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Thank You, rake is a good idea.
What is the difference variation between front and rear, if the rake is 1-3 degrees. The length of the car is 4.240mm?
Jouni

Hi Jouni,

The length you want to consider is the wheelbase i.e. front strut to rear strut distance.

From carfolio:
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wheelbase = 2570 mm

then to get the front and rear ride height difference (assuming the RH is measured at each suspension strut), you can draw a triangle where the wheelbase is the hypotenuse, the difference in ride height is the opposite. Call the rake angle A. Then you have:

sin A = opp/hyp

hyp * sin A = opp

2570 mm * sin (2 degrees) = opp = 89.7 mm i.e 90 mm

by the same method, 4 degrees rake gives a whopping 179 mm difference!!!

This method obviously makes assumptions about how GT6 measures things and assumes that it uses the same wheelbase data etc!

Easy enough to set up calculations for this in a MS excel sheet if you want to check out lots of values. Some versions of excel only accept angles in radians into the trig functions, I had to convert deg to rad: rad = deg * 2 * pi /360.

EDIT: It's my belief (but I can't prove it as I didn't code GT6!) that differences in ride height will affect caster, leading to odd handling effects, the "ride height bug". If you run a lot of rake (front low/rear high), you may be able to run a little more front camber, as you've effectively used less caster which means you will gain less camber when steering. Likewise, from earlier discussions (OdeFinn wrote this first I believe), caster effectively converts initial neg camber to toe in when steering, hence the "use neg camber but put toe out" tactic; the toe out counteracts the toe in you create when steering.

So if you have less caster, I think you will need less toe out, for a given camber.

Cheers,

Bread

Now I'm in the forest, I was expecting 9mm, not 90mm. I thought the rake was 1-3 degrees in f1, maybe I just remember wrong.
I think the ok rake should be between 5 - 15 mm in gt6, like real cars. Am I on the map again?
Jouni

Wheel base makes one line, the rake variation on the rear makes the right angle, then what we have left is the line from the front wheel to the rake height of the rear giving us our angle

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Line B is the wheel base, and A is the difference of rake. Once the car is level this "zeros" the number, then any additional mm become the length of line A. The angle of rake is the angle of B and C..

Some might say equal numbers on ride height setting is level but I disagree. Level to me is when the underbody sits level with the track regardless if the numbers on the settings page are different. I call rake any additional angle from a level sitting car. I find adding a lil rake will account for weight transfer on acceleration , reduces squat basically and a lil rake can keep her level banging gears, 1st n 2nd I don't care so much as the rest, as the cars building speed. On race cars the downforce can make the rear squat rake counters this effect so slow the rake is visible but as speed builds up the car sits level.

A level car is IMO most predictable and tuneable, this is where we make sure our suspension has room to travel if we need to execute maneuvers. If a cars too low on soft springs downforce can have the car sitting on the bump stops no room for the suspension to work.

[S]I'm maybe stupid or ground oriented, I'm counting rake like this:
Wheel base x 2 is 45°, 1° rake is wheel base / 45, and answer is difference how much rear had to be higher.. Is this shooting far?

Yes I'm shooting far, counted and ground oriented way is out and far

Good triangle calculator sinister!

Still laughing my ground oriented thinking, understanding why it's not working. Lol
Where is delete button

After thinking, 2πr/360=1°, why didn't think before started write.. Lol. Wheel base is same as circle radius. But still out.. Maybe I should sleep for while, and..[/S] Delete this message tomorrow, no evidence of my brainfarts ..

I thought it might be interesting to talk about the characteristics of different types of grip. We have mechanical grip, this is what we are tuning our suspensions for. We then have Aero grip and tires grip.

All 3 play on our grip but each does so differently. The total grip we have is a combination of all 3.

The 3 are different but playing on the same thing.

Absolutely, interesting idea.
Jouni

Here's a few logs for the aerodynamics fire....

1) do front aero attachments do anything (front downforce is zero on tuning menu)? I've not seen any changes in top speed on route X.

2) with a rear wing (or front aero). What is the effect of rake? Does it affect wing angle and therefore downforce? What about under/oversteer balance? (with N24 gtr a few versions ago, the lower end had more grip... But I think that car has flat floor which may be having an effect?)

Cheers,

Bread

1) front aero attachments do something, adding small amount of aero drag on front, if that should put on number would guess around 4 +/-1
I have my 8-6 just on good demo shape for front aero, current setup it is balanced with rear wing, but taking rear wing or front aero out and it's bad, but taking both it is still in fine balance.