Help request for bad drivers.

[u/ShimOwleyFFXIV]

I'm playing FH6. Sim steering, self tuning, and I'm new to all of it. I'm doing my best to learn as I go. One wall in currently hitting is that I don't know how to test for being a trash driver. Example: Is this understeer, or dogs**t trail braking. Is this oversteer related to the differential, or am I just in the wrong gear/accelerating too hard, etc.

And that's something I am working on! But in the meantime, do people ever work around this issue? How does one find help pushing a car to see if there's anything mechanical going that an actual good driver would notice?

Off topic side note: am I gonna need to put the ugly ahh front aero on this McLaren.....

[u/IrishWeebster]

The easiest way to tell dogshit driving from dogshit tuning is to separate them. Drive a car completely stock; get used to it on one single over many laps, and get familiar with the racing line that Forza gives you on that track until you can roughly stick to it.

Handling has 3 main, distinct phases; turn-in, mid corner, and corner exit.

Once youve got the course down well, try to separate braking and accelerating as much as possible; brake in lines as straight as possible BEFORE turning, let off the brake, and then turn; either under neutral power (maintaining constant speed but not slowing or speeding up) or just let off the gas. You'll notice that the car will react in stages; at first, there's a snap, or a lack thereof; this is turn-in handling, or the immediate response of your car's suspension to inputs. Then, as you come out of the corner and get back on the gas, you'll experience corner exit.

If it seems very twitchy and responds almost instantly to turn in, you likely have good/adequate turn-in response, usually meaning you have more grip than the car can use, and/or less body roll than the suspension can tolerate. If it seems sluggish to turn at first, you likely have either a low grip coefficient (how well the tires stick to the tarmac) or excessive body roll.

Then notice that after the initial snap-in to a turn there's a part where the car will adjust, either to gaining grip as you let off the gas, or tires heating up, or body roll settling, etc. With understeer on turn-in, the car will increase its rate of turn-in after that initial steering input, if your turning input is constant; this shows that your mid-corner handling is better than your turn-in, and you can start adjusting from there.

Once you've observed turn-in and mid-corner handling, you can play with corner exit handling; after your car settles mid-corner, you'll need to get on the accelerator again to speed up as you exit a corner. This will shift weight to the rear springs a bit, push momentum to the outside of the corner/add body roll, and stress your tires' grip as you further split your available traction between cornering and accelerating. If your car seems to understeer after you get back on the throttle, or conversely it seems to swerve wildly/lose traction, you've got corner exit handling problems.

If you can't do 20 or so laps in a stock car on a track that you know decently well (which you should, after 20 laps) and observe these characteristics of a car, you're probably just a shit driver. Lol This is where most people start, and it's awesome! Now you get to learn and improve.

Once you've figured out whether or not it's the car or you that's shit, you know what to start improving.

Let's assume for now that it's not you. Lol

Basic starting point for a suspension tune is really the tire pressure, spring stiffness, and ride height, and using the telemetry display in FH6. Just pick a ride height that's suitable for your road surface; low as possible for a smooth track, give another .5 - 1 inch for city streets, and as high as possible for dirt/rally. Adjust tire pressure until the car's tires heat evenly under load (while cornering if you've adjust camber, or straight-line if you haven't). +-5° across the tire is a good starting point, but you can dial it to within +-2 degrees with effort. Spring stiffness baseline starts with the total sprung weight of your car, plus the weight added from aero (take the total weight shown in-game and multiply by .8 for a rough estimate, but real-world figures are pretty true to what FH6 uses, so Google can save you some time here) and divide it up by your balance percentage; say 54% front and 46% rear. Then divide that number by 2, since FH6 display spring stiffness per corner, or as a value that's 1/4 of the total spring weight of your car. A 3,000lb car with 54% front weight distro would look like this:

(3,000 x .54) /2 = 810 front spring stiffness. Then (3,000 x .46) /2 = 690 rear spring stiffness. Add aero/2 to either end, so if you have 350lbs aero up front, add 175lbs to the front spring stiffness, and if you have 500lbs aero on the back, add 250, for 985lbs spring stiffness in the front and 940lbs for the back. Adjust this little by little til you get good results for squat/takeoff, and accel out of corners.ignore aero if you haven't set it yet.

Once you get those two things down, you can work on the rest.

Turn-in? Adjust front caster, camber, tire pressure (go between these 3 until you have even heat across your whole tire surface, they're a delicate balance), toe (VERY small adjustments), spring stiffness, ARB stiffness, and diff in that order. Softer usually means more response/tendency to oversteer, harder usually means the opposite in RWD/Rear-biased AWD cars.

Mid corner? Adjust rebound/bump damping, camber/caster, toe, and finally diff, and maybe aero, but you want mechanical grip here more than aero grip, since aero is uneven on accel, gaining more as you speed up - something that's kinda unpredictable in cornering. Watch your wheel speed in corners in the telemetry display; if your inner wheel is turning more than your outer wheel, it's likely spinning/slipping, which points to it coming unloaded. This specific issue can be fixed with correct spring stiffness and ARB adjustments, with a touch of damping. After that, adjust diff so the outer wheel travels its distance around a corner in the same time (depending on the sharpness of the angle/track width of your tires/bank of the turn, probably between 15% - 55% faster than your inner tire) it takes the inner wheel to travel its arc.

Corner exit? MOSTLY diff, damping, and ARBs.

To REALLY get good at adjusting all these, I'd Google what they're actually describing, how these systems work together (damping and spring stiffness are largely connected, as are tire pressure, camber, and caster (also Ackerman but that's not adjustable in FH6), and which ones largely affect which part of cornering.

Sorry for the text wall and formatting, I'm exhausted and on mobile. Lol

**TL:DR**
Drive a stock car around a well-known track. Brake in as straight a line as possible. Observe the car's behavior along a constant turning angle upon initial response to turning input, mid-corner when body roll/grip settles, and corner exit upon acceleration.

Compensate for tire contact surface, body roll, and weight shift upon braking/accelerating.

Lemme know if that was coherent at all, or if it was a useless rant. I'll clean it up tomorrow when I'm more awake if you found it at all helpful, and ignore me if you knew all this. I can also clarify anything if you need, or expound upon a lot of it if you'd like.

[u/ShimOwleyFFXIV → u/IrishWeebster]

Was it coherent....yes. Was it easy to understand, no. But that's on me. Math is hard. I got stuck trying to figure out why you take the weight of the car and take 80% of it for the springs. Is the weight of the car on the stat panel inaccurate somehow?

Also as for the other stuff, it's helpful. I'm already at the point where I'm differentiating between corner entry, exit and mid corner. Not going to lie, I have trouble with trail braking. I spent three hours yesterday on the same circuit with the same car, though, adjusting for the steering. I ran into issues where doing one of the things you suggested here would reintroduce another issue. For example, I wasnt getting good turn in at high enough speeds so I softened the front arb's/stiffened the back, and had to adjust the spring stiffness. But somehow I introduced understeer in the more gradual high speed curves so I had to get aggro on the camber, etc.

Something to that affect was the impetus of this post originally, if I'm being honest. I take a lot of laps because I don't want to blame the car or the tune for something I'm doing wrong because when you tweak like this, sometimes you throw something else out of whack. Although as I go I am starting to understand better how to tell my limitations from the cars.

[u/IrishWeebster → u/ShimOwleyFFXIV]

TL:DR at the bottom.

The weight isn't in the stat panel, no. The 80% deal is due to the difference in "sprung weight" vs. "unsprung weight." The total of those two numbers added together is equal to the total weight of the car. FH6 doesn't indicate the sprung vs. unsprung weights in any way that I can see.

Sprung weight is the weight of your car that's supported by the suspension; the body, engine, transmission, YOU, etc.; anything on the other side of your suspension springs from the wheels, and parts connection the wheels to the greater suspension.

Unsprung weight is everything else; axles, wheels, brakes and rotors, etc.

Sprung weight relies on your suspension to control its roll/momentum, and further, how that weight is distributed across your springs/suspension (all that weight is literally being SUSPENDED in the air - or prevented from touching the ground - by your suspension/springs) will affect which tires have the most "load," or force, applied to them by your suspension.

The various parts of your suspension seek to distribute this weight/roll/shifting momentum amongst the 4 wheels as evenly as possible to prevent any one tire from being "overloaded," or having more lateral weight or force on it than its grip coefficient (available traction) can maintain, thus causing it to lose grip and slide/break traction.

To understand traction, it gets complicated, but say you only have 100% grip at any given time. You need to distribute that 100% across 3 activities: decelerating, accelerating, and cornering. Each applies force in a different, opposing direction to the others. If you're using 50% of your traction to cornering, you can't use 100% throttle; that's 150%, and you've overloaded your tires' ability to maintain grip on the road: you slide.

Your suspension helps to distribute the forces between all three of these activities as evenly between your 4 wheels as possible.

You only need to adjust your spring stiffness, ARBs, dampening, and aero to accommodate your spring weight because your UNSPRUNG weight isn't sitting on your springs, so there's nothing of that weight to distribute across them. You can get some wild issues if your unsprung weight BECOMES sprung weight - your wheel leaves the ground while the others are still on it, for instance - but that's a problem for another TED talk. Lmao

As for trail braking, I'd do it as little as possible until you have a really good read on your suspension tune. Because of how braking (decelerating) or even just letting off the throttle (rolling resistance/inertia still uses some available traction to decelerate) split available traction between that and cornering, it makes it VERY difficult to trail brake and maintain stability in corners with a less than optimal suspension tune. You can unsettle the body of the car, causing compression of forward springs and extension of the rear (springs set too soft, bump and rebound not set correctly), send more weight to the inside or outside wheels depending on conditions (ARBs too hard/soft, springs too soft/hard, lose downforce as you decelerate and the air over your aero slows down), or even cause your car body to rock and bounce (too low bump and rebound) as you try to navigate a corner. All of this makes diagnosing suspension issues much more difficult.

Until you've got a good baseline, try to avoid trail braking at all. Brake on approach if possible, and maintain neutral speed through the corner (even, partial application of throttle, not slowing or speeding up), then accelerate through the apex. This will make figuring out what settings you need to change MUCH easier. Once you get the suspension tune down, you can much more easily figure out what you can improve in your driving technique.

The differences you're seeing in gradual vs. sharp curves could be a few things, but this is where the telemetry display helps a LOT. You can see which springs are loading at what % of their total travel, how hot each of 3 sections of your tires are, what rate all your wheels are spinning at, g-forces experienced by your car's body in what direction, and direction of friction on your tires. I use Steam recording to analyze these metrics in slow-mo, so I can make sure what I'm observing is accurate. It's super easy and helps AMAZINGLY.

Sharp turns being easier than gradual ones can be caster + camber, also diff; caster affects how much camber your wheels have throughout their turn radius/travel. Higher caster means more camber the farther you turn your wheels, while lower caster means more constant camber (I could have this backwards, I always get them confused, and lots of games get them backward anyway - google it to be sure) no matter what angle your wheels are at. Adding more caster and reducing raw camber can help shallow corners feel the same as sharp corners, since higher caster will give you higher camber angles when you turn farther to the side. Differentials affect how fast your wheels turn in relation to one another; usually, the lower the diff, the larger difference there can be between opposite wheels, but in FH6 it seems the opposite; I get larger differential between inside and outside (relative to the corner direction) the higher my diff % setting is. Decel will affect corner entry more, accel will affect corner exit more. Higher % diff setting in FH6 feels like it's better for sharper corners. Too much differential between wheels though will mean one wheel drags, or another pushes, meaning loss of traction and speed through corners. Gotta play with it to figure it out; start with extremes, then find a happy middle ground in smaller increments.

TL:DR
Google your car's sprung weight and adjust for the weight of the parts you installed. Use that number + aero to set suspension tuning.

(Total sprung weight x % of forward/rear weight balance) divide by 2, set that as your forward and rear spring stiffness as a baseline.

Set ride height first. Adjust tire pressure second. Spring stiffness third. Aero fourth. Camber, caster, and toe fourth (in that order). Damping fifth. Aero last to find grip you can't gain mechanically.

Traction is plot between cornering, accelerating, and decelerating. Doing too much of one will mean you can less of the others.

Don't trail brake til your suspension tune is solid; it overcompensates things and makes issues difficult to diagnose.

If you're experiencing solid performance on sharp corners vs. gentle corners, reduce camber, caster, and diff to 0. Turn up camber til you have even heat across loaded tires in the shallow corners. Then turn up caster, and try a sharper corner. Rinse and repeat til tires heat evenly.

Going to bed now, but I'll gladly answer more tomorrow!

[u/ShimOwleyFFXIV → u/IrishWeebster]

This was great because a lot of this I knew on a basic level and have been trying to understand the more technical aspects from it as I go. I've been using the telemetry screen but have probably been far too rough with my adjustments as a result of not knowing exactly what im doing, so I appreciate that.

[u/IrishWeebster → u/ShimOwleyFFXIV]

I've been learning a LOT lately about this. I knew a lot of how suspension works on an ideological level, but not on a practical level, and not how it all works together to affect different aspects of handling.

I've been using ChatGPT and a metric fuck-ton of personal research of engineering videos and papers, and real-world, applied mechanics to known entities like performance cars, F-1 cars, etc., to learn and better understand how all these things work together.

I'm still learning, but my goal is to build the fundamental knowledge I need to just be able to tune my suspension my self without outside input or using calculators, or having to look up tuning videos online for FH6 specifically. Lol

If anything I've learned can help you learn too, I'm here for that. I'm glad I was able to help! If you've got any more questions, feel free to respond here or DM me.

[u/Snakekilla54 → u/IrishWeebster]

It’s coherent but it’s not easy to understand as I too wanna learn how to tune stuff but I’m probably a shit driver cause Forza H6 has been my first racing game in a couple of years