How close to real life is the steering forces we have in iRacing?

[MacIntyre]

I have always thought that there is something wrong with the forces we get in the steering wheel in iRacing. They are most of the times way too strong and overall unbalanced, especially when you hit a curb, the peaks have always felt way too strong as well as the force required to turn the wheel.
When you look at the telemetry in iRacing it shows forces up to around 60Nm for a GT3 car and up to 120Nm for the Dallara DW12.
To be able to get such numbers we would need a wheel base that puts out 60Nm to get a 1:1 ratio for a GT3 car and 120Nm for the Dallara DW12.
When I put my SC2 Pro at a 1:1 for the MX-5 it’s hard to turn the wheel when I drive, I don’t have that issue in the real car.
If we now put those numbers in some real life perspective, a broken power steering takes a lot of effort to turn even when the car is moving and that is around 40+Nm. Now imagen that you would need 20Nm more to get a 1:1 ratio for the GT3. I have always question those numbers in iRacing. There is no way those numbers are based on real life data.

I finally found some real life data for the Dallara DW12 at Long Beach so we can compare it with iRacing.
iRacings telemetry peaks at around 110Nm at Long Beach on the inside curb at T9 and around 30-40Nm in the corners.
The real peaks at around 27-28Nm on the inside curb in T9 and 15-20Nm in the corners and that is for a car without power steering.
What does it means for us, as we can see the SC2 Pro can handle the corner forces and 90% of the peaks of the real car with its output of 25Nm.
iRacing peaks 2 times more in the corners and 4 times more at the curb strike in T9 compared to the real car.
To get the corner forces close to real we should not use more than a specific output ratio of 0.500 for the Dallara DW12, but that means we still have 2 times as much curb forces as we should have.
If we setup the wheel with 0.500 specific output ratio we still get a lot of clipping because of the 4 times higher peaks at the curb strike in T9.
If we then setup the wheel to handle the peaks and clipping correctly (around 0.233 specific output for curb strikes) we don’t get the right corner forces.
Considering the numbers we get for the Dallara DW 12 and the GT3 cars (around 60Nm), I guess we have the same wrong numbers for all cars in iRacing. No wonder why so many real life drivers say it feels best and closer to real life at a specific output ratio of 0.300-0.500.
This is the reason why I want a tool like an equaliser so we can affect the signal and balance the forces instead of just damping everything.

Until iRacing fix this or we get the proper tools we will never be able get a true 1:1 ratio.
When and if they do, we don’t need a 60Nm monster wheel base to get a true 1:1 for a GT3 car or 120Nm for the Dallara DW 12. We already have a wheel base capable of handling all corner forces and 90% of the peaks we have in the real Dallara DW12. Which I believe has one of the strongest steering forces in iRacing. The output numbers we have in iRacing are just wrong and way too strong.
iRacing telemetry.

Real car telemetry. The green graph is for the Dallara DW12.

[Marty]

Very interesting reading. Thanks for taking the time to write this. Interested to see some answers.

[MacIntyre]

Thanks
There is also one more thing we need to take into consideration, the acceleration speed of the wheel.
In the real car based on the picture I would say it takes around 0.2 sec to go from 0-28Nm, It’s hard to tell from the picture.
Real car.

In iRacing it takes around 0.05 sec if you look at the pictures, I know we are not at 0Nm in the pictures, but it’s still around 4 times faster. (time between the 2 yellow lines)
iRacing

[MacIntyre]

@Mika What would be the right value for the Slew rate limiter to get the speed right?

[Alfye20]

Im not Mika, but I use very low Slew Rate on my profiles to feel something more real on mi “low” powered SC2 Sport.
SLR of 0.12 for a 1.5kg formula wheel and 0.94 for +2kg 30cm round wheel.
It depends on how much servo Damping friction and inertia are in use, mine are below 5% in all profiles

[MacIntyre]

I guess you are setting the SLR after you have tuned in Damping, Friction and Inertia.
I try to do it the other way around, getting the forces balanced (Torque bandwidth limit and recon filter) and the speed right to minimize the use of damping, friction and inertia, and use them to get the right behavior in the wheel rather then using them for balance the forces.
If that is the right or wrong way to do it, I don’t know?
If there is something like the right or wrong way when the forces are wrong from the beginning

[Alfye20]

I do it like you do, I have a base profile with Overall Force, Recon, Torque Band and UltraLowLatency, all rte same for all my wheels.
Then tune up SRL to match the wheel weight and finally fine tune with Servo constant filters to find the perfect balance…
+3years with SC2 and still tuning … XD
Im as low as 0.5% on Servo Damping loading modified profile.ini archives

[MacIntyre]

Phew, glad to here that someone else using that approach
The issue starts already in the signal but if that has to do with the update rate I don’t know.
On-top of that we have the effect different wheel sizes and weight has, makes it even harder to tune in the SRL correct.
I have tried all settings there is in the App.ini not only the damping.
8+ years with SC and still tuning

[Alfye20]

@MacIntyre

I have tried all settings there is in the App.ini not only the damping

When I talked about profile.ini, it is about True Drive custom profiles like this, you can load it and find more granularity on servo constant filters:

@MacIntyre

The issue starts already in the signal

What about iR app.ini steeringFFbsmooth ? Didi you tried it?

[CLAYREGAZZONI]

As I don’t have any experience with Iracing my question is:
Isn’t it possible to just turn down torque/force in either TD or Iracing, or both to get the correct amount of torque/force? And is this something Iracing related only?

[Alfye20]

Linear forces on iRacing is a different beast VS other sims.
You can go from 0 to full torque instantly, so too low forces on wheel or game can break the linearity, giving you no useful forces on low speed corners if you whant a comfy feeling on hi loaded turns

[MacIntyre]

I didn’t know about that profile.ini, I will defiantly have a look at it. Where do I find it?
In IR app.ini I have tried all settings under the force feedback section. Some of them have no effect on a DD wheel and some makes it worse.

[Alfye20]

@MacIntyre

Where do I find it?

There was an Export profile button in older True Drive versions, then you can edit and import.
If you dont have any, feel free to copy this like a new “profile.ini” file:

[Simucube2_Profiles_V2]
Profile1\name=Fine Tune
Profile1\dxsinegain=0
Profile1\dxsquaregain=0
Profile1\overallstrength=64
Profile1\dxspringgain=0
Profile1\dxfrictiongain=0
Profile1\dxdampinggain=0
Profile1\dxinertiagain=0
Profile1\bumbstoprange=0
Profile1\servo_torquebandwidth=9
Profile1\servo_peakingnotchfilter=0
Profile1\servo_damping=5
Profile1\servo_friction=21
Profile1\servo_inertia=22
Profile1\servo_reconfilter1=4
Profile1\filteringModes=0
Profile1\dxsawtoothgain=0
Profile1\dxtrianglegain=0
Profile1\steeringrange=1090
Profile1\staticforcereduction=0
Profile1\ultralowlatency=10
Profile1\slewratelimit=120
Profile1\staticforcereductionspeed=1000
Profile1\gamma=1000
Profile1\centerdamping=0
Profile1\centerdampinganglespan=0
Profile1\simplesettings=66368
Profile1\uibits=0
Profile1\varioussettings=1
Profile1\bumbstop=2

Then click on “Import settings of a classic profile from .ini file” button

Servo Damping Friction and Inertia values goes from 0 (0.0%) to 1000 (100%)

[MacIntyre]

Thank you so much

[Alfye20]

Let the test restarts!!!

EDIT

@MacIntyre

In IR app.ini I have tried all settings under the force feedback section.

I found SteeringFFbSmooth realy useful and seeing your test result VS real car, I found that im at 25% of iR current force with a value of 0.25 on that line, and coincidentally matches your findings

[MacIntyre]

Interesting, is that for the corner forces or the curb peaks?

[Alfye20]

It is more noticeable on the responsiveness of the forces.
Start from 0.1 then 0.15, 0.2, 0.25…
From 0 to 0.2 i can feel lag/latency

[CLAYREGAZZONI]

Thanks a lot!! You are always very kind and nice. Is a pleasure

[bsohn]

There is ONE MAJOR factor missing here and it is something that you don’t have in the data you have provided and that is the set-up…

If you are using the baseline setup or one based on the Baseline set-up for the DW12 then it is generally using an 8tooth steering pinion…

From conversations with Real world Indy Car drivers they will use ONLY the 6tooth pinion on the real car as otherwise you get extraordinary forces like what you are seeing… When using the 6 tooth pinion with the DW12 you should see Steering output numbers MUCH closer to the real numbers of the car output… As well setup in general caster angle, Camber, Toe, etc can also cause difference in output through the steering column.

I have seen data from Barber Motorsports Park that with the same setup on the DW12 the Steering torque graphs aligned almost identically. ecxept for a few outliers… Unfortunately I am not at liberty to show this data as it is not mine to show AND Yes it could be a little out of date given the newer iRacing Tire Model Data as it was early in the DW12, so before the IR18…

The DW12 though with the 8 tooth pinion will Spike VERY VERY high in torque due to its quicker steering ratio. I think Iracing settled on thins in regard to their baseline set-ups due to that higher torque output translates well to less powerful wheels by giving more active indication of the amount of torque.

I racing smoothing setting in the app.ini is much like the Reconstruction filter in a way but done on the telemetry feed… It can be useful to create a smoother output from the game but it comes at a cost as it must do additional processing before being output as a % to the device.

The interesting thing is that the close you get to your the wheel being natural in feel the spikiness will come closer to that of the real cars line as the changes you make in the wheel will allow you to control the wheel movement (eliminating the spikes) and therefore be closer to the real output…

@CLAYREGAZZONI - With regard to force from iRacing you would increase the MAX force in iRacing but with the DW12 IF you are getting 120NM spikes you would need a much higher number to not be beat up still as the telemetry coming from the game doesn’t really change (other than with Set-up of the car)… SO TD would be the place to reduce the force for this particular car.

I would be curious for you to try the settings I have for the SC2 Pro along with the set-up with a 6 tooth pinion in the DW12 set-up to see how close they fall… Granted the other suspension set-up issues would be different but the 6 tooth is the MAJOR factor difference in all the DW12 Road Settings.

For me the car is fully drivable with the MAX Force at 42Nm (.595:1) but Because the DW12 is a beast I usually will end up with at the wheel force of about 60 Max force or .417:1 because at .595 I struggle to make it through a race.

[MacIntyre]

With the 6 tooth pinion, it had a massive impact on the high spikes dropped from 120Nm down to around 60Nm but for the corner forces not so much. They are still around twice as high as the real car. The graph is with the HDF iRacing setup the same I used in the first picture, the only change I made was the steering pinion.

It would be interesting if had more real data for other cars as well.