what I said was that ABS is not a guarantee of stopping quicker than lock-up, exactly as the piece I have highlighted quite clearly says.

Now to the two articles you have linked to, the first one is the most detailed and actually a handy reference document, with the following being a useful quote...

the benefit of ABS might not be seen unless stops on a wet surface are also performed

and

This indicates that ABS is more important on wet asphalt than dry asphalt

...as we are talking (in terms of your tests) of bone dry conditions on a high grip racing surface (that generally for most tracks gives a Mu of over 1.0 public roads at best will generally give an Mu of 0.8 - Mu = co-efficent of friction) and sticker that normal tyres (S tyres in the GT series are grippier than 'real' road PD state that N2 and N3 tyres come closest and testing backs this up) its no surprise we are not seeing an easily mesurable difference between ABS and lock-up.


The second of your links does not state what you claim at all, the entire section of it that covers ABS in stopping (and not ABS' role in traction control) reads as follows....

The most common and well-known traction control device is the Anti-Lock Brake System (ABS). ABS is designed to prevent your wheels from locking up during panic or hard braking. When braking, if your front wheels lock-up, steering control is lost and your car will continue in the same path as before you attempted to brake. The system consists of a host of speed sensors and a central computer. Speed sensors are located at the wheels of the car, which tell the computer how fast they are turning. The computer constantly evaluates the speed of the vehicle and the speed of the wheels. When the brake pedal is depressed and the speed of the wheel reaches or get close to locking-up, the ABS computer will then modulate the amount of brake pressure (or “pump” the brakes), as fast as fifteen times per second, on that wheel. This continuing modulation or pumping will prevent or correct wheel lock-up and allow the driver to brake and steer. ABS systems do vary from auto manufacturer to auto manufacturer. It is important know if the car you are driving is equipped with ABS and how to brake if ABS is activated. Shortly after its introduction in the marketplace, there were insurance industry studies that showed ABS equipped cars were in a higher rate of accidents then those not equipped. In this study, it was shown that the most frequent factor in these accidents was driver error. Drivers were not putting enough pressure on the brake, not holding brake pressure long enough or trying to pump the brakes. Evidence also suggests that drivers were over confident when driving an ABS equipped car and were not allowing for a safe following or braking distance.

To correctly use the brakes in an ABS equipped car in a panic situation, the driver must apply the brakes 100 percent, using all available force. The ABS computer will prevent brake lockup and the tires sliding on the travel surface. This will allow the driver to steer around the threat. It is important to remember that ABS can increase straight-line stopping distances beyond that of threshold braking in a non-ABS equipped car. ABS offers drivers, in an emergency situation, the ability to maintain steering control so they can steer clear of an obstacle or threat. Current ABS systems give feedback to the driver to let them know it is activated and operating during the current braking maneuver. The most common way that ABS communicates to the driver is a pulsing sensation felt in the braking foot or a rattling noise during braking. This is normal operation and is telling the driver ABS is working. As discussed above, do not attempt to modulate the brake yourself and remember to use all the brake force available. The ABS system will take care of the modulation for you and allow you to steer around a threat.

...in fact the section I have highlighted clearly states that ABS braking can take longer than threshold braking and at no point at all is ABS vs. lock-up even discussed in it.

Here's a clip from Bosch (one of the largest manufacturers of ABS systems in the world) showing the advantages of ABS vs lock-up...



...notice that they do not make any claim that ABS will stop you quicker (because it does not do so under all circumstances) rather that the principal benefit of ABS is to allow you to steer while braking, which is exactly the point I have maintained. Basing part of a test on the premise that ABS will always stop quicker than lock-up is a flawed approach as its a false premise, it will not always stop you quicker, its not what ABS was designed to do.

I work in the motor industry (have done for most of my working life) and I train dealership staff for a living. I spent nearly five years of that time designing and delivering product training, I know the theory and practical side of safety systems of this nature. I have taught the classroom side of it and demonstrated the 'real world' side of it on tracks and proving ground. I have never and would never make the claim that ABS will always stop you quicker, quite simply because I know its not true (and on snow, ice and loose gravel ABS is a far worse option that lock-up as the systems get totally confuse and braking distance in these situations increase).


I take it you have no interest in doing your own tests. Are you convinced Prologue is handling all of this 100% correctly?

I would advise you to take a look at my post history and the amount of testing I have done over the entire GT series before making sweeping statements of that nature. I've at no point said that I have no interest in testing (quite the opposite) and has probably the largest history of physics testing across a wide range of driving sims of any member here.

I've also never said that Prologue is 100% correct, again if you actually took the time to read my posts and threads you would know this.

I am going to be very, very blunt about the next point, I do not like people putting words in my mouth, I have never come close to saying anything of the nature you has above, not have I come close to implying it. So don't imply it on my behalf.


Regards

Scaff
 
Quite frankly I don't care how you reply to me as long as it sticks to the AUP.

This interchange got off to the wrong start, because I was offended by you taking the third person narrative in discussing my tests in your reply. A forum is like a virtual community and those reading a thread exist in a kind of virtual room. In a virtual room or real life room, you speak directly to each other. Using third person is rude, IMO. Especially, when the discussion is to poke holes in my very brief and admittedly so, tests. Try using third person with someone standing next to you at a party, while you discuss them and see if it's as readily accepted technique as you think. Believe me, it isn't. Third person is at times described as being an omniscient narrator.

It's like talking about grandpa, while he's in the room. Anyway, I've gotten that off my chest. Time to move on. You definitely have a passion for racing and GT, so I appreciate your posts, although they often come across as a bit pompous, IMO. Hopefully, that will be taken as constructive criticism.

The only issue with this is that averaged out over a good number of tests your initial method would actually be far more accurate that the one you switched to.

I'm not sure running through the braking marker at 97-103 mph would have been more accurate. I chose standing start in automatic, because I thought it would be more accurate and easier. I could go back and check, but my guess is the mph from a standing start with automatic would be within those tolerances and it's easier to hit the mark, when I was watching my mark and not the speedometer. I believe it did average out though.

You may want to take a closer look at those tests and exactly who carried them out, I don't think that you will find anything wrong with the methods I used in any of the tests that I carried out and you will also note that I also say that I always accept a margin of error in all my testing.

Most tests and your tests were fine, but you said all the tests in the links you gave. I read a few. I showed one where it was far from scientific. This is a game after all and we don't have the tools in game to do extremely accurate testing in all areas.

You are however ignoring it completely from testing, so I will ask the question directly. How do you expect to get even remotely accurate results from these tests if the brake bias from the car is set-up in such a manner as to make threshold braking impossible?

Forza lists front and rear weight percentage on every car. Brake bias is a tuneable setting. I've read quite a bit on the web and in Speed Secrets, Going Faster etc, about the subject. I've not gotten into tuning much with GT yet, because it seems a bit basic and the increments are high, different terminlogy is used (ie 10 is high, 1 is low etc, instead of foot pounds or whatever) for each category available, but I certainly will soon.

OK first off go back and ready what I said (not what you think I said), actually here it is again....

....I did not say that the stopping distances were the same, what I said was that ABS is not a guarantee of stopping quicker than lock-up, exactly as the piece I have highlighted quite clearly says.

You keep going back to threshold vs ABS. That's a valid discussion and I'd agree with that statement. I'm also very happy to know that threshold braking does work in Prologue. I need more practice modulating the brakes. I offered this thread as a "question" and request for more discussion, not some foregone conclusion. The post title used "seems" and I ended my post with "Maybe, I'm doing something wrong".

The results that still puzzle me are not the ones about threshold with and without ABS or vs ABS, it's the ones of Lockup vs ABS. If you can point me to scientific testing, that shows 100% lockup at 100 mph in straightline braking stops just as quickly as ABS at 100 mph. That's where I'm at. If so, then assuming I have no need to turn at the end of a long straight, then I might as well slam the brakes at my break marker with ABS or without to elimate the chance of error missing my mark, since I'll stop just as quickly in either case. I'm OK with the ABS is better for turning and threshold is better than ABS in the hands of a skilled driver stuff. It's this other question, I'm still wondering about.

Now to the two articles you have linked to, the first one is the most detailed and actually a handy reference document, with the following being a useful quote...

and

...as we are talking (in terms of your tests) of bone dry conditions on a high grip racing surface (that generally for most tracks gives a Mu of over 1.0 public roads at best will generally give an Mu of 0.8 - Mu = co-efficent of friction) and sticker that normal tyres (S tyres in the GT series are grippier than 'real' road PD state that N2 and N3 tyres come closest and testing backs this up) its no surprise we are not seeing an easily mesurable difference between ABS and lock-up.

Good stuff, but that article did specifically state ABS does help with straightline braking, so I linked to it.

The second of your links does not state what you claim at all, the entire section of it that covers ABS in stopping (and not ABS' role in traction control) reads as follows....

...in fact the section I have highlighted clearly states that ABS braking can take longer than threshold braking and at no point at all is ABS vs. lock-up even discussed in it.

I posted it to show the scatter graphs of results showing all drivers on dry pavement had improved stopping distances in a straight line on dry pavement.

Here's a clip from Bosch (one of the largest manufacturers of ABS systems in the world) showing the advantages of ABS vs lock-up...

...notice that they do not make any claim that ABS will stop you quicker (because it does not do so under all circumstances) rather that the principal benefit of ABS is to allow you to steer while braking, which is exactly the point I have maintained. Basing part of a test on the premise that ABS will always stop quicker than lock-up is a flawed approach as its a false premise, it will not always stop you quicker, its not what ABS was designed to do.


Thanks. It say's "the driver brakes hard, but the car doesn't respond...". Yes, he locked up. They address the well known advantage of being able to manuver while turning with ABS, but not whether the car skidding in lockup would have stopped sooner if it hadn't have locked up. That's what I'm looking for, not the ABS is better for steering while under braking. You keep trying to get me to agree with that point, but I do agree.

I work in the motor industry (have done for most of my working life) and I train dealership staff for a living. I spent nearly five years of that time designing and delivering product training, I know the theory and practical side of safety systems of this nature. I have taught the classroom side of it and demonstrated the 'real world' side of it on tracks and proving ground. I have never and would never make the claim that ABS will always stop you quicker, quite simply because I know its not true (and on snow, ice and loose gravel ABS is a far worse option that lock-up as the systems get totally confuse and braking distance in these situations increase).

That's great, but I'm just looking for testing that shows actual results. I've read differing opinions from other people in the industry like yourself.

Honest question here. Would you say then that on dry flat pavement in a straight line stopping by slamming on the brakes 100% is just as effective a method for stopping in GT as using ABS and slamming on the brakes? If so, should the average driver (not threshold capable, ie it becomes worse, not better) just slam on the brakes and smoke the tires (assuming no tire wear issues in a 3 lap race) in these situations? I'd have to go back to my Skip Barber tests, but that just doesn't seem like the best way to brake. It's very easy, but I'm just surprised.

I'll have to read some of your earlier posts on trail braking with and without ABS too. And don't take that as sarcasm. I am very interested and would expect if you've done testing it would be helpful.

Lastly, how does GT handle tire temperature and loss of grip? Thanks, and hopefully we can get past the initial disagreement on tone. If not, ban me. :)




I would advise you to take a look at my post history and the amount of testing I have done over the entire GT series before making sweeping statements of that nature. I've at no point said that I have no interest in testing (quite the opposite) and has probably the largest history of physics testing across a wide range of driving sims of any member here.

I've also never said that Prologue is 100% correct, again if you actually took the time to read my posts and threads you would know this.

I am going to be very, very blunt about the next point, I do not like people putting words in my mouth, I have never come close to saying anything of the nature you has above, not have I come close to implying it. So don't imply it on my behalf.


Regards

Scaff[/QUOTE]
 
Have you tried any different cars yet to see if it's any different? The GT-R does seem very artificial in braking and handling probably thanks to all the electronics.
 
Try no assists (including ABS off) in the Ferrari 512B, It sure seems like the thresh-hold braking is quite accurate. The GTR is a rolling supercomputer, turning off the ABS on this car seems a little silly to me. Just my opinion, I hope I don't offend anyone.
 
I believe Scaff is being quite counter productive here. Brake bais has nothing to do with the test results as it was the same in each test. Sure the back wheels may lock straight away, but if that is the same in every test then it has no impact on the data. You are still getting information from the front tyres which very well should tell you that not locking up the wheels is a faster way to stop than locking them.

Scaff was also saying that track friction and also tyre selection play an important part, however this is misinformation also. Any tyre on any surface will have more grip if it is not sliding and if you agree with this fact then you also agree that talking about track surface is simply trying to muddy the waters if all tests are conducted equally.
 
Honest question here. Would you say then that on dry flat pavement in a straight line stopping by slamming on the brakes 100% is just as effective a method for stopping in GT as using ABS and slamming on the brakes? If so, should the average driver (not threshold capable, ie it becomes worse, not better) just slam on the brakes and smoke the tires (assuming no tire wear issues in a 3 lap race) in these situations? I'd have to go back to my Skip Barber tests, but that just doesn't seem like the best way to brake. It's very easy, but I'm just surprised.
Just answering your straight questions, on dry tarmac with good tyres and a lot of grip I would say the difference in straight line stopping could well be minimal. ABS should in theory stop slightly quicker, but it depends entirely on the type of ABS that GT5:P is modelling, as a number of different systems exist, some more effective than others.

Its highly likely (and your tests to a degree back this up) that to most common road car ABS systems are being modelled, in that as lock-up is detected the brakes are released to regain grip. This means that ABS will not cut in until lock-up actually occurs.

Now as lock-up is less likely to occur at higher speeds (I will go into why in a moment) the difference between ABS and non-ABS stops do not come into play until a certain speed is reached. A factor that means we are not looking in a difference across the whole braking zone, but a smaller part of it.

The reason why lock-up is less likely to occur at higher speeds (note that's less likely - not imposable) is because of what causes it, as mentioned earlier lock-up happens when a tyres slip percentage is exceeded. So lets image a tyre has a slip percentage of 10%, for lock-up to occur at 100mph (road speed) the tyre would have to be rotating at under 90mph, while for lock up to occur at 30mph (road speed) the tyre would have to be rotating at under 27mph. So the difference in road to tyre speed before lock-up reduces as speed reduces, which is why you are more likely to see tyres locked-up in slower corners on a track and stops to standstill on the public road.

So if we only start to see lock-up start to occur at slower speeds on the track (and greater tyre/track grip levels will make this more likely) we end up with the difference on makes to the other being massively reduced.

So why do we need ABS? If it doesn't guarantee shorter stopping distances, well in the most straightforward terms for road use, because it allows you to still steer. The vast majority of drivers either drive to close to the car in front or brake too late (or both), reduced stopping distances often would make no difference at all, but being able to steer around and avoid an accident will.

On the track most drivers will also want to (or naturally do) carry some of the braking into the corner, with locked tyres thsi would be impossible and a trip to the gravel would be the result. Not to mention (and not modelled in GT) that you would flat-spot the tyres when locking up, which causes a huge number of problems with handling and future braking.

Good brake control is about a lot more than how quickly you can stop, I believe you have the Speed Secrets series of books, if so have a read of pages 40 and 41 of the first book. Its quite interesting (if a bit brief) in regard to ABS in racing and on the track.

As far as technical papers that look at ABS vs lock-up stopping distances, you will struggle to find them, as its just not generally looked at. The paper you linked to (which is a damn good read) does cover it to a degree, but in a more general look at all factors involved in braking.

Now given all of the above one type of ABS system is worth a mention here. Some very, very expensive and high end ABS systems are actually capable of monitoring road and wheel speeds individually and comparing it to known tyre data. This is then used to ensure that the ABS kicks in and releases the brake pressure the millisecond before the tyres lock-up. This system will reduce stopping distances, because it is effectively the ultimate in threshold braking.

It is however very rare and expensive and does have one rather major drawback, it has to be reporgrammed every time you change tyre brand and is subject to problems with tyre wear or extreme environmental conditions.



I'll have to read some of your earlier posts on trail braking with and without ABS too. And don't take that as sarcasm. I am very interested and would expect if you've done testing it would be helpful.

Lastly, how does GT handle tire temperature and loss of grip? Thanks, and hopefully we can get past the initial disagreement on tone. If not, ban me. :)

No ban needed at all, and I will certainly be looking at re-doing a lot of my GT4 tests (and I hope a lot more) as and when time allows.




I believe Scaff is being quite counter productive here. Brake bais has nothing to do with the test results as it was the same in each test. Sure the back wheels may lock straight away, but if that is the same in every test then it has no impact on the data. You are still getting information from the front tyres which very well should tell you that not locking up the wheels is a faster way to stop than locking them.
I'm sorry but brake bias does have rather a lot to do with these tests (or any brake test) being worthwhile.

If the back tyres lock up the second you hit the brakes when you are trying to threshold brake then you are not threshold braking. The test becomes one of lock-up compared to lock-up. Threshold braking, by its very definition requires that the best use be made of all tyres to ensure that stopping distances are optimised, without correct bias this is never going to occur and all you end up doing is comparing lock-up with lock-up. Given that its little wonder no measurable difference was seen.



Scaff was also saying that track friction and also tyre selection play an important part, however this is misinformation also. Any tyre on any surface will have more grip if it is not sliding and if you agree with this fact then you also agree that talking about track surface is simply trying to muddy the waters if all tests are conducted equally.
I'm not trying to muddy the water at all, simply explaining why the results may well have ended up as they are. The greater the level of grip available then the less lock-up you are going to see. The less lock-up you get the less difference between threshold and lock-up braking distances and the harder it is to either see or measure the difference.

This is neither misinformation, which implies its incorrect, which is simply not true (unless you are saying that higher grades of surface and better tyres don't give more grip and that more grip reduces the likelihood of lock-up). Nor is it muddying the water in any way, its a perfectly accurate statement about the nature of the test conditions effecting the results.

To say that they have no bearing on how easy it is to see the difference is quite simply not correct and lower grade tyres would help in regard to the tests (but not as much as good telemetry information and data logging would).


Regards

Scaff
 
I was one of these that switched off all aids except ABS because the first time i tried it off i was jumping on the brakes like a loon and overshooting everything by a mile,
Now i swear by turning off the ABS i've found i can leave my braking a lot later with a careful combination of threshold and engine braking using manual of course,
I've found it takes a very fine balance and precision consistency but its so satisfying when you can pop down the inside approaching a bend and still exit on the right line.
 
I believe Scaff is being quite counter productive here. Brake bais has nothing to do with the test results as it was the same in each test. Sure the back wheels may lock straight away, but if that is the same in every test then it has no impact on the data. You are still getting information from the front tyres which very well should tell you that not locking up the wheels is a faster way to stop than locking them.

Scaff was also saying that track friction and also tyre selection play an important part, however this is misinformation also. Any tyre on any surface will have more grip if it is not sliding and if you agree with this fact then you also agree that talking about track surface is simply trying to muddy the waters if all tests are conducted equally.

Honestly, I kind of felt the same way. We could talk about weight transfer, weight balance, brake bias, rebound, damping, shock stiffness, tire pressure, whether the road was perfectly flat etc.

All of those things are factors in how quickly a car brakes or whether ABS is needed etc., but I agree it's muddying the waters.

The basic issue is that on a flat road (Suzuka's front straight) in Prologue on dry pavement, why is it that the car seems to stop in the identical distance with 100% brake pressure compared to ABS.

I slammed the brakes and viewed this from the outside the car view. The tires smoked instantly and squealed from the start. I would have to believe the GT-R had lost traction at that instant and skidded to a stop. Should the brakes have instantly smoked? Should the tires have instantly locked up? I would think they would in real life as well as in Prologue.

The burning question I have is why wouldn't I have slid way way way past my ABS stop with 100% lockup and screaming brakes? That's the big question. Why not slam the brakes every time on a straight if you stop in the same distance. Tire wear isn't an issue in Prologue.

I still believe the skidding GT-R should not have stopped as quickly as the ABS stop. I just figured a skidding car has lost traction and would skid for a greater distance.

Scaff, are you saying the skidding car stops just as quickly as one utilizing ABS with a GT-R? Remember, I gave the exact marks, car, transmission etc I used so you could replicate my tests. Does that make sense to you? It still doesn't to me. It's an honest question.

It does appear that threshold braking works from reading more posts. I've used it consistently in other sims and it just didn't feel right in some of the cars I was driving. Although, I'm loving the G25 wheel, Microsoft's wheel had a vibration that intensified as you reached the edge. This made it much easier to feel the proper point for threshold braking and losing traction on turns. The G25 has a much more solid feel though, so I'm happy with it too. Anyway, my initial thoughts about threshold braking came from the 100% lockup skidding. I'm used to seeing cars lockup and skid for 30% or more distance than a car that didn't lock. I don't know how many times I've seen cars skid past me in other sims. My tests just don't seem right with the GT-R. It just feels like it should be skidding way past the ABS marks. Try it yourself.

And I'd like to say thank you for continuing to contribute to this discussion. I enjoy learning more about racing and the physics of racing. My first racing game was Indy 500 on the PC back in the 80's. They get better every year, but they still leave out certain calculations. Some on purpose to make it more accessable for the masses, others, because they screw up or don't get around to it and others still, because they don't have the processing power to calculate everything, so they cheat a bit.

Prologue has been a blast to play, I just want to understand more about how they model some of the cars behavior.
 
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