what on earth has happened here then?

[Welsh-Fury]

This is my admittedly poor iphone capture of what to me was a strange and surprising game handling/behaviour flaw. The car in question is an Evo, tuned to just around 500pp - so you might fairly imagine that handling would be fairly benign and predictable - but no. Have a look...

I'm staying on topic and went ahead and tested the Evo on the same section of track. I noticed on the video that tam38gti's Evo has very soft suspension in the start of the video when he made his right turn, as well as leaving the ride height of the car unaltered. I'm also noting that these 'stoppies' only happen with this car when going over hills while braking.

The best cure I have for this is to stiffen the suspension 2-3kgf/mm in the front and rear, as well as lowering the car to give it a better center of gravity. While it's still prone to rolling over when hitting a berm, it won't somersault after the start/finish line at Nurburgring, that's if you wish to keep using Racing Softs.


I see everyone trying to connect GT6 to real life, although that is the aim of the physics, GT6's physics is NOT real life and shouldn't be compared as it frequently is. That's why this game is called a real driving simulator.

 

[psavi]

Well ... mass in space doesn't matter, as well as aerodynamics.
As for the video, my opinion is still the same - if you hit something at high speed you will get airborne.

What game is that? It seems pretty unrealistic that crash...

Sorry, off topic.

On topic, this physics problems don't affect me, because I try to use the game within the most realistic boundaries possible. If you for some reason get off the realistic boundaries, you'll get unrealistic results. That's how physics models work.

 

[tam38gti]

I'm staying on topic and went ahead and tested the Evo on the same section of track. I noticed on the video that tam38gti's Evo has very soft suspension in the start of the video when he made his right turn, as well as leaving the ride height of the car unaltered. I'm also noting that these 'stoppies' only happen with this car when going over hills while braking.

Thanks for the comparison! I should add though that the car was lowered about 30mm front and 20mm rear. IIRC

 

[psavi]

I got intrigued with this forward flip phenomenon and decided to investigate further.

I decided to work with the worst possible scenario I could think of. I bought a Fiat 500 1.2 8V, fully tuned power, all weight reduction possible, racing brakes 10:0, fully customizable suspension, 200 kg of ballast in front, LSD, Clutch plate. Everything, except transmission.

In the end I got a car with the following specs:

Weight - 1043 kg (68:32)
Suspension
FSR 2.19 kgf/mm RSR 1.30 kgf/mm
Dampers - 1
Ride Height (front and rear) - 125

Then I took the car to SSRX to see what it would do, the conclusions were as below:

Racing Softs - flip
Racing Mediums - flip
Racing Hards - flip
Sports Soft - flip
Sports Medium - flip
Sports Hard - doesn't flip

So I found the point of grip where it is not possible to flip the car anymore. Then I went to investigate what would happen if I stiffened the suspension to maximum:

FSR - 11,07 kgf/mm RSR 6.01 kgf/mm
Dampers - 10

In those conditions the car would not flip even on Racing Softs.

Then I tried to measure deceleration rates under braking with Racing Softs. Braking from about 160 kph to 0, I collected some points of speed and time, with the help of replay and calculated the average deceleration as about 1.60 g.

Knowing the weight distribution and the wheelbase took from internet (2300 mm), I calculated the longitudinal position of the CG. Then, using simple equilibrium of moments of force, I calculated the maximum CG height for the car not to flip under 1.60 g decelleration, assuming the car had a rigid suspension. It resulted in about 458 mm above the ground.

Now, when braking with soft suspension with Sports Medium, I measured an angle of about 6 degrees just before the rear wheel left the ground. I thought maybe the increase in the CG height caused by the inclination could be responsible for the flip. Approximating the increase as tangent of 6 degrees times the CG distance to the front axle, I calculated that I would need a deceleration of 1.375 g to flip the car. The average deceleration from 157 kph to 99 kph - the speed the rear wheels started to leave the ground - was 1.284 g, below what was needed. However, if I took only the 4 last points before the wheels leave the ground, I have an average deceleration of about 1.375 g.

I hope I was clear enough for people understand. If someone will be interested, I can detail more my calculations.

To conclude, I know my calculations have a lot of approximations and assumptions but it is what I could do. It doesn't prove anything, but it gives me more reason to believe that the problem is not gravity, but inaccurate system responses when the inputs are outside the system's accurate interval.

In my experiments, I realized the system behaves in somewhat different ways before and after the wheels lift the ground. I guess it is too hard to model all the different scenarios at once.

So before you put Racing Softs on a car, think about stiffening the suspension.

 

[Griffith500]

Bravo sir, excellent stuff! 👍

 

[brianwong]

However unrealistic the tires are though, the gravity in the game is still very wonky.

 

[jr93alty]

The game tells you what the tires are supposed to represent! There is a description for each variety of tire when you go to the tuning shop and the one for comfort tires describes them as being the best representation of real world road tires. Furthermore, PD uses a photo next to the tire types as further description, with the one next to comfort tires depicting a street radial, the one next to sports tires depicting a cup tire, and the one next to racing tires showing a true slick tire. Whether or not PD has accurately modeled each tire type is open for debate, but it is incredibly obvious what each type is supposed to represent.

You say, "how do we know?", that we're making this stuff up? I say, how on earth do people stumble through the game so blindly not noticing things like the images next to the tire selections? If a sports tire is not a cup tire why do PD show a picture of a cup tire? If a comfort tire is not supposed to be a street radial why do they show a picture of one of them next to them? It's obvious!

So your answer is that there is a picture and I somehow didn't notice that? My point is that "real world road tires" means nothing. The range of OEM tires in the world is huge even amongst family sedans. Not to mention that my point is that people argue of SS versus SH which is what I considered pointless and funny. I've known plenty of people that leave drag radials on their car no matter where they drive it (if it isn't their everyday driver). For people where money is no issue, I'd imagine it wouldn't matter if they did drive it every day. I still say that describing something as a "cup tire" or "racing slick" means almost nothing except to vaguely described a tire so I'll say again that it's comical when people argue over stupid variances between a generic group of tires based on how much grip they think a car should have. They have rim manufacturers...they should just use real tires so it means something although I know they won't do that because that leaves them open for liability because money would be riding on these poor physics. I know that in old GT's, car manufacturers use to pay to have their car in the game...if they still do that, I'm surprised car companies aren't upset at the physics of some cars because people use to attribute a fair number of car sales to the GT series.

 

[psavi]

So your answer is that there is a picture and I somehow didn't notice that? My point is that "real world road tires" means nothing. The range of OEM tires in the world is huge even amongst family sedans. Not to mention that my point is that people argue of SS versus SH which is what I considered pointless and funny. I've known plenty of people that leave drag radials on their car no matter where they drive it (if it isn't their everyday driver). For people where money is no issue, I'd imagine it wouldn't matter if they did drive it every day. I still say that describing something as a "cup tire" or "racing slick" means almost nothing except to vaguely described a tire so I'll say again that it's comical when people argue over stupid variances between a generic group of tires based on how much grip they think a car should have. They have rim manufacturers...they should just use real tires so it means something although I know they won't do that because that leaves them open for liability because money would be riding on these poor physics. I know that in old GT's, car manufacturers use to pay to have their car in the game...if they still do that, I'm surprised car companies aren't upset at the physics of some cars because people use to attribute a fair number of car sales to the GT series.

 

[moron88]

Not under normal circumstances..
You must bang really hard to make the car flip in GT5.

pick a miata, any miata. slap race softs on and give it a some more HP. now take a corner at a decent clip and watch it roll.

 

[CAMAROBOY69]

Since I have recently rented GT6 and have put some time into it, I have FINALLY run into this problem. It didn't happen until I purchased "Racing Soft" tires. And yes it is indeed frustrating. Coming up to a corner flat out, hit the brakes, rear tires lift and I spin out of control. Online this is beyond frustrating and I seen it happen with many other people. It was happening with my AWD Evo and AWD GTR. After messing around with a few features that involve physics, I fixed the problem!

Long story short after lots of trial and error, I simply swapped the front tires to "Racing Medium" and I leave the rear tires "Racing Soft". Out of everything else I tried, this instantly worked for me. Hope it helps the rest of you with this problem.

 

[vkmaxx]

It can happen:

 

[noseknows36]

It can happen:

If someone could replicate this in GT6 you would be considered a god

 

[Sander 001]

It can happen:

That video doesn't show a full frontal flip. Did you post the wrong youtube clip?

 

[Whitestar]

It can happen:

HOLY *****! That looks supernatural! It's like he's thinking: "Ok that just happened. Now how fast can I go without tipping over?".
Doesn't seem to care that most of his car is airborne, just wants to keep that red car behind him. Hahah, amazing!

 

[SZRT Ice]

It can happen:

For the motha' lovin' win... Phenomenal.

That video doesn't show a full frontal flip. Did you post the wrong youtube clip?

He may have been responding to this post:

For sure there is something wrong with gravity in GT6.

Never saw a car go UP again after touching 4 wheels on the ground.

And the subsequent posts that followed...