Braking Differences in GT5 are Non-existent?

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YamauchiSanFan

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I've been noticing over and over again that my braking distances for different cars are pretty similar given the same tire compound. So, I went to High Speed Ring and did some tests. I put the car in bumper cam and would get up to 100mph before the start line, and as soon as the top of the speedometer would touch the start line I would jam on the brakes coming to a full stop. It really didn't matter what car I drove, just what tires I had on, because they all stopped in the same amount of time/distance. The super-heavy Dodge Challenger R/T stops as quickly as the Corvette ZR-1 when they are both fitted with Hard Sport tires (a default on both).

The two cars are dramatically different in total weight and brake systems. The Challenger weighs 4135lbs. and is one of the worst braking cars on the road requiring 136ft. to stop from 60mph (Road and Track, 10-09). The ZR-1 weighs 3365lbs. and only requires 112ft. to stop from 60mph (Road and Track, 6-10). That is over 1 1/2 car lengths (relative to the ZR-1) difference between the two in braking distance.

If this has been discussed I sure had a hard time finding it because I certainly looked. If there has to be a single issue with they physics in this game that overwhelms the others, this has to be it.
 
you have to manually handicap some cars which has worse brakes IRL to replicated that difference, for example an american junker might have brake force of 3F/1R compare to a NSXR with 4F/2R.

It does kind of sucks they didn't have realistic figures for each car stock but what can you do.
 
ive noticed this too, old american muscle cars, like the '70 challenger, came with 4 drum brakes made out of beer bottle caps, that cant dissipate heat in the slightest. but seems to stop like a modern car in PD's world, maybe "the dealership" upgrades to disk's? but thats fine, keeps me out of the wall!
 
I wondered why I was getting good at judging braking.
I jump in a new ride and get comfortable really quickly.
 
YamauchiSanFan
The two cars are dramatically different in total weight and brake systems. The Challenger weighs 4135lbs. and is one of the worst braking cars on the road requiring 136ft. to stop from 60mph (Road and Track, 10-09). The ZR-1 weighs 3365lbs. and only requires 112ft. to stop from 60mph (Road and Track, 6-10). That is over 1 1/2 car lengths (relative to the ZR-1) difference between the two in braking distance.
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It would be interesting to know if those cars have the same tyres, etc etc. The coefficient of grip between the tyre and the road determines the available force to slow the car. The grip is then influenced by the weight transfer during braking, which will depend on wheelbase and vehicle CG height, although the total weight remains the same, so if you ignore the non-linearity of the grip-load curve you could argue the total braking force remains the same regardless of weight transfer (the reality is of course, it doesn't). So you should see some differences in stopping distances, but if in PD's model, the tyre's grip is the key (only?) factor, then of course different cars with the same tyres will stop in roughly the same distance from the same speed. It's hard to know if PD account for lateral weight transfer, but given everything else, they must do, the handling would be fundamentally wrong if they didn't.

What I doubt they've modelled is things like mechanical efficiency, maybe inertia of wheels, etc. the things which can make a car slow better/worse even given the same tyres, weight transfer, road surface, etc.

Plenty of food for thought here: http://www.stoptech.com/tech_info/tech_white_papers.shtml (I am not associated with stoptech in anyway, just happen to have interesting articles).

IMO, and very much IIRC.
 
I'd be interested to see how this changes with ABS off? Apologies if you mentioned it and I missed it!

I usually play ABS=1 but have been turning it off lately trying to gold more licences, the brake balances needed are *very* different from those I like with ABS on.

As a side note, would a '70s Challenger even have ABS?
 
I've seen a few threads on brakes and ABS, what you guys are saying is reflected in what I've seen in other threads and that is that the brakes in GT5 are basically wrong.

It's the only way to describe it, whether it's ABS being on cars it shouldn't be on (i.e. historic / vintage cars), the standard settings of brakes (5 fr / 5 rr), the power of the brakes and the differences between ABS on and ABS off.

Some guys have got quite technical about it and gone into alot of detail, but the general concensus is that Polypony have made a complete hash of how the bakes are in GT5 compared to how the brakes and ABS are in real life.
 
Someone will be along any moment to tell us how PD have got it right, because all that matters in determining braking/stopping distance is the rubber you roll on *rolls eyes*
 
Piotrov
I guess thats why brake upgrades were never implemented in GT5.
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- All standard brake systems in GT have instant response;
- Their braking power can be increased simply by adjusting the brake controller;
- Brake fading or failure are not simulated;
- Brake rotor and brake pad temperatures are always optimal

Since brakes in GT5 are so perfect, brake upgrades wouldn't make any sense.
 
danjama
Someone will be along any moment to tell us how PD have got it right, because all that matters in determining braking/stopping distance is the rubber you roll on *rolls eyes*
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If you have the same braking force on every car, then all that really DOES matter is the rubber.

The problem with GT5 is that each car comes with a brake balance controller that acts as an infinitely tuneable aftermarket brake set. With ABS set at 1, I can get many cars to stop more comfortably by spamming the slider all the way to 10. Like Shirakawa says: the brake balance controller is effectively all the brake upgrade you'll ever need. In fact, it's a much better upgrade than "Racing Brakes" ever were in GT4.

As others have said, it's the brake force settings that are not accurately replicated for each car. For many cars, it's too easy to get their brakes locked up versus real life. Taking it down to F/R: 2/1 more accurately represents what kind of braking you might get out of an econobox with rear drum brakes. Yet all cars default to 5/5, which is so powerful it can lock the brakes with just a touch of the controller/pedal with the ABS off.

Not going to complain. One less part I have to buy for my race builds. But it takes a lot of the fun out of testing supposedly "stock" set-ups.
 
I'm curious about how off this actually is. Now, obviously, this isn't accurate to real life, but it would be hard to determine why that is the case.
Is it because of a problem with the way brakes are modeled? Or is it because all cars in the game come with a (inaccurately set) brake balance controller? Or is it because all of the cars can be equipped with identical tire compounds? I'm guessing it is more a case of the latter two than the first one, but I'm not sure if there would be any way to prove such a thing.


There are certain things that must be kept in mind, though:
  1. By very nature of how the GT5 engine is designed, no car built prior to the 1980s is going to have accurate braking (or handling, for that matter) performance compared to how they were back in the day.
  2. The effect of weight on braking performance isn't nearly as important as most people tend to think it is. In fact, it is fairly close to completely irrelevant. Not quite, but close.
 
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Also you have to consider that in GT5 the ABS implementation is faulty. It acts as a supremely good stability control with dynamic brake distribution, able to maximize braking power for each wheel indipendently (this is why the default brake distribution doesn't make sense. It's merely a "suggestion" for the ABS driving assits). Also it doesn't operate in pulses like real ABS systems, but smoothly and seamlessly.

If you take the ABS off you get a more or less realistic brake balance by setting it to 4/1 (or anything else biased about 70-85% to the front axle depending on the car). The braking itself also seems more realistic. However the issue that it's impossible to reproduce real life stock braking performance remains.
 
SHIRAKAWA Akira
Also you have to consider that in GT5 the ABS implementation is faulty. It acts as a supremely good stability control with dynamic brake distribution, able to maximize braking power for each wheel indipendently (this is why the default brake distribution doesn't make sense. It's merely a "suggestion" for the ABS driving assits). Also it doesn't operate in pulses like real ABS systems, but smoothly and seamlessly.

If you take the ABS off you get a more or less realistic brake balance by setting it to 4/1 (or anything else biased about 70-85% to the front axle depending on the car). The braking itself also seems more realistic. However the issue that it's impossible to reproduce real life stock braking performance remains.
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Impossible mostly because we don't know what settings will produce real life braking exactly. It's the same issue with the tires. We have a rough idea of what PD thought each car's tires are supposed to be, but we can't be sure.

GT5's ABS acts like a stability control system because it's perfect. Older ABS systems will react slower, or will not be as sensitive to locking on the rear axle, or will have any number of other differences to GT5's ABS. The same as stability control.

Weight is an interesting thing. In the one instrumented brake test I've done (and it's the only one, because it's hard to schedule exclusive track time for such things!), cars of wildly different weights and braking hardware stopped within three to six feet of each other from 100 km/h. It's only cars with drums (rears lock too quickly, triggering ABS) and obviously under-specced systems (commercial vans) that took much longer.
 
Would it be possible for PD to implement break failure in the game? Or would that violate the license with car maker since it's part of the car's reliability?
 
HN7
Would it be possible for PD to implement break failure in the game? Or would that violate the license with car maker since it's part of the car's reliability?
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More than likely. Manufacturer licenses are also why you will never see deforming roofs in a video game.

I doubt any manufacturer would like people to know that their expensive carbon-ceramic rotors or their "sports upgrade" cross-drilled rotors can shatter. But I see it possible to simulate brake fade and fluid boiling in the game. It would add a whole new dimension to racing, having to pick a different braking point for cold brakes and another for hot brakes.

Then five or six laps later, if you've been driving like an absolute idiot, no brakes, as the fluid boils over... as it invariably does on most street cars (including sports cars) if you're pushing them to the absolute limit.

But then you'd have to test each car for brake fade, which is very problematic (and difficult). Some experience it after just one or two heavy stops. Others take much longer. Then you take into account environmental conditions such as air temperature, track temperature, humidity, etcetera and the condition of the brakes themselves and whether the pads are bedded in... then if you do your testing wrong, you'll have flat spotted tires, which makes testing even harder... :lol: More likely it'll just be a standard value applied to all road cars and another applied to all racing cars.
 
Toronado
And in some cases, quite dangerous.
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You haven't lived until you've been completely sideways in a three-ton van without airbags, without a crash rating or roll-over protection, and with the outside front starting to dig into the road...




...as a passenger. I threatened to quit after that one. :lol:

The danger is a very real problem. That's why very few publications (Consumer Reports is one, Best Motoring is another) actually do braking and lane-change under braking tests for a wide variety of cars, because even for modern vehicles, it can get nasty (witness the Lexus GX test, where the stability control failed to trigger).
 
niky
You haven't lived until you've been completely sideways in a three-ton van without airbags, without a crash rating or roll-over protection, and with the outside front starting to dig into the road...




...as a passenger. I threatened to quit after that one. :lol:
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I know the feeling, if not the exact circumstances. Scariest moment of my life was when the front suspension of my friends Lumina decided to be mean and tuck under. Suddenly, it was like a gyroscope!

niky
The danger is a very real problem. That's why very few publications (Consumer Reports is one, Best Motoring is another) actually do braking and lane-change under braking tests for a wide variety of cars, because even for modern vehicles, it can get nasty (witness the Lexus GX test, where the stability control failed to trigger).
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Or that Car and Driver 370z test where they had been driving the car perfectly fine (albeit admittedly at a track) when the brakes just randomly went "screw you guys, I'm going home" and acted like someone had cut the lines. I think the driver in that test had to go to the hospital.
 
The scariest part was: We knew what we were doing. We had everything up to temperature, we had a cool-down period between tests, we were on a racetrack straight, and we were all professional (or at least track-experienced) drivers. The vehicle is fine on one test, then on the very next the rears lock up without warning.

Quite similar to that C&D thing... you think you're doing it right, and then... :ouch:

Either way, I've seen way too many instances of fluid boil, even on so-called "performance" cars to trust any stock system past one lap without reservation. Though I have noted that new Nissans tend to experience fade in fewer stops compared to the competition...
 
Very interesting discussion. I wish of would make a test park where we can do all of the basic testing that magazines do. I would love to compare performance of gt5 cars with their real life counterparts.

It would have:

Straight-for top speed, acceleration to various speeds and distances, also to test braking

Slalom

Circle-to test how many turning Gs cars can pull.

Lastly a test track to compare the overall handling and performance of different cars.

It would be fun if we could build our own test park, first pick a region(desert or green fields, then add in the features you want like straights slaloms and circles, then build your own benchmark track and choose the sectors. (mine would have a straightaway, a very technical and maybe hilly section, then high down force turns.)
 
If we have accurate real world figures for 60-0mph stops, and maybe 100-0mph stops, would it be possible to dial in a game car of the same model to give approximately the same value?

Might be interesting to see what the actual figures are for IRL type performance... Even if you don't factor in brake fade or temperature, fluid boil and the like, it would be nice to have the figures one might expect IRL at least as a starting point.
 
Real world figures are available from different publications for various cars. But you have to factor in that you will not always be able to replicate these 100%.

In back to back testing, you can get stopping distances for different drivers that are off several feet. And those differences get even bigger when you factor in ABS versus none, plus brake fade. Personally... if you can get it within ten feet of real life, that's good enough.
 
Very nice thread. I hope stopping distances are not generic with the same tires on different cars.
I should do some testing myself from 100mph to 0.
I felt that I have to brake at different points though while plain racing.
Of course in that case I was approaching the same turns in different cars at vastly different speeds.
 
I don't know, from testing multiple cars at corner 1 at Monza if you don't break loads earlier with a Jensen Interceptor typically you smash head first into the barrier.
 
So have they downgraded braking since GT5 Prologue? That game always gave me problems when I had to brake for the first hairpin on Fuji. When I had learned to master it in an Impreza I would mess up as soon as I went behind the whell of an M3. I haven't spent much time on Fuji in GT5 so I can't tell if there's a difference yet.
 
niky
Weight is an interesting thing. In the one instrumented brake test I've done (and it's the only one, because it's hard to schedule exclusive track time for such things!), cars of wildly different weights and braking hardware stopped within three to six feet of each other from 100 km/h. It's only cars with drums (rears lock too quickly, triggering ABS) and obviously under-specced systems (commercial vans) that took much longer.
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Assuming braking systems that are working and up to the job, then weight itself is a minor factor in regard to stopping distances, the transfer (as you mentioned) is a bigger factor than the weight itself. And despite danjama's 'roll eyes', the track surface/tyre is still the main factor involved

Given identical rubber and assuming all is well with the braking systems, then stopping distances for differing cars should be roughly the same.

Obviously with GT5's 'perfect' conditions, these differences are going to be very minimal indeed.

The following is worth a look in this regard....

https://www.gtplanet.net/forum/showthread.php?t=88533

...figures from an old Auotcar 0-100-0 test, while they look at times rather than distance (which is still valid as they are all times to stop from the same speed - 100mph). It clear that while being wildly different cars, they all have very similar stopping figures. The only road car that stops significantly quicker is the Veyron, which throws an airbrake into the mix.



Regards

Scaff
 
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