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Thread: Setups explained Stolen from Virtual Race Car Engineer

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    Forum Administrator/Game Server Admin -=[FDG]=-Stitch's Avatar
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    Setups explained Stolen from Virtual Race Car Engineer

    Introduction to Springs

    The springs are the foundation of your setup and can be simple to deal with in one sense and difficult in another.
    Springs are primarily used to dictate and control the ride height and body roll of the chassis.
    Springs can also be used to transfer grip to an underused wheel in certain situations such as the example you read about earlier about moving weight to the underused side, or corner, of the car.

    Softer suspension springs will extend the time that your car takes to respond to your inputs.
    This is not necessarily a bad thing.
    A very experienced driver may want the faster response from a stiffer suspension, yet a less experienced driver may need the slower response in order to have more time to react and respond to the car at the limits.
    Neither is really going to be any faster or slower over the course of a lap in equal hands; they are just driven differently.
    For the sake of stability, softer is better. As your abilities advance, trying different spring packages may be worthwhile.

    Using springs to prevent bottoming

    As a rule of thumb, softer springs equal greater mechanical grip and a more forgiving chassis.
    You want your spring package as soft as possible without the car bottoming out from the down force or the bumps in the track.
    We have all seen the images of a Formula 1 car shooting sparks out from the under tray at top speeds.
    This is the bottom of the car hitting the track surface and is the primary definition of 'bottoming'.
    Common sense tells us that when the chassis of the car is making contact with, or dragging on, the track surface you are not reaching your highest possible speeds thanks to that added friction/drag.

    While your car may not be bottoming at slower speeds, your car will likely have added aerodynamic forces pressing the car down into the track at higher speeds.
    These aerodynamic forces can easily exceed the stationary weight of the car, and is a main reason to choose a higher spring rate.
    The springs need to be firm enough to prevent the bottoming, yet soft enough to maximize its mechanical grip when the aerodynamic forces are not there to help you, such as through the slower speed corners.

    There is also another form of bottoming, known as 'bottoming of the suspension'.
    This happens when the chassis itself may not be making contact with the track surface, thanks to bump-stops or packers, but the suspension is compressed to maximum and the spring is prevented from compressing any further.
    If the chassis is riding on the solid bump-stops, there is no suspension movement and the car cannot react to the track surface or weight shifts.
    This may not be an issue on a straight at high speeds but can pose a problem on high-speed corners. Obviously, using bump-stops or packers will allow you to run softer springs with the knowledge that, at the highest speeds, the suspension will be bottoming out.
    You want to prevent, or at least minimize, both versions of 'bottoming' in a stable and predictable setup.
    While it may take some tweaking to find the lowest ride height, softest springs, and amount of bump-stops, you can retain that information for the next track you visit.

    Using springs to preload grip

    Springs can also dictate the amount of grip allocated to each corner of the car, in a generic sense of the term.
    A stiffer spring is 'pre-loading' the grip to that particular corner of the car by pushing the wheel down into the surface of the track.
    The harder the spring pushes, the more grip that is 'pre-loaded' and available in that instant.
    However, while you may have more grip during the initial weight transfer phase, you approach and exceed the point of overloading that wheel's ability at a faster rate.
    Think of this as a glass of water that is partially filled.
    The level of pre-loaded water equals the level of grip ready to be used in an instant.
    The more water pre-loaded the faster it will respond to your inputs.
    However, the sooner it will reach full capacity and exceed it’s limits (spilling over).

    Using springs to corner weight

    Changing the springs at each corner changes your corner weight.
    The car's weight is a constant, it is not changing, but springs can alter the weight at which each wheel is being pushed down into the track surface.
    As you are navigating a corner at full potential of the car and tires, the outside tires will be using their full amount of grip.
    Any additional weight on those tyres will result in a loss of grip as the lateral weight exceeds the capability of the tyre.
    Corner-weight techniques can help spread the workload across all four tyres, offering more overall grip in specific corners where you may be braking or accelerating and cornering simultaneously.
    Just like the weight discussion before, we can pre-load that weight to underused tyres using springs.

    Lime Rock Park is an example of a track that you might have different springs on the left and right sides of your car.
    Since Lime Rock has all but one right-hand corner, you can focus solely on the right-hand turns.
    Having stiffer springs on the right side of the car will allocate more grip to the inside tires, and in turn the inside tyres are sharing more of the workload.
    Again, you will be sacrificing grip in that single left-hand corner of course.

    For the most part, you do not have to be overly concerned with corner-weighting your setup.
    Focus on a symmetrical and balanced spring package and come back to corner-weight techniques later down the road when you have exhausted all other setup options.

    Springs and Aerodynamics

    With all of that said, there are differences in tracks themselves that may force you to adapt or evolve your setup for a specific track.
    A high-speed track may require slightly stiffer springs due to the added aerodynamic forces being generated at higher speeds.
    All-out speed may be more important than grip, so you may wish to sacrifice mechanical grip in exchange for less drag.
    A low-speed track will not generate the same aerodynamic forces, and you rely even further on mechanical grip.
    This may cause you to run an even softer spring package than normal, but since the top speeds are lower, so are the aerodynamic forces that may cause bottoming.
    Cars that rely heavily on aerodynamic grip may sacrifice mechanical grip by using stiffer springs and even lower ride heights.
    The under-body of these cars generates massive down force, and the closer it is to the track surface the greater down force it is generating without the added drag that an increase in wing angle may bring.

    Using springs to balance a car

    Now you can use springs to adjust your setup to your personal needs.
    Typically, for rear-wheel drive cars, the rear springs will be softer than your front springs to maximize rear grip under acceleration.
    Your front springs can be adjusted to balance the grip between the front are rear of the car.
    If the setup is causing understeer, try softer front springs (or stiffer rear springs) to shift some of the grip forward.
    If the setup is causing oversteer, try stiffer front springs (or softer rear springs) to shift some of the grip rearward.

    When you are first developing your baseline setup, use the softest springs available on the rear of your car for maximum grip under acceleration, then balance the front springs to match grip between front and rear for a neutral setup.
    You may find yourself increasing those rear spring rates over time, but it is a good starting point.

    Exercises
    With any exercise, use a car and track combination that you are already comfortable with.
    You may already have a baseline setup that you know well.

    Exercise 1: Increase front springs to their maximum setting and run a few laps.
    Notice the understeer tendencies in the corners?
    Now try the lowest spring settings.
    Notice the oversteer?
    Do the same with your rear springs and feel those changes.
    Work on altering only the springs to re-balance the setup.

    Exercise 2: Choose a specific corner on your chosen track.
    Now pre-load some grip into the inside front spring by increasing that spring only.
    As you approach that corner on track, notice how the car will react as you turn in, apex, and exit that corner.
    Try not to spin thanks to the added front grip.

    Introduction to Antiroll bars

    An antiroll bar is used, just as the name implies, to resist roll while cornering.
    Roll will exaggerate weight shift, alter the camber and caster geometry, and wreak havoc on the aerodynamic forces that the underbody of the car may be generating.
    The larger/stiffer the ARB, the less body roll.
    However, this does not necessarily mean that less body roll equates to more grip.

    The antiroll bar attempts to reduce body roll by pulling the inside wheel up, towards the sky, into the wheel well of your car when going around a corner.
    By pulling that wheel up, the chassis of the car can stay more level to the track surface.
    However, that inside wheel being pulled up and off the track greatly reduces the grip that wheel is generating.

    As a general rule, a softer ARB will equal more grip to that end of the car.
    This is probably the easiest setup adjustment to make to regain a neutral car feel.
    While it may be very common for some to run very soft ARBs, or even completely detach the rear ARB, it is always wise to test the full spectrum.
    Personally, I have found that some vehicles will respond better to the less body roll of very stiff ARBs, and others prefer softer ARBs.
    This, you will have to find out yourself through testing.

    After changing your ARB settings, recheck each of your tire temperatures and make pressure changes as needed.
    You may need to adjust camber and caster settings as well.

    Exercises
    With any exercise, use a car and track combination that you are already comfortable with.
    You may already have a baseline setup that you know well.

    Exercise 1: Increase the front ARB to the maximum setting and go on track.
    Notice the understeer?
    Reset and try the maximum setting on the rear ARB.
    Did that make you spin out at the first corner?
    Re-balance the setup by using only the front and rear ARBs.

    Introduction to weight

    Weight is generally considered as a bad thing in auto racing.
    Sure, the heavier your car is the slower it will be over the course of a lap, but weight is something that can be managed and even used to our benefit.
    There is a silver lining; all of your competitors have to deal with the same amount of weight in their cars.
    The difference is who most effectively uses that weight to their advantage.

    In a sense, weight equals grip: the vertical weight pressing the tyres into the tarmac gives your tyres grip.
    However, too much lateral weight (which varies by the G-force) will cause the tyres to exceed their grip levels determined by the vertical weight.

    Example: A dragster puts as much weight as possible on the rear tyres, the only tyres that really matter in that form of racing.
    Having all the weight to the rear will push the rear tyres firmly into the track, vertically, offering the most grip to those tyres.
    However, if that car was to attempt to race around a corner, the excessive rear weight will cause the rear tyres to exceed their lateral grip capabilities and the car will spin out.

    Any race car that navigates a corner has to deal with weight at all four corners of the car.
    We do want ideal straight-line grip to the rear tires, like our dragster above, but we also need the car to make it around the corners as quickly as possible.
    Being able to adjust the weight bias forward and rearward can help us achieve both of these goals.

    Front to Rear weight

    Generally speaking, an ideal road racing car will have 50/50 weight on the front and rear.
    This makes for a "balanced car" that will neither oversteer nor understeer around a corner.
    That “balance” simply means that both the front and rear tyres lose grip at the same time, making the entire car slide together, not just the front or rear.
    This balance allows a driver to push harder with more comfort, in turn going faster around the lap.
    However, once we start accounting for how G-forces play with the weight of the car, you may want something other than the even 50/50 split.

    For example, when on the brakes leading up to a corner, the front tyres are dealing with a lot of weight shifting forward.
    The tyres may already be at or near their maximum allowable grip due to braking.
    Add in corner affects and they begin to lose grip and start sliding.
    The more weight you shift rearward in your car setup, the less burden on your front tyres in this situation.
    Also consider the exit of the corner, where you begin to act as that dragster in the previous example; where do you want the weight?
    On the rear tyres.
    The more weight shifted to the rear of the car allows for better cornering speeds and better acceleration out of slow speed corners.
    The down side is that the rear of the car may become less stable in higher speed cornering.

    Side to side weight

    Left-to-right weight changes can also be used at specific tracks with predominate left or right hand corners.
    An example of this type of track is Lime Rock Park where all but one corner is to the right.
    In that case, it may be wise to adjust the car's weight to the inside tires (right side) which are underused when in the right hand corners.
    This offers them better grip in those corners thanks to the extra vertical weight applied to tyres that are not at their grip limit.
    Keep in mind that this comes at a sacrifice of the one left corner.
    Oval racers put as much weight to the left side of their cars, as their oval tracks are left turn only tracks.
    The right-side tyres will begin to exceed lateral weight thanks to the cornering G-forces, while the left side tyres are underused and in need of more vertical weight to share the load between the left and right-side tyres, and offset the weight transition and roll of the car while cornering.

    TIP: Keep in mind that as fuel is consumed during a race, most cars will lose rear weight at roughly 8 pounds for every gallon of fuel burned. This will have an affect on your car’s handling over the course of a fuel load.

    Using weight to balance a car

    Exercises
    With any exercise, use a car and track combination that you are already comfortable with.
    You may already have a baseline setup that you know well.

    Exercise 1: Take a car out on a favorite race track that you already have some knowledge of.
    Increase the car's front weight and go out for a few laps.
    Take notice of how different it feels in the corners.
    Return to the garage and remove that added front weight and place it to the rear.
    Go out again and take notice of the difference in feel.

    Exercise 2: Take the car out again but on a track that has corners predominately one way or the other; Lime Rock Park is a great example.
    Move the weight to one side, feel the changes on track, then do the opposite again.

    Introduction to tyres

    Tyres are the contact between our vehicle and the track surface.
    The contact patch of the tyre is literally the small patch of rubber that is making contact with the road surface.
    It is usually no more than a few square inches at a time.
    Because the contact patch is so small, every tiny bit of additional contact patch is worth more grip than any other adjustment you can make to your car.
    Tyres are easily the most important aspect of your setup, and one you will always go back and check after each and every other setup change.

    Optimizing tyre pressures

    All tyres are designed to operate at an optimal temperature.
    Exceed that temperature and you begin to lose grip.
    Do not achieve that temperature and you never achieve the maximum grip level of the tyre.
    For this example let's say 200 degrees Fahrenheit is our ideal temperature.
    In a perfect world all four of our tyres would be at 200 degrees at all times, but this is not realistic.
    Each tyire is going to have different temperature readings depending on camber, caster, toe, springs, antiroll bars, and tyre pressures.
    Every adjustment you make to the other chassis components will require you to retest and adjust your tyre pressures in a never ending quest to find the most optimal temperatures you can achieve.

    It is widely accepted that in a road racing setup the inner temperature of your tyre will be the hottest (thanks to negative camber, which we will discuss shortly) with the middle being next in line and the outer temperature being the coolest of the three.
    This is because the camber dialed into the setup causes the outside shoulder of the tyre to be used less over the course of a lap.
    Many use a 10-15 degree spread as a target to aim for as in the example below:

    (Outer, Middle, Inner)
    185 192 200

    While this is a good starting point, these settings are not a true optimization of your contact patch.
    The first question you must answer is,
    "Where are these temperatures happening?"
    Reading temperatures after a straight does not give a true representation as to what the tyre is doing in the corners.
    The tyres need optimal contact patch at the corners, not in the straights.
    You must get your readings as soon after a corner as possible, and the tyres must be at full pressure.
    This means to optimize just one tyre you will need to complete multiple laps to get that tyre up to full operating pressure before approaching the corner that you plan to get your reading from.
    On the same note, the corner that you choose should be the corner that generates the most heat in that specific tyre.
    This may be a different corner of the track for each tyre.

    What you are looking for is not a simple 10 or 15 degree spread, but the same temperature across all three points of the tyre while in the corner.
    If the inside is 200 degrees, then the outside should also be at or near 200 degrees, and the middle should also be nearest to 200 degrees as possible.
    You certainly will not want the outside temperatures higher than the inside temperatures, so you will end up with the outside slightly cooler in most instances.
    The middle temperature is at its optimum if directly between the inner and outer temperatures, as shown below:

    (Outer, Middle, Inner)
    195 198 200

    Camber is your primary weapon to achieve a uniform inner and outer temperature of your tyres.
    Air pressure is what you will use to fine-tune the middle temperature.
    Increase air pressure to increase the use of the middle band of the tire, in turn increasing its temperature.

    Tyres and spring rate

    While I have been talking specifically about the contact patch of the tyre, there is another part of the tyre that you should keep in mind: the sidewall.
    While the sidewall does not make contact with the track, it is still a vital piece of your setup equation... as a spring.
    A tyre is basically a balloon, and a balloon is a spring in every sense.

    As you optimize your tyre temperatures, you are inadvertently changing your well laid out spring setup on your car.
    One pound of air pressure can be equal to 15–25 lbs of spring rate, meaning you may now need to go back and adjust your corner springs to achieve that neutral feel again.

    And now that we know that piece of information, we can use tyres — just like we did with springs — to preload grip to underused tyres.
    Want a little more front-bite on that left hand corner in the middle of a race? You can add a bit of PSI to that left-front tyre to give it an additional share of the grip between the two front tyres.

    Reading tyres properly

    Tyres are a great way to read your overall setup package and driving style.
    If your front tyres are hotter than your rear tires then you may need more grip to the front of the car, either mechanical or aerodynamic.
    You could just as easily remove grip from the rear to balance the front-to-rear temperatures.
    A front-to-rear difference in tyre temperatures can tell you not only if your setup is balanced, but also if your driving is good or bad.
    Sliding the car around will bring higher temperatures and can explain a difference in tyre temperatures.
    Adjust your driving as needed.

    Slip Angle

    A tyre will never achieve optimal grip without some degree of slip.
    The amount of this slip is measured in degrees and is known as "slip angle".
    If the radius of a corner is 80 degrees, you will want your tyres to be on an arch of a few degrees more.
    Four to eight degrees of slip will actually produce more grip than zero degrees of slip.
    Exceed the optimal slip angle and you lose grip.
    The 'slip' causes the rubber of a tire to squirm and flex.
    The laws of physics say it will want to return to its normal form.
    This returning action causes a 'suction' of sorts to the road surface.
    Upon contraction of the rubber back into its static form, it pulls the tyre, and car, into a tighter turn.
    Keeping your tyres in the optimal slip angle is the difference between a fast driver and an alien driver.
    This is all done by feel and experience, as there is no display in our cars to inform us that we are in that slip angle sweet spot while driving on the track.
    Experience is the only way to achieve this, and having a balanced and comfortable car is paramount.

    Using tyre pressures to balance a car

    Exercises
    With any exercise, use a car and track combination that you are already comfortable with.
    You may already have a baseline setup that you know well.

    Exercise 1: Increase both front tyres to their maximum and go on track.
    Take note of the newly added understeer associated with the extra spring rate of the tyres.

    Exercise 2: Choose a specific corner on the track you chose for this exercise.
    Now pre-load some grip into the inside-front tyre by increasing that tyre's pressure only.
    As you approach that corner on track, notice how the car will react as you turn in, apex, and exit that corner.

    Toe

    Toe is known as either toe-in or toe-out.
    It is measured by the angle at which the two wheels are pointing in/out from each other, as seen from above, like a duck's feet.
    Toe plays an important role in your car's straight line stability as well as its cornering characteristics, especially the initial turn-in phase of a corner.
    A standard passenger car has some toe-in built into the alignment for stable straight line driving.
    This toe-in is what allows you to let go of the steering wheel in your passenger and the car will continue to travel in a straight line.

    Toe-in will induce understeer in the corner as both wheels are pushing inwards and fighting against each other to maintain that stability.
    Toe-out will reduce straight line stability, quite possibly to the point of the car slightly wandering left and right when trying to drive a straight line.

    Let us forget about driving on the street, we are racing here!
    Front toe-out offers more grip while turning as the tyres are not fighting against each other.
    Imagine both front wheels pointed away from each other slightly (Toe-out).
    Now imagine what happens to those tyres when you are in a corner; the outside front is following a track around the corner at a slightly longer radius.
    The inside tyre has a tighter radius corner to navigate, so it actually needs to be turning slightly more.
    Toe out gives this to us, and is known as Ackerman's Effect.

    It can be argued that any amount of Toe (in or out) adds friction and drag, slightly reducing your top speeds, or at least how quickly you get to your top speed.

    Caster

    Caster is the angle of the car’s front suspension as seen from the side.

    An example of positive caster is that vintage chopper motorcycle where its steering axis is reclined, or "raked", at the angle of the motorcycle's forks.
    An example of negative caster (never ideal in racing) is the front wheels of a shopping cart.
    They are being dragged behind the steering pivot point, often wobbling around and very unstable.

    More positive caster has the effect of more self-centering of the steering when in a straight line, which can be a good thing for comfort alone.

    Caster effect on camber
    Caster also affects the camber of both tyres when the wheels are turned, and does so in a degree relative to the steering angle.
    The more you steer, the greater you are changing the camber of your front wheels.
    More caster built into your setup gives more negative camber to the outside wheel when in a turn, allowing the option of less static camber built into your setup and using more caster to achieve your ideal camber angle.

    Just as important is how positive caster affects the inside wheel camber.
    The inside wheel will lose some of the negative static camber and possibly even go into a positive camber setting which is ideal for your inside wheel while in a corner as noted in the oval racing setup discussed above.
    The more static negative-camber you can replace with caster the better your front wheels will maintain grip in straight-line actions, such as braking or accelerating.

    Introduction to camber

    Camber is the vertical angle of the wheels in degrees — with zero meaning straight up and down — as viewed from standing in front of the car.
    If the top of the wheels are angled in towards each other, this is negative camber. Road racing setups will use negative camber on both front tires, but oval racing setups may see the inside front tyre (usually the left-front) with a positive camber setting.
    More on that in a bit.

    As weight, weight transfer, or aerodynamic forces press that corner's suspension firmly into the surface of the track, the car rolls, and so do the suspension points on that car.
    Ideally, when in a corner, the negative camber built into the setup will transition positively as the chassis rolls, causing the tyre to achieve a near-zero camber as compared to the track surface.

    Once again, camber is the primary weapon you have to achieve uniform inner and outer tyre temperatures.
    Air pressure is what you will use to fine-tune the middle temperature.
    Since you are now taking your readings during times that the tyres are being used the most, you will be able to optimize your contact patch more effectively.

    Camber in oval racing

    Oval racing requires a very different setup than road racing thanks to the very specialized track layouts.
    Ovals have predominately left hand corners, so let's consider how camber should be used in that setup process.

    Imagine what is happening to the oval racing car when traveling through a left hand corner at high speed; the right side is being crushed under all that weight transfer, and the left side of the chassis is rising into the air.
    The right side, which would likely have negative camber built into the setup, will approach closer and closer to zero-camber when compared to the track surface.
    However, the left side will do the complete opposite.
    The chassis is rolling toward the sky, changing the camber of that tyre in the opposite direction; more to the negative angle as compared to the track surface.
    In effect, that inside tyre could be riding on a razor-thin shoulder of the tyre with the majority of the tyre surface not in contact with the track surface at all.
    To circumvent this, an oval setup may have positive camber built into the left-side suspension geometry.
    As the car rolls, that geometry transitions further and further negative until, once again, a near zero camber is achieved.


    Camber in road racing

    As stated in the paragraphs on tyres, it is very important to maximize the contact patch of each tyre.
    When a tyre is leaning inward, part of that tyre (the outside shoulder) is not making contact with the racing surface and reducing potential grip.
    However, you will not be driving in a straight line at all times, so you must design your suspension so the tyres achieve peak grip while the grip is actually needed... in the corners.
    Camber adjustments allow you to plan ahead so that contact patch is in full use when it is most needed.
    You do this by looking to achieve 0 degrees of camber angle when in the corner. This requires some static negative camber to be built into a setup.

    Dialing in some degree of static negative camber anticipates the camber change due to weight shift while cornering.
    You may not have an optimal contact patch when your car is at a standstill, or even on a straight, but once again the goal is to maximize cornering grip.
    Your tyres will inform you of the proper amount of camber when the inner and outer temperatures are near equal while cornering.

    While negative camber assists only your outside wheel in a corner, it has a negative effect on the grip of your inside wheel while cornering, and on both wheels while braking or accelerating.

    Introduction to gearing

    Gearing is our first "black art" subject.
    Proper gearing is often overlooked to the point of blatant neglect by many.
    We usually set our top gear to what is needed for the longest straight and evenly gap the remaining gears.
    This will do the trick of course, but neglecting the optimization of your gearbox means you are losing time out on the track.
    How much time?
    Easily a second or more on an average sized road course.
    This time can be gained with no added effort on track, just in the garage.

    Engine torque and gearing
    The first step in the process is to determine the RPM range at which the engine is at peak power.
    We want our engine to be operating in, or at least very near, that peak power range.
    Power is usually defined by the common term “horsepower”.
    However, horsepower is a fictitious number based on torque and RPM.
    It should not be used as the sole rating of power.
    Simply put; Torque is what propels the wheels.
    Horsepower maintains that motion.
    You are better to go straight to the source and look at the torque numbers of a motor.
    Find the RPM range that your engine delivers peak torque, and let us use that.

    The engine's peak torque will remain the same no matter the gear you are in.
    What truly creates forward motion is that torque being delivered to the drive wheels, and then in turn being delivered to the racing surface.
    The more torque you can deliver to the drive wheels, the greater the force propelling you forward.
    Here is your daily epiphany that most overlook; drive-wheel torque can be changed by gearing.

    Consider gears as an engine-torque-multiplier.
    The higher the gear ratio, the higher you are multiplying the torque from the engine to the drive wheels.
    This is why it is easier to accidentally spin your tyres in first or second gear than others.

    Remember your old 10-speed bicycle? Put it in first gear and pedal away as fast as you can.
    The end result is that you accelerate quickly. Now place it in the 10th gear and try again... much slower acceleration.
    The engine (your legs) are producing the same amount of torque no matter what gear you are in, but the gearing has changed the amount of torque being delivered to the rear tyre.
    First gear will always deliver more torque to the rear wheels then second gear even though the engine is not delivering any additional power.

    Avoiding unnecessary gear changes

    Also, you are looking to avoid any unnecessary gear changes, and especially looking to avoid any gear changes while cornering or accelerating out of a corner.
    Any time you have to shift up to the next gear, you are not accelerating forward for that fraction of a second.
    While it may only take a quarter-second to complete an up shift, what would you do to shave a quarter second off your lap time?
    Eliminating unnecessary up shifts is a very simple way to do just that.
    If you know you are going to be forced into an unnecessary up shift, think about how you can do this when your foot is going to be off the throttle anyway, such as when you are braking or at corner entry.
    That is the time to put the car in the correct gear, not mid-acceleration.

    Optimizing gear ratios

    So now that we know what we are looking to optimize, we can set out to do just that.
    Start by setting your top gear so you do not hit your rev-limiter at the end of the longest straight on the track.
    Set it to a point that you achieve maximum safe engine RPM just before braking.

    You will now have to decide what purpose your first gear will have for this race.
    Does the track have a hairpin turn that may require a low gear selection?
    Is the event standing or rolling start?
    Are pit stops required?
    These questions will help determine the use of first gear.
    Generally, if you car is going to be at a standstill for any reason you will want to reserve first gear for that reason alone.
    Whether it is a standing start or pit stops, set your first gear for maximum acceleration from that dead stop.

    If you do not have to deal with your car being at a standstill during the race, then tune the first gear to the slowest corner of the track, or the speed of your formation lap speed for that rolling start.
    You are looking to have your engine RPM just beginning to enter the point of maximum torque at the exact time you are planning to accelerate from those lowest speed.
    If your peak torque is at 5500 RPM, then 4500-5000 RPM is a good target to shoot for as you are exiting that slowest corner or start the race.
    The goal is to exit the corner fully and still have a few RPM left to accelerate in a straight line before having to change to the next gear.

    If you are in second gear then you are not using the full potential of the torque that can be delivered to your drive wheels.
    If you are already near maximum engine RPM in first gear, you will be forced into an untimely gear change costing time while everyone else is pulling away.

    All gears in between your first gear and your top gear need to be optimized for the corner in which that specific gear will be used.
    You will optimize a gear to each corner on the track so you are at the best RPM to accelerate threw, or out of, said corner.
    Ideally, you will have another second or so of maximum torque prior to having to change to the next gear.
    This will maximize your acceleration out of the corner and onto the straight following it.
    You may not have evenly spaced gears any longer, but you will be accelerating faster out of each corner and lap times will fall without any extra effort on your part.
    You may even find that you are traveling at such a higher speed that your top gear is no longer enough and it too needs to be extended.

    Understanding the diff

    First, some terminology clarification:
    As I refer to a 'tighter' differential, I will be referring to an increase in the differential value. 'Looser' will refer to a decrease in value.

    You must first understand what the diff does before you can start adjusting it;
    In modern cars, the two rear drive-tyres are not connected by a solid axle.
    They are allowed to rotate at different speeds than each other thanks to the differential located between the transmission and the rear wheels.
    The looser the differential, the more independently the rear tyres will be allowed to rotate.
    The tighter the differential, the more they will want to rotate at the same speed.

    A very loose diff will allow the inside and outside tyres complete freedom to spin at different speeds.
    This is helpful in the corners, but can induce both oversteer and understeer for different reasons.
    When you begin to lose traction with a very loose power- differential setting, all drive power is redirected to the wheel that has lost grip, usually the inside wheel.
    This prevents the outside wheel from losing any more grip and hopefully prevents you from spinning.
    Our standard passenger cars usually come with a 15-25% diff setting for this very reason... it is safe.

    A loose differential may be preferred in some corners where you need to be on the throttle while still deep in the corner (the final corner at Monza - Parabolica - is a prime example).
    Having too loose of a differential may cause your inside drive wheel to break traction and begin to spin.
    You cannot accelerate forward while this is happening, so limiting it from spinning is important.
    It may also lead to oversteer if begins to spin as it is increasingly more difficult to regain the grip to it the longer it is spinning, causing more and more oversteer until you are finally facing the wrong direction.

    A tight differential setting increasingly prevents the inside and outside tyres from independent rotation.
    This will force the rear wheels to share the workload more and is more suitable for straight line acceleration, such as exiting a tight hairpin or chicane.
    The downside is that when you begin to lose traction on either of the wheels, it forces the other tyre to begin to lose traction too.
    While a tight differential may be preferred for the hairpins and chicanes, having too tight a differential setting can result in understeer as both rear wheels are spinning at or near the same rate when navigating longer corners.
    The tighter setting causes the inside rear wheel to push the car into a straighter line, causing understeer. It can also induce oversteer as once you begin to lose traction on either of the wheels the other is certain to follow and a spin is not too far away.

    A dragster will have a very tight diff (completely locked axle) as a dragster only needs to focus on straight line acceleration and not any cornering at all.

    As a rule of thumb;
    A loose differential is easier to drive as long as you can manage that inside tyre from spinning up.
    It will be more forgiving to accidental loss of grip, but you can easily lose time if that inside tyre is preventing you from accelerating.
    A tighter differential can be less forgiving as you will feel more snap oversteer with little time to recover from it.
    Still, having both wheels working together can be beneficial as it will maximize your acceleration out of the tighter corners, but you will have to manage the understeer and snap tendencies in the longer corners.

    You need to know why the car is under- or oversteering before you can make any diff changes.
    Is it spinning up that inside tyre?
    Is the loss of grip to the outside tyre causing the inside tyre to also lose grip?
    Is there too much grip to that inside tyre?
    These are the questions you need to be asking.

    If the track you will be racing on has numerous long, fast, sweeping corners (Barcelona is a great example), then your setup may benefit from a looser differential setup.
    If the track is chocked full of chicanes and hairpins (Monza or Montreal) you may want to consider a tighter diff setup to focus on the straight line acceleration and braking.
    As usual, there is no perfect setting and you will just have to test different settings to find what is comfortable to you.

    Power and Coast settings
    Power and Coast settings are as they appear.
    The diff settings are adjustable for either when you are on the throttle when accelerating out of a corner (power), or off the throttle when braking or slowing for a corner (coast).

    Differential preload
    The preload settings are fairly straight forward.
    The higher the value, the greater the diff is preloaded - or "prepared" - for the transitions between power and coast.
    If the car is very twitchy or overreacts as you transition on/off the throttle mid-corner, you may wish to reduce your preload.
    If you can handle a little twitchiness, added preload can help you adjust the car's attitude, with only minor throttle adjustments, as you work through a longer corner.

    Reducing aerodynamic drag

    If you are confident that you have achieved all the mechanical grip possible, and a balance in high speed corners, then you can put some attention into reducing the drag if at all possible without sacrificing your overall lap times.
    Before making any changes, run a few more laps on the setup until you feel you have reached a good benchmark lap.
    Return to the garage and reduce both the front and rear wings by an equal percentage (to keep your aero-balance).
    Small amounts are good to start with.
    While you may not feel a big change your lap times will show if you are headed in the right direction.
    Continue refining your aero package until you no longer see any further gains.

    Keep in mind, you only want to carry as much wing (drag) as is needed.
    Having more wing in place then is truly needed is slowing you on the straights, and that is where the passing takes place in a race.
    Pick the most-important high speed corner, or sequence of corners, and carry only enough wing to safely and comfortably navigate through those corners.
    Once complete, your car's gearing may require a change, as may ride height, camber, tyre pressures, etc.

    Introduction to dampers

    Dampers counteract the springs natural compressing and decompressing by resisting those forces.
    Dampers do this via hydraulic fluids being pushed through small valves inside the damper while it is in motion.

    A wheel's maximum grip level will be achieved when the spring is fully compressed.
    This is when that wheel has maximum vertical weight being transferred through the suspension, to the tyre, and then to the track.
    How quickly or slowly that spring is allowed to fully compress or decompress is the job of the damper.
    Springs may dictate how much weight is transferred; dampers dictate how and when that weight is transferred.

    The easiest way to begin to understand dampers is in a straight line, under braking and/or acceleration only.


    Diagonal damping

    'Diagonal' damping is where things start getting a bit more complicated, and interesting.
    Imagine what is happening to the right-front suspension of your racecar as we go barreling into a left turn.
    As you lift off the throttle and apply brakes the weight of the car is being shifted from the rear of the car to the front.
    Add to this a left-to-right weight shift as you begin to turn in to the corner.
    The right-front spring will compress under the weight transfer, and the damper will do the same.
    A low compression setting will allow that spring to compress quickly, giving that tyre its full available share of grip very quickly.
    A higher compression setting will force the spring to compress more slowly, meaning the weight of the car will not transfer as quickly and maximum grip will still be available, just slightly later in the phase of the turn.
    The spring will fully compress no matter what the shock’s compression setting is, but you can dictate when during the corner, and that is extremely important.

    Now for the fun part;
    In the above example the opposite is happening to the left-rear of the car as it is losing weight both from braking and turning.
    That spring and damper is in a rebounding phase.
    How quickly that suspension is allowed to rebound dictates the grip for that wheel during this transition as well.
    If the shock is set to a low rebound setting then the spring will be allowed to easily decompress and maintain maximum grip.
    If set to a higher rebound, the spring will not be allowed to rebound as quickly and the grip will be reduced as the wheel is being pulled off the racing surface.
    You can imagine how this might affect the car during this corner-entry phase and how you can adjust it to suit your driving style.
    Either diagonal corner can be adjusted to accomplish the same goal.

    As the car approaches the middle of the corner, the springs are already at full compression and/or rebound, and the dampers would be as well.
    Dampers do not play a role in the handling of the car once this has occurred, as dampers need to be in motion to function(either compressing or rebounding).

    As we pass the point in which the car is at a settled state in the middle of the turn, you begin to apply throttle for maximum exit speed.
    Applying the throttle will shift weight to the rear of the car, and as we ease out of the steering the weight will begin shifting back towards the left.
    As you apply throttle the right-rear shock begins to go into more compression, though it may already be near its maximum compression thanks to the cornering forces.
    Since we can’t make this spring and shock compress any further, actions can be taken from the diagonal corner (left-front).
    Altering how that spring deals with the weight shifting will increase or decrease overall front grip and may offer a better corner-exit balance to your setup.

    There are hundreds of variables in dampers, even though there are only four dampers on the car.
    Changing one will alter the other three as well.
    One adjustment to the right-front rebound will alter how the weight is shifted to the left-front wheel (Lateral weight transfer in quick succession turns like chicanes or long sweepers), the left-rear (diagonal weight transfer in corners while braking or accelerating), and the right-rear (Longitude weight transfer under braking and acceleration).
    You have to be aware how one change will affect the other aspects.
    As usual, any setup change is a compromise between a gain in one area and a loss in another.

    Fast dampers

    If your car is equipped with fast-damping adjustments, everything above still applies but only when the suspension is in fast-motion.
    Normal driving, or racing, equates to slow-damping.
    An example of your suspension moving in fast-motion is when you are hopping over curbing.
    This is when you are shocking the suspension into movement in a very short time frame.
    Hitting a curb at speed (like you might at Monza) forces your suspension to compress or rebound in a much shorter time frame than normal weight transitions.
    This is where fast-damping comes into the mix.

    How could you use fast damping to get your car to hop those curbs and stay planted to the track? How about a soft fast-compression setting to allow the suspension to quickly adjust to the initial impact to the curb?
    Or how about a stiffer rebound setting so once you do come back to earth from being airborne, the car resists the urge to bounce back into the air?
    There are a lot of factors that you can play with to find your perfect feel while curb-hopping.

    All of the fast-damping applies to rough surface tracks as well, especially rough portions of track that you may hit at a high speed.

    Side to side damping

    The same philosophy can be applied laterally (side to side) as well.
    Long sweeping corners that do not involve large braking or accelerating will shift weight to the left and right of the car.
    How fast you allow that weight to transfer is up to you and can be adjusted via the left and right side dampers, but keep in mind how that will also affect your front to rear damping.

    Dampers under acceleration

    Under straight-line acceleration the complete opposite is happening, with the rear dampers compressing and the front dampers decompressing.
    Surely you will want maximum grip on the rear tyres under acceleration, but the front tyres may still need their share of grip adjustment to prevent understeer or oversteer at corner exit.
    You can adjust this condition by adjusting how quickly the rear suspension compresses or how quickly the front suspension rebounds in the same manner we discussed regarding braking.

    Dampers under braking

    Under braking, much of the car's weight will shift from the rear of the car to the front.
    The front springs will compress while the rear springs will decompress (or rebound).
    The dampers do the same and will compress (front) and rebound (rear).
    The faster the front springs are allowed to achieve that weight shift, the faster the front tyres will have maximum grip for the all important braking.
    A lower compression setting will give the least amount of resistance to the spring compressing, allowing weight to transfer very quickly once the brakes are applied, if that is what you want.

    While the rear damper compression setting will have no effect on what happens under braking, the rear rebound setting will.
    A higher rebound setting will resist against the rear springs decompressing.
    If the spring is not allowed to rebound as quickly as the weight is shifting, the rear tyres will be somewhat lifted off the ground (I am exaggerating to show the point).
    Softer rebound settings in the rear will allow the rear tyres to stay more connected with the road and offer more rear-grip during that weight transfer to the front.

    Imagine how you could adjust either your front damper compression settings, or rear damper rebound settings, to achieve a more balanced car when slowing and cornering at the same time.
    In effect, you can choose when the front gets to maximum grip and when the rear loses some grip, both of which can assist a more comfortable turn-in for that corner.
    Last edited by -=[FDG]=-Stitch; 11th-June-2018 at 05:28 PM. Reason: Readability, Spelling

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