Observations on suspension settings
- Thread starter Stotty
- 611 comments
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- 3,359
- California
- PumpinNumbies
I'm not going to disagree, but one aspect confuses me...
You claim that the front and rear are reversed in the menu's, but then follow to say that replays show the front of the car in the air, with the rear slammed, correct?
By my logic (which may be flawed) this means that the game is still translating the front as the front and the rear as the rear. At least visually.
This would mean the claim that the menu is reversed, only applies to the physics side of the equation, not to the visual side.
I feel the easiest way to prove or disprove this theory would be drag racing.
Obviously drag cars are set up with a very specific theory in mind.
Take your drag tune, reverse it and re-test.
The difference between the 2 polar opposites should be rather extreme for straight line acceleration.
This should provide a strong arguing point for or against the theory, based on the results.
Any Drag Tuners?
You claim that the front and rear are reversed in the menu's, but then follow to say that replays show the front of the car in the air, with the rear slammed, correct?
By my logic (which may be flawed) this means that the game is still translating the front as the front and the rear as the rear. At least visually.
This would mean the claim that the menu is reversed, only applies to the physics side of the equation, not to the visual side.
I feel the easiest way to prove or disprove this theory would be drag racing.
Obviously drag cars are set up with a very specific theory in mind.
Take your drag tune, reverse it and re-test.
The difference between the 2 polar opposites should be rather extreme for straight line acceleration.
This should provide a strong arguing point for or against the theory, based on the results.
Any Drag Tuners?
- 3,180
- USA
- GTP_CarlosF
I think that's exactly what's being said - it affects the graphics one way and the physics the opposite way. Have yet to really play with it in the extreme to satisfy my own curiosity though.
- 1,139
- budious
So you are saying the rake angle transfers weight in the opposite direction as expected, but not necessarily that the ride height relationship to spring rate is wrong? I'll have to take a look at that...
As for the ride height itself, I'm quite convinced that it is an extension of suspension travel in addition to a physical ride height change in the car. I've noted in the past where a car will handle as though a +5 addition of ride height equates to a %5 increase in suspension stiffness. You can find an example of the formulas demonstrating this possible relationship in the OTI post in my signature, just scroll down to the bottom and look at example 2-A regarding the MR2 '86 NA and MR2'86 Super Charged tuning and handling comparison.
In your case, by my finding, +15/-30 would result in a car with 15% stiffer front and 30% softer rear in effect to the given kgf/mm measurement, assuming an example with the game's stock motion ratio. That would result in a FR car having softer rear end and thus better traction and stronger steering at the front, then also consider any weight transfer in rake angle, but I'm not sure how specific or accurate the game's physics are in that regard, as you have pointed out as a possible issue here.
As for the ride height itself, I'm quite convinced that it is an extension of suspension travel in addition to a physical ride height change in the car. I've noted in the past where a car will handle as though a +5 addition of ride height equates to a %5 increase in suspension stiffness. You can find an example of the formulas demonstrating this possible relationship in the OTI post in my signature, just scroll down to the bottom and look at example 2-A regarding the MR2 '86 NA and MR2'86 Super Charged tuning and handling comparison.
In your case, by my finding, +15/-30 would result in a car with 15% stiffer front and 30% softer rear in effect to the given kgf/mm measurement, assuming an example with the game's stock motion ratio. That would result in a FR car having softer rear end and thus better traction and stronger steering at the front, then also consider any weight transfer in rake angle, but I'm not sure how specific or accurate the game's physics are in that regard, as you have pointed out as a possible issue here.
- 8,642
- London
- GTP_Stotty
What I'm saying is this...
If you change the front ride height to max and the rear to min, the car displays this visually when you look at the replay, but the car behaves as if the front was min height and the rear max.
The game could be modelling spring rates relative to both the absolute setting and the amount of travel, but I'm not sure how you'd work the exact percentage change without knowing the amount of suspension travel before you made any changes.
If you change the front ride height to max and the rear to min, the car displays this visually when you look at the replay, but the car behaves as if the front was min height and the rear max.
The game could be modelling spring rates relative to both the absolute setting and the amount of travel, but I'm not sure how you'd work the exact percentage change without knowing the amount of suspension travel before you made any changes.
- 77
- Finland
- Zkippe
This has been bugging me as well since the first time trials when I first learned about the benefits of the "high front/low rear" -setup. I've come to the conclusion that weight distribution is the most important thing that affects any car's behaviour. I don't think there are any errors in the settings menu itself like people have been suggesting (front/rear mixed up etc.). The front settings affect the front of the car and the rear settings affect the rear, both visually and physically. It's just that the physics engine in the game doesn't seem to work exactly the same way as for example in some pc-sims (and in real world?).
In theory softer suspension should give more grip than a stiff one: friction, or grip, is dependent on the area of the contact patch, contacting materials and the load on the contact patch (probably some other stuff as well, but these are the basic ones). This doesn't seem to be true in GT5. Instead, the more load a tyre has, the more easily it will lose traction.
I'll give an example: try any older RR car first with stock settings (I've tested with a RUF BTR and a fully tuned 60s Fiat 500). The car is very oversteery because most of the weight is on the rear axle. Now set front ride height to the min and rear to the max. Also soften front and stiffen rear. You can even add ballast to the front. The car is now much more stable, if not even understeery. What you did was transfer a lot of the weight towards the front in a previously rear-heavy car. Now the load on tyres during corners is more even than before and the car is more balanced. But in theory it should be the exact opposite, shouldn't it?
I've no experience in real life racing, so I'm just guessing and trying to figure out why the game works the way it does. And I've come to this conclusion that distribution of weight is the dominant factor in setup, but added load on a tyre doesn't mean added grip and that's why it seems the settings work in the exact opposite way than they should.
In theory softer suspension should give more grip than a stiff one: friction, or grip, is dependent on the area of the contact patch, contacting materials and the load on the contact patch (probably some other stuff as well, but these are the basic ones). This doesn't seem to be true in GT5. Instead, the more load a tyre has, the more easily it will lose traction.
I'll give an example: try any older RR car first with stock settings (I've tested with a RUF BTR and a fully tuned 60s Fiat 500). The car is very oversteery because most of the weight is on the rear axle. Now set front ride height to the min and rear to the max. Also soften front and stiffen rear. You can even add ballast to the front. The car is now much more stable, if not even understeery. What you did was transfer a lot of the weight towards the front in a previously rear-heavy car. Now the load on tyres during corners is more even than before and the car is more balanced. But in theory it should be the exact opposite, shouldn't it?
I've no experience in real life racing, so I'm just guessing and trying to figure out why the game works the way it does. And I've come to this conclusion that distribution of weight is the dominant factor in setup, but added load on a tyre doesn't mean added grip and that's why it seems the settings work in the exact opposite way than they should.
- 15,854
- QLD, Australia
- Small_Fryz
From many hours testing I have came to the exact same conclusion as Stotty.
The most dramatic effect can be seen in FF or 4WD cars. The only issue I found with having too much discrepancy between front and rear ride height was the cars tendency to snap oversteer mid corner on the power. This can be somewhat tuned out by use of the springs or toe, but in general I found that each car has its own "sweet" spot for how different you run the ride height. Some cars only need a difference of 5 - 10, while others can run a difference of 20 - 30. I also blame the lack of real values in GT5's tunning but rather the made up numbers. This leads me to believe that a spring rate of "10" on a street car is not equal to a spring rate of "10" on a race car in terms of stiffness or force. All this adds upto a lot of inconsistencies in tunning.
All in all, my advice in GT5 tunning is to throw any concept of "real world" out the door and simply just adjust based on your feel and reaction.
The most dramatic effect can be seen in FF or 4WD cars. The only issue I found with having too much discrepancy between front and rear ride height was the cars tendency to snap oversteer mid corner on the power. This can be somewhat tuned out by use of the springs or toe, but in general I found that each car has its own "sweet" spot for how different you run the ride height. Some cars only need a difference of 5 - 10, while others can run a difference of 20 - 30. I also blame the lack of real values in GT5's tunning but rather the made up numbers. This leads me to believe that a spring rate of "10" on a street car is not equal to a spring rate of "10" on a race car in terms of stiffness or force. All this adds upto a lot of inconsistencies in tunning.
All in all, my advice in GT5 tunning is to throw any concept of "real world" out the door and simply just adjust based on your feel and reaction.
- 8,642
- London
- GTP_Stotty
If it was as simple as soft is best you wouldn't see real life race cars running super hard suspension 
With soft suspension comes body roll, and this negatively affects suspension geometry, adding or subtracting camber. Race cars suspension is stiff and has a short travel to beter control the tyre contact patch and to minimise weight transfer. The objective is having the suspension move in a very controlled operating range... it's much easier to tune race car suspension than road car susspension as ride quality doesn't really need to be considered.
I suspect one of the key reasons stiff suspension works so well on GT5 (along with accurate camber tuning) is because the physics engine is using some sort of tyre contact patch model as the key driver of lateral grip.
Anyhow to get back to the general though of the settings being transposed in the menu...
One of the things that's always bugged me about GT5 physics is this...
I'm braking in to a turn (trail braking) and the front of the car is nailed to the line I want, as I get close to the apex I ease off the brake to allow the car to coast a while... but as soon as I release the brake the car starts to run wide of the line I was on.
What's happening here is as soon as I release the brake I get weight transfer towards the rear of the car, unloading the front tyres and causing understeer.
Now this just doesn't happen in real life unless you're driving something with a very rear baised weight distribution (such as a 911). Yes, weight will transfer off the front tyres as you bleed away brake pressure, but the rate of transfer should be so minimal that it is not sufficient to cause significant understeer.
The way to fix this understeer should be one or more of the following... all with the objective of reducing weight transfer away from the front tyres.
1. Lower the front ride height
2. Raise the rear ride height
3. Lower front re-bound damping
4. Increase rear spring rates
5. increase rear compression damping
But none of these work consistently.
What does work is raising the front ride height or lowering the rear... which is totally contradictory!
There's something amiss with the way the settings transfer in to the handling of the car. Of course this might not be front/rear settings being reversed, it could just be that PD have modelled it this way. But to me (and to some others), the settings do work in reverse.
When do you see a car (road or race) with nose up stance? You don't. But you see plenty with a slight nose down stance!
Absolutely, Dion. Spring rates/ranges are not consistent across different cars 👍
And I agree you should tune what you feel, but it's nice to have a starting point to tune from... and historically in GT games, you'd have just slammed the front and rear when tuning and then raised the rear until the understeer was reduced.
What I'm saying now is you should slam them both, but then raise the front until the understeer goes away... which just isn't right.
With soft suspension comes body roll, and this negatively affects suspension geometry, adding or subtracting camber. Race cars suspension is stiff and has a short travel to beter control the tyre contact patch and to minimise weight transfer. The objective is having the suspension move in a very controlled operating range... it's much easier to tune race car suspension than road car susspension as ride quality doesn't really need to be considered.
I suspect one of the key reasons stiff suspension works so well on GT5 (along with accurate camber tuning) is because the physics engine is using some sort of tyre contact patch model as the key driver of lateral grip.
Anyhow to get back to the general though of the settings being transposed in the menu...
One of the things that's always bugged me about GT5 physics is this...
I'm braking in to a turn (trail braking) and the front of the car is nailed to the line I want, as I get close to the apex I ease off the brake to allow the car to coast a while... but as soon as I release the brake the car starts to run wide of the line I was on.
What's happening here is as soon as I release the brake I get weight transfer towards the rear of the car, unloading the front tyres and causing understeer.
Now this just doesn't happen in real life unless you're driving something with a very rear baised weight distribution (such as a 911). Yes, weight will transfer off the front tyres as you bleed away brake pressure, but the rate of transfer should be so minimal that it is not sufficient to cause significant understeer.
The way to fix this understeer should be one or more of the following... all with the objective of reducing weight transfer away from the front tyres.
1. Lower the front ride height
2. Raise the rear ride height
3. Lower front re-bound damping
4. Increase rear spring rates
5. increase rear compression damping
But none of these work consistently.
What does work is raising the front ride height or lowering the rear... which is totally contradictory!
There's something amiss with the way the settings transfer in to the handling of the car. Of course this might not be front/rear settings being reversed, it could just be that PD have modelled it this way. But to me (and to some others), the settings do work in reverse.
When do you see a car (road or race) with nose up stance? You don't. But you see plenty with a slight nose down stance!
Absolutely, Dion. Spring rates/ranges are not consistent across different cars 👍
And I agree you should tune what you feel, but it's nice to have a starting point to tune from... and historically in GT games, you'd have just slammed the front and rear when tuning and then raised the rear until the understeer was reduced.
What I'm saying now is you should slam them both, but then raise the front until the understeer goes away... which just isn't right.
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- 1,929
- Show Me State
- Stroker-Z28
That hits the nail on the head 👍
You can't go by any "real world", or "what should work", theories when tunning a car in GT5. All you can do is try things until somethings works for you, and that may or may not work for the next car you try to tune.
I think people keep trying to treat GT5 as a racing "sim", and expect things to work like they should. GT5 is not a sim, it's a game, it can be a lot of fun if you don't expect it to be more than it is. I enjoy it for this very reason, I can play GT5 with my friends who are not into sims and all the time and practice they entail. If I want "real world", I'll get on my pc and race with a racing simulator.
- 8,642
- London
- GTP_Stotty
Hmmmm, whether the physics are accurate or not, we should be able to identify some basic tuning principals to help create a base tune for cars... I doubt PD have a different engine modelled for each car.
Approaches like low front high rear have always worked in previous generations of the game, whatever the car.
eclipsee
Premium
- 796
- Spain
- eclipsi_RC
Chris, I think you're right about the swapped suspension settings as well, I'm not sure about springs but I'm sure dampers are swapped.
The problem is what you set in the height ride car settings menu is swapped in the car physics, what there say is the front in fact is the rear side and vice-versa (always speaking about car physics), by another side, the link between the values you put there and how you see the car in the replay is correct though.
Yep, as you set them in the menu.
Yep.Adrenaline
Yep.Adrenaline
The problem is what you set in the height ride car settings menu is swapped in the car physics, what there say is the front in fact is the rear side and vice-versa (always speaking about car physics), by another side, the link between the values you put there and how you see the car in the replay is correct though.
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- 2,898
- London
- GTP_Synwraith
I've not experimented with ride height at all really but I agree completely with what Chris has said about the suspension. I run almost every car straight off the showroom floor with maximum spring, damper and anti roll bar settings, and it affords me excellent handling and grip characteristics, as well laptime, compared to soft or stock.
And why did I not mess with ride height? Because every time I tried to lower a car I ruined it in some way, so this sheds a lot of light on this. I remember Ramon suggesting this in WRS week 1, and I can definitely relate to what Chris has said.
Thank you for expressing it in such a clear and accessible way, Chris 👍
All the best
Maz
And why did I not mess with ride height? Because every time I tried to lower a car I ruined it in some way, so this sheds a lot of light on this. I remember Ramon suggesting this in WRS week 1, and I can definitely relate to what Chris has said.
Thank you for expressing it in such a clear and accessible way, Chris 👍
All the best
Maz
- 4,455
- Teesdale
- GTP_Vagabond
I think some specific car suspension settings themselves support what Chris is talking about. For example, the Ferrari F430, you can lower the rear but not the front... this doesn't make sense. Similar thing with the Audi R10 LMP - the front can be lowered to -15 and the rear to -35, which again would not make sense particularly in an LMP car where rake = downforce, not just weight distribution.
- 3,180
- USA
- GTP_CarlosF
Remember though that LMP cars have massive fuel tanks so I'd understand IRL if they would jack up the back for the race and keep it low for qualy... Race cars are also more sensitive to front ride height in respect to downforce, so I could understand why a minimal window of adjustment would be available.
It's all a guess though isn't it about how detailed the physics modelling is for each car. I think someone felt a large difference between the same brands of stock car last week?
The Outlaw
Premium
- 3,042
- Bay Area, California
- GTP_timeattack
Imo, a lot of this has to do with the front suspension seeming to bottom out much too easily (or it could possibly be some issue with the tire model). That's why I believe the hard springs and higher front ride height (reverse rake) seem to cure the understeer (particularly during entry to apex) that a lot of cars have when you drop them too low, or run too soft of a spring rate. Also, I find it important to dial in the spring rate and ride height for each particular track, as a super stiff spring rate isn't ideal on a lot bumpy tracks (something which is expected in reality), or tracks where you can use a lot of curb to gain time.
Just my 2 cents on the subject
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- 734
- osrg/GTP_osrg
- oosrg
To all that have contributed to this thread, from Stotty's original post to the observations from Ramon, Carlos, Sid, Maz and others......
I for one appreciate the science in your thoughts, this for me is one of the best threads on GTP for a very long time.
Now I know obviously I'm a Division 1 steerer, but i just get in and drive, and when the tuning side comes to play I generally just grab someone's tune and have a play with ride height and camber, as i really have no idea on the science of suspension/differentials/gearing etc etc..... So to have a detailed process of the why's, how's, the do's and dont's is a great help to me personally for when I do get time to set a tune up for myself.
Again, the points and thoughts laid out here through your own tests are greatly appreciated guys....
I for one appreciate the science in your thoughts, this for me is one of the best threads on GTP for a very long time.
Now I know obviously I'm a Division 1 steerer, but i just get in and drive, and when the tuning side comes to play I generally just grab someone's tune and have a play with ride height and camber, as i really have no idea on the science of suspension/differentials/gearing etc etc..... So to have a detailed process of the why's, how's, the do's and dont's is a great help to me personally for when I do get time to set a tune up for myself.
Again, the points and thoughts laid out here through your own tests are greatly appreciated guys....
- 8,642
- London
- GTP_Stotty
The hardest part of tuning, IMO, is that to understand if your changes are working, you need to be able to run consistently close to your limit for lap after lap after lap. And I think that's where most people struggle... they don't have the consitency to run at 95-99% of their potential for long periods of time.
If you can do this, then it's realtively easy to see if the changes you made are having the desired effect.
Personally, I don't think of myself as being a good tuner. Although I have a good amount of scientific understanding of how the settings should affect the car, I don't have a huge amount of time to spend playing GT5 (due to work and other social commitments) and I struggle to know where to start when settng up a car from scratch. What I can do however, is take a decent base tune and refine it effectively.
Part of the settings challenge in GT5 is forgetting some of the things you know to be true in real life... because they don't work the same in the game!!
If you can do this, then it's realtively easy to see if the changes you made are having the desired effect.
Personally, I don't think of myself as being a good tuner. Although I have a good amount of scientific understanding of how the settings should affect the car, I don't have a huge amount of time to spend playing GT5 (due to work and other social commitments) and I struggle to know where to start when settng up a car from scratch. What I can do however, is take a decent base tune and refine it effectively.
Part of the settings challenge in GT5 is forgetting some of the things you know to be true in real life... because they don't work the same in the game!!
eclipsee
Premium
- 796
- Spain
- eclipsi_RC
IMO, camber angle and toe are definitively right.
I've some doubts about springs and anti roll bars yet but Chris' theory makes sense, PD could have swapped the suspension menu columns.
My knowledge about mechanics is poor, I know what some parts of the car affect its handling in real life but my basis is not strong, so I tweak my car settings by feeling.
I think the key for good car settings is to get the balance right, what you tweak on the rear side will affect the front side and vice-versa, no matter what car part are you tweaking.
Anyway GT5 car settings are a bit of ********, Rudi and me made opposite car settings in WRS#1 and we got almost the same times, once you get some decent car settings refine your lap and push, you shouldn't lose more than half second from the top in most cases.
BTW, when I say "get the balance right" I mean this too.
I've some doubts about springs and anti roll bars yet but Chris' theory makes sense, PD could have swapped the suspension menu columns.
My knowledge about mechanics is poor, I know what some parts of the car affect its handling in real life but my basis is not strong, so I tweak my car settings by feeling.
I think the key for good car settings is to get the balance right, what you tweak on the rear side will affect the front side and vice-versa, no matter what car part are you tweaking.
Anyway GT5 car settings are a bit of ********, Rudi and me made opposite car settings in WRS#1 and we got almost the same times, once you get some decent car settings refine your lap and push, you shouldn't lose more than half second from the top in most cases.
BTW, when I say "get the balance right" I mean this too.
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chuyler1
Premium
- 4,548
- New Hampshire
- chuyler1
Very interesting thread. I typically run the same height front and rear, and usually the same damper settings front and rear. I've tuned out most understeer with the rollbars and tweaks to toe. I guess my tuning style is why this bug has eluded me for so long.
- 2,898
- London
- GTP_Synwraith
- 5,303
- Riverside, Ca
- GTP_Leonidae_MFT
Wouldn't a rallycar or such be ideal for researching this? They have plenty of suspension travel, thus, they should also display the changes more clearly.
- 379
- GTP_Sidplayos2
eclipsee
Premium
- 796
- Spain
- eclipsi_RC
Hey, you're spicy!I guess that's because "People are People"
I'm glad to know we're in the same ship. 
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