Forza 7 Tuning Guide

Part 2 - General Tuning

This part explains how to setup cars in a way that they will work good on all tracks.

 

This also serves a basis for grip and speed tuning as well as track specific tuning which will be covered in part 3 and 4, so make sure to read this first before advancing to track specific tuning.

Understanding Tuning Relevant Car Properties

As in Part 1 explained car type, body type and drive type are the most important factors when it comes to tuning, but there are also other individual car properties that have great impact on the tuning, most notable are power and weight.

The following table gives an overview which car property affects which tuning area. Please refer to the related section in the tuning guide for detailed explanations.

Car Property           Tires        Gearing       Alignment         ARBs         Springs         Dampers       Aero        Brakes       Diff

                                                                                           

Car Type                      ✓                                                                                                                                                        ✓                 

Body Type                                                                 ✓                     ✓                  ✓                     ✓                                                      ✓

Car Design                  ✓                                           ✓                                                                  ✓                                      ✓             ✓

Drive Type                   ✓                                           ✓                     ✓                  ✓                     ✓                  ✓                 ✓             ✓

Power                                                ✓                                             ✓1                ✓1                                         ✓1

Weight                                                                                               ✓                  ✓                     ✓                  ✓                    

Chassis Reinf.                                                                                   ✓                  ✓                            

Tire Compound          ✓         

Tire Width                                                                   ✓                                        ✓

Aero Kits                                                                                                                ✓                    ✓                   ✓

only in special cases

Tires

Tire pressure tuning first and foremost depends on the used tire compound. The general rule here is the softer the tire compound the higher tire pressure is required. Reasoning for that is that besides grip tires also provide a basic level of rigidity and therefore control. Softer tire compounds like Sport or Race compound provide more grip but also have less rigidity than Stock or Street compound. Increased tire pressure compensates for lower level of rigidity of softer compounds.

Generally for FR (front engine RWD) cars front and rear tire pressures should be the same. Having different tire pressures on front and rear tires creates over- or understeer effects and is only required when tuning for speed, grip or specific tracks.

Tire Compound      Front Tire Pressure      Rear  Tire Pressure

                                                (FR)                                  (FR)

Stock                                      28.0                                  28.0

Street                                     28.0                                  28.0

Sport                                      28.5                                  28.5

Race                                       29.0                                  29.0

Drag                                       29.5                                  29.5

If you are running on stock tire compound keep in my mind that the stock tire compound may not be Stock compound for all cars. For most race cars the stock tire compound is Race compound (only Drag compound is available as upgrade), likewise for some sports cars the stock tire compound is Sport compound (only Race and Drag compound available as upgrade). Set the tire pressures accordingly.

Note: This method will provide peak tire performance starting 4th lap, the first three laps are needed to warm-up the tires.

Open Wheel Cars

Open wheel cars require lower tire pressure on the front and higher tire pressure on the rear as compared to regular closed wheel cars to stabilize the car while turning. 

                                                       Front Tire Pressure Offset      Rear  Tire Pressure Offset

Open Wheel Off-road Truck                           -0.5                                           +0.5

Open Wheel Off-road Car                               -1.0                                           +1.0

Open Wheel Street Car                                   -2.0                                           +2.0

Open Wheel Sports Car                                  -2.0                                           +2.0

Open Wheel Race Car                                     -4.0                                           +4.0

AWD and FWD Cars

AWD and FWD cars require lower tire pressure on the front and higher tire pressure on the rear as compared to RWD cars to stabilize the car while turning. 

                            Front Tire Pressure Offset      Rear  Tire Pressure Offset

AWD                                        -1.0                                           +1.0

FWD                                        -2.0                                           +2.0

Mid and Rear Engine Cars

Mid and rear engine cars require higher tire pressures on the front and lower tire pressures on the rear as compared to regular front engine cars.

                            Front Tire Pressure Offset      Rear  Tire Pressure Offset

Mid Engine                             +1.0                                             -1.0

Rear Engine                            +2.0                                             -2.0

Race Cars and High Performance Cars

Aside from tire compound, drivetrain and engine position tire pressure tuning also depends on the type of car as high performance cars and race cars require higher tire pressure for improved control than street or sports cars. That means for high performance cars and race cars you need to add an additional 0.5 psi on top of the base tire pressure for best tire performance.

Car Type                            Tire Pressure Offset

High Performance Car                 +0.5

Race Car                                         +0.5

Race Truck                                     +0.5

Prototype Race Car                      +0.5

GP Race Car                                   +0.5

------------------------------------------------------------

Off-road Race Truck                     +0.5 

Alignment

Camber

Camber settings are car type specific. As a general rule of thumb: older cars require less static camber because the more flexible chassis / suspension creates more dynamic camber. Modern cars with more rigid chassis / suspension can be run with higher camber. However due to very high forces during cornering for GP race and prototype race cars its the other way around: older gp and prototype race cars require higher camber than modern GP and prototype race cars.

Static camber should be set so that the (dynamic) camber on the apex when you start accelerating out of a turn is around 0 to maximize tire contact patch which in turn provides maximum tire grip. This is especially important for the driven wheels. 

Front camber is usually higher than rear. Exception are open-wheel cars with its very unique suspension geometry that requires higher rear camber.

Car Type                               Usual Camber Range

                                                             (FR)

Utility  Car                                    -2.5 to  0.0

Street Car                                     -3.0 to  0.0

Sports Car                                    -3.0 to  0.0

High Performance Car               -2.5 to -1.0

Race Car                                       -2.5 to -1.5

Race Truck                                    -2.0 to 0.0

Prototype Race Car                     -2.5 to -0.5

GP Race Car                                 -3.0 to -0.5

------------------------------------------------------------

Off-road Car                                -3.0 to  0.0

Off-road Sports Car                   -3.0 to  0.0

Off-road Truck                            -2.0 to  0.0

Off-road Race Truck                   -2.0 to  0.0

The ranges given account for different body types within the car type.

Open Wheel Cars

Open wheel cars require lower rear camber than regular closed wheel cars to compensate for less body roll on the rear.

                                                                       Rear Camber Offset

Open Wheel Off-road Truck                                   +0.1

Open Wheel Off-road Car                                       +0.2

Open Wheel Street Car                                            +0.4

Open Wheel Sports Car                                           +0.4

Open Wheel Race Car                                              +0.8

AWD and FWD Cars

FWD cars require more front camber than RWD cars to compensate for more front body roll. AWD cars require more front and rear camber than RWD cars.

                           Front Camber Offset         Rear Camber Offset

AWD                                  -0.2                                     -0.2

FWD                                  -0.4                                       0.0

Mid and Rear Engine Cars

Mid engine cars require higher front and rear camber and rear engine cars require higher rear camber than regular front engine cars.

                           Front Camber Offset         Rear Camber Offset

Mid Engine                        -0.2                                     -0.2

Rear Engine                        0.0                                     -0.4

Relevant Car Upgrades

Rel

Tire width directly influence camber settings. This is due to wider tires increase contact patch, so for optimal grip camber needs to be reduced to compensate for added contact patch size.

Car Property              Change             Effect on Camber

Front Tire Width         Increase           Reduce front camber

Front Tire Width         Decrease         Increase front camber

Rear Tire Width          Increase            Reduce rear camber

Rear Tire Width          Decrease          Increase rear camber

Toe

For most cars there is no need adjust toe as this from my experience creates almost always unwanted imbalance during turning.

Exceptions are older road and off-road cars that require slight rear toe-in (max. -0.3) to combat on-throttle understeer.

Car Type                                  Front Toe         Rear Toe

Utility Car                                        0.0                -0.3-0.0

Street Car                                        0.0                -0.3-0.0

Sports Car                                       0.0                -0.3-0.0

High Performance Car                  0.0                    0.0

Race Car                                          0.0                    0.0

Race Truck                                      0.0                    0.0

Prototype Race Car                       0.0                    0.0 

GP Race Car                                    0.0                    0.0 

-----------------------------------------------------------------------------

Off-road Car                                  0.0                -0.3-0.0

Off-road Sports Car                     0.0                -0.3-0.0

Off-road Truck                               0.0               -0.3-0.0

Off-road Race Truck                     0.0                     0.0  

The ranges given account for different body types within the car type.

Caster

Caster is also a car type specific setting. As a general rule of thumb older cars require higher caster than modern cars, race cars require lower caster than production cars and off-road cars require lower caster than road cars.

 

Due to high forces during cornering GP race cars and prototype races cars generally need high caster that provides extra stability during cornering.

Each car has a "natural" caster that suits the cars suspension geometry best. You wont unlock the full potential of a car when the caster is not set to the cars natural caster.

Car Type                                               Caster

Utility Car                                          5.0/6.0/7.0 

Street Car                                          5.0/6.0/7.0

Sports Car                                         5.0/6.0/7.0

High Performance Car                          5.0 

Race Car                                              4.0/5.0

Race Truck                                              4.0

Prototype Race Car                               6.0

GP Race Car                                            7.0

-----------------------------------------------------------------

Off-road Car                                           4.0

Off-road Sports Car                              4.0

Off-road Truck                                       4.0

Off-road Race Truck                          1.0/2.0 

The different values given account for different body types within the car type.

Open Wheel Cars

Open wheel road cars require higher caster than regular closed wheel cars to stabilize the car while turning. Open wheel off-road cars require lower caster than regular off-road cars for improved corner entry.

                                                                 Caster

Open Wheel Street Car                             6.0

Open Wheel Sports Car                        6.0/7.0

Open Wheel Race Car                              7.0

----------------------------------------------------------------

Open Wheel Off-road Car                    2.0/3.0

Open Wheel Off-road Sports Car           2.0

Open Wheel Off-road Truck                1.0/2.0

The different values given account for different body types within the car type.

Anti-roll Bars

Anti-roll bars (ARBs) control the weight transition between left and right (or inner and outer) wheels during cornering. Softer ARBs create more body roll leading to more weight shifting to the outer wheels. Stiffer ARBs reduce body roll and thus provide less weight shifting during cornering. Soft ARBs provide more grip during cornering but can result into sluggish car behaviour when setup too soft. Stiff ARBs provide more control during cornering but can result into harsh and unpredictable car behaviour when setup too stiff. 

Generally ARBs need to be setup in relation to chassis stiffness and vehicle weight, i.e. the more rigid the chassis is the lower the ARBs can be set. Likewise the less the car weights the lower the ARBs can be set.

20/20 is good middle ground for modern road cars around 3000lbs and 50% weight distribution and corresponds to an ARB stiffness of around 63%. Increase ARBs for cars with more weight and / or less rigid chassis (e.g. older cars). Decrease ARBs for cars with less weight and / or more rigid chassis (e.g. race cars).

Front and rear ARB distribution has a relation to weight distribution, so in general a car with more front weight should have also higher front ARBs than rear. This is however not as simple as 1:1 distribution according to weight distribution because springs and dampers also affect car balance during turning. 

A good starting point for ARB distribution for RWD cars is 1 per 1% weight distribution difference to 50%, i.e. for 51% front weight distribution the front ARB should be 1 higher than the rear ARB. Older cars and muscle cars require higher spread (>1 per 1%) while race cars require lower spread. 

Example: ARBs for a modern RWD road car with 3000lbs @ 51% wd would be:

ARB distribution = 51%-50% = 1% --> 1*1 = 1, divide by 2 to split equally between front and rear --> 0.5

Front: 20 + 0.5 = 20.5 and Rear: 20 - 0.5 = 19.5.

Car Type                         ARB stiffness         ARB distribution

                                                                                       (FR)

Utility Car                             63-66%                      1.00-2.95

Street Car                             63-66%                      0.98-1.50

Sports Car                            61-65%                      0.66-1.00

High Performance Car       40-55%                      0.55-0.65

Race Car                               35-62%                      0.35-0.80

Race Truck                              15%                              0.15

Prototype Race Car             80-89%                      0.25-0.35

GP Race Car                          84-90%                      0.15-0.35

---------------------------------------------------------------------------------------

Off-road Car                         63-65%                      1.00-2.95

Off-road Sports Car             63-65%                      1.00-2.95

Off-road Truck                      61-65%                      1.50-3.00

Off-road Race Truck                63%                        1.50-1.95

-

The ranges given account for different body types within the car type.

ARB Stiffness

ARB stiffness is a metric to calculate ARB base values based on the cars weight and a weight distribution of 50%.

The formula to determine ARBs for a given ARB stiffness and a weight distribution of 50% looks like this:

Base ARB = (Weight / 2) / (200 - 200 * ARB stiffness)

Example: Street Car with 2500 lb and ARB stiffness of 63% and ARB distribution of 1.00:

Base ARB = (2500 / 2) / (200 - 200 * 63%) = 16.89 

 

Depending on the cars weight distribution and ARB distribution front and rear ARBs are distributed around the ARB base value:

Weight Distribution              Front ARB           Rear ARB

          52%                                     17.89                  15.89

          51%                                     17.39                  16.39

          50%                                     16.89                  16.89

          49%                                     16.39                  17.39

          48%                                     15.89                  17.89

FWD Cars

For FWD cars generally ARBs need to be setup in reverse to RWD with regard to ARB distribution. So a good starting point would be -1 per 1% weight distribution for modern road cars around 3000lbs. 

Example: ARBs for a modern FWD street car with 3000lbs @ 60% wd would be:

ARB distribution = 60%-50% = 10% --> 10*-1 = -10, divide by 2 to split equally between front and rear --> -5

Front: 20 + (-5) = 15 and Rear: 20 - (-5) = 25

AWD Cars

AWD cars require a lower ARB distribution than RWD cars to combat inherent understeer. A good starting point is 0.66 -per 1% weight distribution for AWD cars, i.e. for 51% front weight distribution the front ARB should be 0.66 higher than rear ARB.  

Mid and Rear Engine Cars

Mid and rear engine cars require reverse setup of front and rear ARBs as compared to regular front engine cars.

High Power Cars

Cars with very high power (>=800hp for road cars or >=1.5*stock power for race cars) require additional ARB stiffness to stabilize the car. In this case simply doubling of the ARB values is required.

Relevant Car Upgrades

Adding chassis reinforcement upgrade increases chassis rigidity (sport chassis increases chassis rigidity by 3%, race chassis increases chassis rigidity by 6%), i.e. ARBs should be reduced accordingly.

Car Property                       Change                  Effect on ARBs

Weight                                   Increase                       Increase

Weight                                   Decrease                     Decrease

Power                                     Increase                      Increase1 

Chassis Reinforcem.              Street                             None

Chassis Reinforcem.               Sport                        Decrease2

Chassis Reinforcem.               Race                         Decrease3 

Only in special cases, see below

Reduce ARB stiffness by 3%

3 Reduce ARB stiffness by 6%

Springs

Springs control the weight transition during directional changes and between front and rear wheels during acceleration and braking. Softer springs provide more grip but can lead to sluggish car behaviour during directional changes or locking front wheels under braking and when setup too soft. Stiffer springs provide more control but can lead to harsh unpredictable car behaviour during directional changes or wheel spin when accelerating when setup too stiff.

Spring rates need to be setup in relation to car weight, weight distribution and chassis / suspension stiffness. More weight requires stiffer springs and more flexible chassis / suspension require higher spring rates on the non driven wheels (front for RWD) and lower spring rates on driven wheels (rear for RWD).

Distribution of front and rear spring rates is related to weight distribution, so cars with more front weight will require also higher front spring rates. As with ARBs this is not a simple 1:1 distribution according to weight distribution as for instance the drive wheels are usually run with lower springs rates in relation to non driven wheels to reduce wheel spin. 

As others suggested a good range is between 1/3 and 1/2 of the slider though there are exceptions where you need to run above or below that range.

These are the ranges for spring rates I usually operate (given in percentage of distributed front / rear weight) on RWD cars:

Car Type                          Front Spring Rate           Rear Spring Rate

                                                     (FR)                                     (FR)

Utility Car                                 93-100%                             57-80%

Street Car                                 93-100%                             57-80%

Sports Car                                 87-98%                               58-80%

High Performance Car            85-93%                               63-84%

Race Car                                    83-93%                               59-85%

Race Truck                                  80%                                     90%

Prototype Race Car                  82-93%                               49-89%
GP Race Race Car                    80-104%                              10-90%

-------------------------------------------------------------------------------------------------

Off-road Car                            94-100%                              57-80%

Off-road Sports Car                94-100%                              57-80%

Off-road Truck                         94-100%                              57-80%

Off-road Race Truck                   94%                                  57-80%

 

The ranges given account for different body types within the car type.

Example: RWD road car with 3000lbs @ 52% wd 

front springs would be between: 

3000 / 2 * 52% * 86% = 670 and 

3000 / 2 * 52% * 100% = 780  depending on body type.

AWD and FWD Cars

For AWD cars use the same spring rates as RWD cars. for FWD cars simply swap front and rear spring rates.

Mid and Rear Engine Cars

Mid and rear engine cars require reverse setup of front and rear springs as compared to regular front engine cars.

High Power Cars

Cars with very high power (>=800hp for road cars or >=1.5*stock power for race cars) require additional spring stiffness to stabilize the car. In this case simply doubling of the springs is required.

Relevant Car Upgrades

Adding chassis reinforcement upgrade increases chassis rigidity, i.e. springs should be reduced accordingly.

Increasing tire width also requires springs to be increased to compensate for added grip. For each 10 inch increase in tire width increase springs by 0.5%. This is usually in the range of 0-5lb depending on increased tire width.

Also when adding aero springs need to be increased to compensate for added downforce. However the exact impact of downforce on springs is not simple to determine as it not only involves the amount of added downforce but must also take into account the deviation of downforce from balanced downforce level.

Car Property                 Change                 Effect on Springs

Weight                             Increase                       Increase

Weight                            Decrease                      Decrease

Power                              Increase                        Increase1 

Front Tire Width            Increase              Increase front springs

Front Tire Width           Decrease             Decrease front springs

Rear Tire Width              Increase              Increase rear springs

Rear Tire Width             Decrease             Decrease rear springs

Front Downforce           Increase              Increase front springs

Front Downforce           Decrease            Decrease front springs

Rear Downforce             Increase              Increase rear springs

Rear Downforce             Decrease            Decrease rear springs

Chassis Reinforcem.        Street                            None

Chassis Reinforcem.        Sport                Decrease front springs2

Chassis Reinforcem.         Race                Decrease front springs3

Only in special cases, see below

Reduce front spring rate by 2.75%

Reduce front spring rate by 5.5%

Balanced Downforce

Balanced downforce levels depend on the cars weight distribution and are distributed around the cars aerodynamic ideal front weight distribution of 47%. For a car with 47% front weight distribution and a Standard Forza race aero kit (50-100/75-200) balanced downforce is achieved when downforce sliders are aligned, e.g. 50/75, 75/137 or 100/200. For cars with higher front weight distribution rear downforce slider must be higher than front downforce slider depending on how much the cars front weight distribution differs from 47%. Likewise for cars with lower front weight distribution rear downforce slider must be lower than front downforce slider to achieve balanced downforce levels. For each %1 difference of car weight distribution from 47% rear downforce must be increased or decreased by 1.866667lb.  So balanced downforce levels kind of equalize the deviation of the cars front weight distribution from the ideal 47% front weight distribution by increasing or decreasing rear downforce in relation to front downforce.

 

Usually balanced downforce only affects rear downforce but if balanced aero would require to increase rear downforce beyond maximum possible rear downforce, rear downforce is set to maximum and front aero is reduced instead. Likewise if balanced downforce would require to reduce rear downforce lower than minimum allowed front downforce, rear downforce is set to minimum and front downforce is increased instead.

Example: FWD road car with 64% wd, Standard Forza aerokit (50-100/75-200):

Balanced rear downforce for 75lb front downforce:

137 + (64-47) * 1.866667 = 168.7339 --> 169lb

To sum up the impact of downforce on springs consist of two factors:

  • amount of added downforce: for each 10lb added front downforce increase front springs by 0.5, for each 25lb added rear downforce increase rear springs by 0.5

  • deviation from balanced downforce: for each 2lb difference of front / rear downforce from balanced front / rear downforce increase or decrease front / rear springs by 0.5

Keep in mind that not only adjustable race aero kits provide downforce that has an impact on springs but also non-adjustable stock, street or sports aero kits, albeit much more subtle.

Aero Kit                            Downforce

Stock Front Bumper              10lb

Street Front Bumper             10lb

Sport Front Bumper              40lb

Stock Rear Wing1                   25lb

Street Rear Wing                    25lb

Sport Rear Wing                     70lb

Stock Rear Bumper                25lb

Street Rear Bumper               25lb

Sport Rear Bumper                50lb

Race Rear Bumper                 70lb                 

1 Many cars don't have a stock rear wing, so in this case there is no downforce applied

Example: FWD road car with 2198lb, 64% wd, stock aero (10/25/25), front springs: 563.9, rear springs 370.9

Adding front and rear race aero kit with stock downforce 75/137 (balanced downforce for 64% wd is 75/169)

Front spring offset: (75-10)/10=6.5, 6.5*0.5=3.25

Rear spring offset: (137-25)/25=4.48, 4.48*0.5=2.24,(137-169)/2=-16,-16*0.5=-8, total rear spring offset: 2.24-8=-5.76

New front springs: 563.9 + 3.25 = 567.15

New rear springs: 370.9 - 5.76 = 365.14

Ride Height

Ride height works as an additional stabilizing factor like aero and a higher ride height generally allows you to brake and accelerate faster. However raising ride height also raises the center of mass which hurts turning. So there is a sweet spot for setting up the ride height which I call optimal ride height.

The optimal ride height for a car is the lowest ride height possible that is not lower than the car types minimum ride height. Each car type has a minimum ride height that is required to have enough suspension travel during cornering. 

In general for older cars the minimum ride height is higher than for modern cars and for race cars the minimum ride height is lower than for productions cars.

Always keep front and rear ride height level , i.e. keep the sliders aligned. Having front and rear ride height sliders unaligned  creates over- or understeer effects and is only required when tuning for grip, speed or specific tracks.

Car Type                                 Min. Ride Height

Utility Car                                        4.0-6.0 

Street Car                                        4.0-6.0 

Sports Car                                       4.0-6.0 

High Performance Car                  3.0-4.0

Race Car                                          3.0-5.0

Race Truck                                          2.5

Prototype Race Car                        2.5-3.5 

GP Race Car                                    2.5-4.5

------------------------------------------------------------------

Off-road Car                                   4.0-5.0 

Off-road Sports Car                       4.0-5.0 

Off-road Truck                                4.0-5.0 

Off-road Race Truck                      4.0-5.0 

The ranges given account for different body types within the car type.

There are two exceptions:

 

1) Set ride height to lowest if the front ride height can be set below 2 inches

2) Set ride height to highest if the maximum front ride height is below the minimum ride height

Note: Minimum ride height works in 0.5 increments and is most of the time an integer number.

Mid and Rear Engine Cars

Mid and rear engine cars require reverse setup of front and rear ride height as compared to regular front engine cars. This may cause the sliders to be unaligned in case front and rear ride height have not the same value.

Dampers

Getting damping right is one of the hardest parts when it comes to tuning and from my experience separates good tunes from excellent tunes.

 

Dampers control weight transition during directional changes and while turning. Bump helps you in initiating a directional change or entering a turn while rebound helps to maintain the speed while turning.

 

Setting bump too soft can result into corner diving while braking and entering a turn. Also too soft bump can make the car unresponsive to directional changes and provoking oscillation of the front springs making the car very bouncy. Setting bump too stiff can result in understeer while entering a turn. It also can create rear tire spin while accelerating out of a corner.

 

Setting rebound too soft makes the car oversteer on corner entry and generally unresponsive to directional changes. Setting rebound to stiff creates understeer during corner entry and while turning.

Generally damping stiffness must be set in relation to chassis / suspension stiffness, i.e. a car with more rigid chassis / suspension requires higher overall damping stiffness. Damping stiffness is the sum of bump and rebound.

 

Bump has a direct relation to front car weight and suspension stiffness, i.e. the higher the cars front weight is the higher the bump is required to avoid diving on turn-in. Also cars with stiffer suspension require less bump whereas older cars with softer suspension require stiffer bump. 

Rebound has a direct relation to chassis stiffness, the more rigid the chassis is the higher the rebound must be set. 

Rebound should be most of the time higher than Bump. Exceptions can be very heavy cars with low damping stiffness like trucks that lead to very high bump and low rebound.

Car Type                                    Front Rebound           Front Bump

                                                             (FR)                                (FR)

Utility Car                                         6.0-8.0                           4.0-5.0

Street Car                                         6.0-8.0                           4.0-5.0

Sports Car                                        6.0-8.0                           4.0-5.0

High Performance Car                   8.0-9.0                           4.0-5.0

Race Car                                           7.5-9.0                           4.0-5.0

Race Truck                                        7.5-8.0                           6.0-6.5                           

Prototype Race Car                         8.5-9.5                          4.0-4.5

GP Race Car                                     8.0-9.5                          3.5-4.5

------------------------------------------------------------------------------------------------

Off-road Car                                    6.0-7.5                          3.0-5.0

Off-road Sports Car                       6.0-7.5                          3.0-5.0

Off-road Truck                                6.0-7.5                          4.5-5.5

Off-road Race Truck                       6.0-7.5                          4.5-5.5

The ranges given account for different body types within the car type and weight ranges.

The relation between front and rear dampers should mirror the relation of front and rear spring rates, i.e. if the front spring rate is lower than the rear spring percentage rate the front dampers should also be lower than the rear dampers and vice versa. 

That means rear rebound and rear bump are set to front rebound and front bump plus an offset according to front and rear spring rate difference.

Front-Rear Spring Rate      Rear Rebound Offset      Rear Bump Offset

Difference                                            (FR)                                   (FR)                  

<-10%                                                    +0.4                                   +0.2

<-5%                                                      +0.2                                   +0.1

-5%-1.5%                                               -0.2                                    -0.1

1.5-35%                                                 -0.3                                    -0.2

36-40%                                                  -0.6                                    -0.4

>40%                                                      -1.2                                    -0.8

Example: RWD car with front spring rate 80%, rear spring rate is 50%

Spring rate difference: 80%-50% = 30%

Rear rebound should be 0.3 lower than front rebound

Rear bump should be 0.2 lower than front bump

Prototype Race Cars and GP Race Cars

Prototype race cars and GP race cars require additional stiffening of rear dampers to stabilize the car due to higher forces on the chassis during cornering.

Car Type                                Rear Rebound Offset      Rear Bump Offset      

Prototype Race Car                             +3.5                                   +3.5   

GP Race Car                                          +3.5                                   +3.5   

Open Wheel Cars 

Open wheel cars cars require reverse setup of front and rear bump as compared to regular closed wheel cars and also a stiffer rear bump for improved cornering.

                                                                                              Rear Bump Offset        

Open Wheel Street Off-road Truck                                            +0.5   

Open Wheel Street Off-road Car                                                +1.5 

Open Wheel Street Car                                                                +2.5 

Open Wheel Sports Car                                                               +2.

Open Wheel Race Car1                                                                 +3.

1 except GP race cars

AWD and FWD Cars

 

AWD and FWD cars require higher front dampers to stabilize the car on corner entry.

                                Front Rebound Offset         Rear Rebound Offset     Front Bump Offset     Rear Bump Offset  

AWD                                      +1.5                                          0.0                                    +1.5                                0.0

FWD                                       +2.5                                          0.0                                    +2.5                                0.0

Mid and Rear Engine Cars

Mid engine cars require reverse setup of front and rear rebound as compared to regular front engine cars. They also require a stiffer rear rebound and front bump than regular front engine cars.

Rear engine cars require reverse setup of front and rear rebound and bump as compared to regular front engine cars. They also require a stiffer rear rebound and rear bump than regular front engine cars.

                                Front Rebound Offset         Rear Rebound Offset     Front Bump Offset     Rear Bump Offset  

Mid Engine                             0.0                                          +1.5                                    +1.5                                0.0

Rear Engine                            0.0                                          +2.5                                      0.0                               +2.5

Relevant Car Upgrades

When decreasing weight bump might need to be decreased and rebound need to be increased to compensate for reduced front weight, for every 100lb front weight reduction rebound needs to increased by 0.1 and bump needs to be reduced by 0.1. Similarily when adding front weight, rebound has to be reduced and bump has to be increased.

When adding aero bump might need to be increased and rebound need to be decreased to compensate for added front downforce, this is usually in the range of 0.1-0.3 depending on amount of added downforce.

Car Property                Change            Effect on Rebound / Bump

Front Weight                 Increase                Decrease / Increase

Front Weight                Decrease               Increase / Decrease 

Front Downforce          Increase                Decrease / Increase

Front Downforce         Decrease                Increase / Decrease 

Brakes

Brake tuning in Forza depends on the type of car and the type of drivetrain. Generally speaking race cars require more braking force on the rear and higher brake pressure than road cars and off-road cars require more braking force on the front and lower tire pressure than road cars.

Car Type                          Brake Distribution        Brake Pressure

                                                       (FR)                                  (FR)

Utility Car                                      50%                                120%    

Street Car                                      48%                                125%    

Sports Car                                     48%                                125%    

High Performance Car                44%                                145%

Race Car                                        44%                                145%

Race Truck                                    44%                                145%

Prototype Race Car                     44%                                145%

GP Race Car                                  52%                                125%

---------------------------------------------------------------------------------------------

Off-road Car                                 52%                                115%

Off-road Sports Car                    52%                                115%

Off-road Truck                             48%                                135%

Off-road Race Truck                    48%                                135%

Open Wheel Cars

Open wheel cars require more braking force on the front and a lower brake pressure than regular closed wheel cars to stabilize the car while braking.

                                                           Brake Distribution Offset      Brake Pressure Offset

Open Wheel Off-road Truck                              0%                                                0%    

Open Wheel Off-road Car                                 +2%                                             -5%    

Open Wheel Off-road Sport Car                       +2%                                             -5%    

Open Wheel Street Car                                      +4%                                             -10%    

Open Wheel Sports Car                                     +4%                                             -10%    

Open Wheel Race Car1                                       +8%                                             -20%    

1 except GP race cars

AWD and FWD Cars

AWD and FWD cars require more braking force on the front and a lower brake pressure than RWD cars.

                            Brake Distribution Offset      Brake Pressure Offset

AWD                                    +2%                                             -5%    

FWD                                     +4%                                           -10%    

Mid and Rear Engine Cars

Mid and rear engine cars require higher braking force on the the rear and a higher brake pressure than regular front engine cars. 

                            Brake Distribution Offset      Brake Pressure Offset

Mid Engine                          -2%                                              +5%    

Rear Engine                         -4%                                            +10%    

Differential

Differential is for fine tuning corner entry and exit behaviour. Also a good ratio between accel and decel supports smooth cornering without unnecessary corrections.

 

Generally older cars require lower accel and higher decel than modern cars and race cars require higher accel and lower decel than production cars. Also off-road cars require lower differential settings than road cars.

 

RWD Cars

68/35 is good middle ground for road cars, increase accel and/or decrease decel for cars with more rigid chassis/suspension (i.e. super cars, GT race cars etc.), decrease accel and/or increase decel for cars with more flexible chasssis/suspension (i.e. older cars).

70/34 is good middle ground for high performance cars, race cars and race trucks, increase accel and/or decrease decel for cars with more rigid chassis/suspension (e.g. modern race cars), decrease accel and/or increase decel for cars with more flexible chasssis/suspension (e.g. older race cars).

96/0 is good middle ground for prototype race cars, increase accel and/or decrease decel for modern protoype race cars, decrease accel and/or increase decel for older prototype race cars with more flexible chasssis/suspension.

0/80 is good middle ground for GP race cars, increase accel for modern GP race cars, decrease accel and/or increase decel for older GP race cars with more flexible chasssis/suspension.

38/5 is good middle ground for modern off-road cars, decrease accel and/or increase decel for older off-road cars with more flexible chasssis/suspension.

16/10 is good middle ground for off-road race trucks, increase accel for modern off-road race trucks, decrease accel and/or increase decel for older off-road race trucks with more flexible chasssis/suspension.

Note: For some reasons increasing and decreasing accel only works good in 2-step increments (i.e. accel should always be an even number) while for decel 1-step increments are just fine.

Car Type                                Accel               Decel

Street Car                               64-68%            34-36%

Sports Car                              64-68%            34-36%

High Performance Car           70%                  34%

Race Car                                 68-72%            34-35%

Race Truck                                72%                  34%

Prototype Race Car               94-98%               0%

GP Race Car                                0%                  80%

-----------------------------------------------------------------------

Off-road Car                           36-38%              5-6%

Off-road Sports Car               36-38%              4-5%

Off-road Truck                        36-38%              5-6%

Off-road Race Truck                 18%                 11%

The ranges given account for different body types within the car type.

Open Wheel Cars

Open wheel cars require lower accel and higher decel than regular closed wheel cars to stabilize the car while cornering.

                                                            Accel Offset          Decel Offset

Open Wheel Off-road Truck                  -5%                           +6%

Open Wheel Off-road Car                    -10%                         +12%

Open Wheel Off-road Sports Car       -10%                         +12%

Open Wheel Street Car                        -20%                         +24%

Open Wheel Sports Car                       -20%                         +24%

Open Wheel Race Car1                         -40%                         +48%              

except GP race cars

FWD Cars

For FWD cars use the RWD diff settings as basis and set them according to following scheme:

Front Accel:  RWD Accel - 20%

Front Decel:       0%

AWD Cars

For AWD cars use the RWD diff settings as basis and set them according to following scheme:

Front Accel:  RWD Accel 

Front Decel:       0%

Rear Accel:      100%

Rear Decel: RWD Decel

Diff Distr.:   RWD Accel + 2%

Mid and Rear Engine Cars

Mid and rear engine cars require lower accel and higher decel as compared to regular front engine cars.

                                Accel Offset             Decel Offset

Mid Engine                   -12%                          +20%

Rear Engine                  -24%                          +40%        

Gearing

For general tuning only adjustment of the final drive is required. Tuning single gears ratios is only required when tuning for specific tracks.

Setting up the final drive depends solely on the cars power and the type of installed gearbox. The general logic here is a car with more power requires a lower final drive and vice versa.

There are two types of gearboxes:

  • Standard Forza race gearbox: 6-speed race gearbox with following gear ratios: 2.89/1.99/1.49/1.16/0.94/0.78

  • Custom race gear box (any other race gearbox)

The general principle here is that the installed gearbox is calibrated to the cars stock power. If the car uses the standard Forza race gearbox, the gearing is scaled to a reference car with a stock power of 400hp. If the car uses a custom race gearbox the gearing is scaled to the cars stock power.

Being calibrated means the cars stock gearing is already optimal for the cars stock power. You only have to change the final drive if you change the cars power via engine upgrades. For each 6hp increase over stock power you need to decrease the final drive by 0.01. Likewise for each 6hp decrease over stock power you need to increase the final drive by 0.01

Cars with Standard Forza gearbox and 6-speed sport gearbox

For cars with a standard Forza race gearbox, a 6-speed sport gearbox and a stock final drive > 4.00 the gearbox is scaled to a reference final drive of 4.25.

To get the required final drive subtract the cars power from 400hp (the reference cars stock power), divide it by 6hp, multiply it by 0.01 and add it to 4.25 (the reference final drive).

Example: RWD car, 325hp, stock final drive 4.21
400hp-325hp=75hp
75hp/6hp=12.5

12.5*0.01=0.125
4.25+0.125=4.375 --> Final Drive: 4.38

Cars with Standard Forza gearbox and 5-speed sport gearbox

 

Cars with a Standard Forza 6-speed race gearbox, a 5-speed sport gearbox and a stock final drive of sport transmission > 4.00 the sport gearbox is scaled to a reference final drive of 4.00.

Cars with Standard Forza gearbox and 3- or 4-speed sport gearbox

 

Cars with a Standard Forza 6-speed race gearbox and a 3- or 4-speed sport gearbox use a higher reference final drive for sport transmission.

For cars with a Standard Forza gearbox, a 4-speed sport gearbox and a stock final drive of sport transmission > 4.00 the sport gearbox is scaled to a reference final drive of 4.75.

For cars with a Standard Forza gearbox, a 3-speed sport gearbox and a stock final drive of sport transmission > 4.00 the sport gearbox is scaled to a reference final drive of 4.50.

Low Gearing Cars with Standard Forza gearbox

There are some cars (like the 1953 Chevrolet Corvette) which require a lower gearing than usual. These are all cars with a standard Forza 6-speed race gearbox and a stock final drive <= 3.25.

 

For cars with a Standard Forza 6-speed race gearbox and 5-, 4- or 3- speed sport gearbox and a stock final drive for race transmission <= 3.25 the race gearbox is scaled to a reference final drive of 3.25.

For cars with a Standard Forza 6-speed race gearbox and a 6-speed sport gearbox and a stock final drive for sport transmission <= 3.25 the sport gearbox is scaled to a reference final drive of 3.25.

For cars with a Standard Forza 6-speed race gearbox and a 5-speed sport gearbox and a stock final drive for sport transmission <= 3.25 the sport gearbox is scaled to a reference final drive of 3.00.

For cars with a Standard Forza 6-speed race gearbox and a 4-speed sport gearbox and a stock final drive for sport transmission <= 3.25 the sport gearbox is scaled to a reference final drive of 3.75.

For cars with a Standard Forza 6-speed race gearbox and a 3-speed sport gearbox and a stock final drive for sport transmission <= 3.25 the sport gearbox is scaled to a reference final drive of 3.50.

High Power Cars with Standard Forza gearbox

Cars with Standard Forza gearbox and very high power (>=800hp) that would potentially exceed the available final drive range simply require to half the cars power and do the above calculation.

 

Low Power Cars with Standard Forza gearbox

Cars with Standard Forza gearbox and very low power (<=200hp) that would potentially exceed the available final drive range simply require to double the cars power and do the above calculation. 

Cars with Custom Gearbox


For cars with a custom race gearbox the gearbox is scaled to the cars stock final drive.

To get the required final drive subtract the cars power from the cars stock power, divide it by 6hp, multiply it by 0.01 and add it to the cars stock final drive.

Example: RWD car, 325hp, stock power 300hp, stock final drive 3.30
300hp-325hp=-25hp
-25hp/600=-0.04166667
3.30-0.04166667=3.25833333 --> Final Drive: 3.26

Cars with Custom Gearbox and Homologated Restrictor Plates

A lot of race cars and some high performance cars have homologated restrictor plates that limit the cars stock power to meet the divisions power restrictions. For these cars the reference power is not the cars stock power but the power with installed homologated restrictor plates which is lower than the cars stock power.

Race Cars with no Engine Upgrades

Race cars that don't offer any engine upgrades like F1 cars or IndyCars would never require an adjustment of the final drive since you're always running them on stock power. For these cars you need to reduce the cars stock final drive by 0.75 in order to work best. 

Relevant Car Upgrades

Increasing or decreasing power via engine upgrades requires to adjust final drive to adjust the gearbox to the changed power band.

Also when performing a drivetrain swap on cars with a custom gearbox requires to adjust the final drive since cars with drivetrain swaps will always automatically be equipped with a Standard Forza gearbox which is scaled to a reference power of 400hp instead of the cars stock power in case of the cars custom gearbox (see above). 

Car Property            Change               Effect on Final Drive

Power                         Increase                       Decrease

Power                        Decrease                       Increase

Drivetrain            Drivetrain Swap         Increase/Decrease1

1 Only for cars with stock custom gearbox

Aero

Aero tuning in Forza is the most complex topic as it involves many different factors. As opposed to gear tuning it's almost always required since on most tracks you need adjustable race aero kits to be really competitive.

Lets start with the general pattern on how to setup downforce levels depending on the cars drivetrain:

  • RWD: front max / rear max

  • FWD/AWD (drivetrain swaps available): front max / rear min

  • FWD/AWD (no drivetrain swaps available): front max / rear max

Setting up to specific downforce values depends solely on the cars weight and the type of installed race aero kit. The general logic here is the lighter the car is the less downforce is required and vice versa. If downforce levels are setup too low related to cars weight you will lose traction while cornering. If downforce levels are setup too high related to cars weight the car will become unresponsive and more difficult during cornering.

There are two types of race aero kits:

  • Standard Forza race aero kit: adjustable aero kit with front downforce range 50-100 and rear downforce range 75-200

  • Custom race aero kit  (any other adjustable aero kit)

The general principle here is that the installed race aero kit is scaled (or calibrated) to the cars stock weight. If the car uses the standard Forza race aero kit, the aero kit is scaled to a reference car with a stock weight of 3000lb. If the car uses a custom race aero kit the aero kit is scaled to the cars stock weight.

Being calibrated means the aero kits maximum downforce levels (RWD) or maximum/minimum downforce levels (FWD/AWD) are optimal for the cars stock weight. You only have to change downforce levels if you reduce the car weight via weight reduction or other weight reducing parts. For each 100lb decrease over stock weight you need to decrease downforce levels by 1.

However since possible drivetrain swaps can actually increase the cars weight as compared to cars stock weight there is a headroom of 300lb on top of the cars stock weight before reduction of downforce levels is required. That means for most cars that offer drivetrain swaps you have to reduce the car weight over 400lb as compared to cars stock weight before reduction of downforce levels is required.

Car Property        Change           Effect on Downforce

Weight                    Increase                    Increase

Weight                   Decrease                   Decrease

Power                     Increase                    Increase1

Only in special cases, see below

Cars with Standard Forza Race Aero Kit

For cars with a standard Forza race aero kit you have to subtract the cars weight from 2700lb (the reference cars stock weight - 300lb headroom for drivetrain swaps if available), divide it by 100lb and add it to maximum downforce levels (or maximum / minimum downforce levels in case of FWD).

Example: FWD car, 2900lb, drivetrain swaps available

2900-(3000-300) = 200

200/100=2

Front: 100+2=102 --> 100 (maximum downforce), Rear: 75+2=77

Example: RWD car, 2500lb, no drivetrain swaps available

2500-3000 = -500

-500/100=-5

Front: 100-5=95 Rear: 200-5=195

High Power Cars with Standard Forza Race Aero Kit

Usually only car weight determines required downforce levels but for cars with standard Forza race aero kit and very high power (>=800hp) extra downforce is required to stabilize the car. In this case multiplying the maximum downforce levels (or maximum / minimum in case of FWD) with 1.5 is required before performing the above calculation. 

Example: FWD car, 2900lb, 800 hp, drivetrain swaps available

2900-(3000-300) = 200

200/100=2

Front: (100*1.5)+2=152 --> 100 (maximum downforce), Rear: (75*1.5)+2=114.5 --> 115

Low Power Cars with Standard Forza Race Aero Kit

Likewise cars with standard Forza race aero kit and with very low power (<=200hp) don't require as much downforce as usual. Here you have to multiply front aero downforce with 0.7 and rear downforce with 0.4 after you performed the above calculation.

Example: FWD car, 2900lb, 200 hp, drivetrain swaps available

2900-(3000-300) = 200

200/100=2

Front: 100+2=102, 102*0.7=71.4 --> 71, Rear: 75+2=77, 77*0.4=30.8 --> 75 (minimum downforce)

Cars with Custom Race Aero Kit

For cars with a custom race aero kit you have to subtract the cars weight from the cars stock weight - 300lb (the headroom for drivetrain swaps if available), divide it by 100lb and add it to maximum downforce levels (or maximum / minimum downforce levels in case of FWD).

Example: FWD car, 2500lb, stock weight 3047, maximum/minimum downforce levels 155/158, drivetrain swaps available

2500lb-(3047-300) = -247

-247/100=-2.47

Front: 155-2.47=152.53 --> 153, Rear: 158-2.47=155.53 --> 158 (minimum downforce)

Example: RWD car, 2100lb, stock weight 2745, maximum downforce levels 392/570,  no drivetrain swaps available

2100-2745 = -645

-645/100=-6.45

Front: 392-6.45=385.55 --> 386, Rear: 570-6.45=363.55 --> 364

Cars with Custom Race Aero Kit and High Rear Aero

For cars with custom race aero kit and very high rear downforce (max. rear downforce > 3* max. front downforce)  the rear downforce should never exceed 3*front downforce. Simply cap rear downforce at 3*front downforce.

A prominent example is 1995 Ferrari F50 with a maximum front downforce of 100lb and a maximum rear downforce of 305lb. In this case rear downforce should not exceed 300lb for this car except when tuning for grip tracks which is covered in part 3.

 

High Power Cars with Custom Race Aero Kit

Usually only car weight determines required downforce levels but for cars with very high power (>=1.5*stock power) extra downforce is required to stabilize the car. In this case multiplying the maximum downforce levels (or maximum / minimum in case of FWD) with 1.5 is required before performing the above calculation. 

Example: FWD car, 2500lb, 460hp, stock weight 3047, stock power 306hp, maximum/minimum downforce levels 155/158, drivetrain swaps available

2500lb-(3047-300) = -247

-247/100=-2.47

Front: (155*1.5)-2.47=230.03 --> 230, Rear: (158*1.5)-2.47=234.53 --> 235