Since the forums are going to be shuttered soon, as goodbye and thank you for all the years of info I acquired as a lurker, I figured that it wont do too much harm to the competitive scene to post this thread. (It will also reduce the number of Beats out there.) What also prompts me to make this thread is Sepi’s (RIP his account, dont mod) recent video “The Tuning Disaster of Racing Games” which pointed out some idiosyncrasies about FH6 that differ from real-world or other racing sims.
I’ve seen some silly ideas lately, particularly on Reddit, some folks using AI… for a game that hasnt been out long enough to even be trained on yet! 
1: Stats
Tuning in Forza has always been about getting the best Grip and Power-to-Weight Ratio within the Performance Index / Class (D, C, A, etc.) Since PI is based on Performance Stats (1-10 in Handling, Speed, etc) not things like Horsepower to Weight and G Tolerance, it is very simple to build fast cars by avoiding over-shooting Performance Stats.
The stats we should focus on in FH6 are:
HP-to-Weight (PWR)
Lateral Gs
The Stats we need to Tune for are:
Aero Balance
Top Speed & Acceleration
Mechanical Balance
2: Physics
The Physics in all Forza games works counter to most racing games and real life. Simply put. all cars should be at maximum ride height with the front slightly higher than the back. This is due to a quark, from what I can tell that tricks the game-engine into thinking the car is going downhill while accelerating. Aside from this, maximizing the amount of body roll onto a single wheel avoids breaking traction in Forza games because, again, due to the way the physics engine is set up, traction is shared between both wheels. This is also why the Peel/Reliant are so powerful of Drag vehicles, one wheel does the work of two resulting in more traction instead of less.
AWD should be your preferred. Yes, other drivelines get you bigger stats, but they get you crappy physics due to wheel slip.
3: Tires
Tires get their own category since there seem to be so many myths surrounding how they work. Simply, different tire surfaces increase Lateral G tolerance at the expense of greater PI. Lighter cars do not need their Lateral G tolerance increased, which is what makes Drag Tires a viable option on light cars. Likewise, Rally/Snow/Offroad tires have an invisible value that inverts their grip ratings (G tolerance) in their stated conditions at the expense of certain PI costs depending on the car.
In FM7/FH6 Wheels/Tires got additional buffs in the form of wheel width, use this stat as much as you can unless you find it effects the physics of the car too much. If your car “Forklift” drives no matter how much you tune take some width out of the back. (In real life, yes, we would add width but that doesnt matter, this is Forza)
4: Parts
Rally/Offroad Transmission parts are faster even after tuning to the same ratings. I dont know why. Dont use anything else. Ever. Stick to a 6/7 Speed or 4 Speed transmission. Elsewhere, You do NOT need to always stick the best parts possible on. Again, our goal is to change our “Mechanical Balance” and our Power-to-Weight within a PI… not be “as light as possible!!! 11!! one”
Aero should almost always be considered at first: you need the additional traction, PI loss, or balance.
~I CANNOT STRESS THIS ENOUGH BUILD AWD!~*** You can always move the differential 100% back or forward, but you cannot change wheel slip on your freewheels on FWD/RWD! This has a HUGE effect on your handling!
5: Tuning
The hard part. (Sort of)
All cars should be Soft in front, Stiff in back. Your goal while tuning is going to incrementally increase your mechanical advantage to increase body roll and traction when turning. This is again, is done simply by, as previously mentioned, putting as much weight as possible onto one wheel by using a combination of the Anti-Rollbars and Springs. Use this to find a good Mechanical Balance that allows the car to roll onto the front wheel that matches the turn you are taking on.
Use Damping to counter understeer/oversteer or “snapping” out of turns.
Your Aerodynamics should be used to get more traction, where you need it.
Differential settings are used to counter wheel slip. Pay attention to when your car breaks traction when trying to accelerate in a turn. Its usually your deccel stats. 75-90A over 6-12D across both axles is good for most situations as a baseline.
Alignment is where most of your tuning is going to happen. Default Camber is usually good. A little toe out (less than a degree) goes a LONG way if you have done the above right.
Tire Pressure:
There is rarely any situation in FH6 your TP should be above 16PSI/1.1BAR.
Gear Ratio:
Best of luck, people go to college for this. Start with final drive and make your baseline fast and then work on your 50-100/Top Speed. Keep in mind that power is split between how fast you can accelerate and how fast you can go, accelerating faster is better for most races.
I hope this “guide” helps, or at least gets you to stop using the absolutely cheeks shared Tunes.
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