Daunt
MLG Pro
So as we get more and more into making and tweaking our own setups I thought it wise to share basic fundamental knowledge of how a race car works, each component, to get a better understanding of how to set the car up. With this, you can really understand what might need to be tweaked in car and really understand, when you move something 1 or 2 clicks, is really happening.
I'm taking a lot from a couple books in racecraft I've read, namely "Ultimate Speed Secrets: The Complete Guide to High-performance and Race Driving" from Ross Bentley as well as "Going Faster! Mastering the Art of Race Driving" by Carl Lopez and Danny Sullivan. Another excellent source is http://iracing.wikidot.com/ which acts as a great setup wiki for iRacing.
I'm also drawing some new knowledge from Drivers University, from Driver61.com.
Part 3: Balance & Weight Transfer
Finally getting around to writing this part 3. First I'm going to talk about what happens with balance and weight, and then follow up with various ways you can affect balance with car setup and driving style. The car setup portion will fit in nicely with part 1, where I gave very basic overviews of how the car's suspension works. It might also make a good segway into the next part.
First and foremost, a car's grip is determined by a great many things - tires, weight, the track, temperature, etc. However, this grip can vary depending on what the car is doing. Weight is the primary role in how much grip you'll have at any given time on track, whether you realize it or not. The more weight on a given tire, the more grip it has; and vice versa. That's why if you're understeering mid corner, you can let off the gas a bit to move weight forward so you get more front grip to turn. But don't go thinking you can just put more weight everywhere because it doesn't offset having to accelerate, decelerate and maneuver with all of it. So you have to work with what you've got.
All weight transfer occurs around the car's roll center and the terms associated with the specific weight transfer all describe what is going on. At rest, or at a constant speed (and direction), a car is evenly balanced.
For the purpose of this walkthrough, I will assign each tire a "grip number"... so the higher the grip number, the more grip.
You can see here, at rest / at constant speed, the car gets 25 grip all around. Pretty straightforward, so no need to really go into detail.
But when you begin to enter a corner, the car does what's called a "Dive" as weight is transferred forward onto the front tires. Grip is taken from the rear as weight is removed and given to the front. This is why the front tires do most of the braking and why you adjust brake bias; because those front tires have that much more grip and do that much more work. At the same time, the rear is prone to be loose as there is less grip at the rear. Turning at this point, with this kind of balance will likely result in a spin with the rear coming out from under you.
So you can see the front tires getting 30 grip, more than at a standstill / constant speed, but the rear tires get 15, which is much less than before. You might notice the overall grip doesn't equal 100 like it did before, but I'll explain that shortly.
So once you're letting off the brakes and transition into a turn, weight transfers again. For the sake of this walkthrough, it's a left turn. The weight is moved to the right side of the car, which is called "Roll" and the tires doing the most work are the outside tires. Inside tires (the left in this case) have decreased grip. In a lot of cases this is what makes hitting curbs on apexes safer; as there's little weight on the inside tire, it's not affecting the car that much to roll over it.
Again, here we see the tires doing the most work getting up to 30 grip, the right side tires; yet the left side tires are down to 15.
Last we're going to power out of the corner, with the accelerator down. The car "Squats" giving more grip to the rear tires, while taking away from the fronts. We get up go 30 grip in the rears but only 15 in the front.
So you're probably wondering why the other examples don't add up to 100. Basically put, the more weight you transfer, the more inefficient grip you have overall. What's that mean? It means smooth drivers will be faster and much more efficient. Sudden changes in weight, or giving a car too much roll in whichever direction, will mean that you'll be slower than a car that handles it better.
Using the grip numbers, if car A goes into a corner, throwing weight around, that weight will never settle and give the driver and even, safe balance. He/she might get 30 on the right side tires. But if car B goes in gentler, working up to that max weight shift; he/she might settle with more grip on the outside and more grip overall, perhaps 32 32 on the right side and 16 on the left.
The less weight that you as a driver transfer, the more overall grip you'll have. It's that simple.
Affecting Weight Transfer
There's a number of adjustments a driver can make to help with the balance of the car. Obviously the way a car is driven might possibly be the biggest way. Smoother means better. Don't also forget that various changes in driving affect it, too. Like I mentioned earlier, an understeering-on-throttle car can easily be fixed by letting off throttle to give the front (steering) tires more grip. But there's also numerous car setup options to help in a variety of situations.
ARBs
ARBs, or Anti-Roll Bars resist a car's roll. Above we talked about how a car has a tendency to roll from it's roll center on a turn. Well adjusting the ARB will either allow more roll (more weight transfer onto those outside tires) or less roll.
Generally when you're talking about ARBs, it's when the car has taken it's set in the corner, after turn in. The weight has settled and no more weight has been or will be transferred until you exit the corner. Stiffening the ARB will allow less roll and with less roll you'll have more overall grip. Yet a softer ARB will mean more grip once the set is taken but less overall grip. This might be advantageous in shorter, quicker corners, while a stiff ARB might be desirable for long sweeping corners.
These are adjusted usually by the front / rear, so you have to think about how it affects the two tires you are adjusting.
Low Speed Rebound/Compression Dampening
LS Dampening is coincidentally not related to how bumps or curbs are taken, but how weight is transferred to and from the particular shock. Every shock will have a rebound and compression rate, which obviously relates to how easily (or not) the shock will compress (MORE weight added to it) or rebound (weight REMOVED from the shock).
So if we were to make the LS Rbd softer in the front, the weight will transfer faster and more weight overall will transfer to them under braking. In this particular case, more weight would mean for better braking but might affect the car in other parts of the track, or could negatively impact the rear under braking. Or we could also make the LS Comp higher on a particular side, or all shocks, so weight transfers less because the compression is resisting the weight transfer more.
Downforce
Increasing downforce is an obvious way to increase weight and thus grip. So more of a rear wing angle will give you more grip at higher speeds. Keep this in mind also when setting up cars with differing aero packages.
Conclusion
So at the very least, take away the importance of smooth driving. Smoother means faster. Controlling weight transfer, using it to your advantage by identifying what tires need grip and adjusting will help you be much faster and more efficient.
Next Guide:
Advanced Suspension OR possibly telemetry introduction.
I'm taking a lot from a couple books in racecraft I've read, namely "Ultimate Speed Secrets: The Complete Guide to High-performance and Race Driving" from Ross Bentley as well as "Going Faster! Mastering the Art of Race Driving" by Carl Lopez and Danny Sullivan. Another excellent source is http://iracing.wikidot.com/ which acts as a great setup wiki for iRacing.
I'm also drawing some new knowledge from Drivers University, from Driver61.com.
Part 3: Balance & Weight Transfer
Finally getting around to writing this part 3. First I'm going to talk about what happens with balance and weight, and then follow up with various ways you can affect balance with car setup and driving style. The car setup portion will fit in nicely with part 1, where I gave very basic overviews of how the car's suspension works. It might also make a good segway into the next part.
First and foremost, a car's grip is determined by a great many things - tires, weight, the track, temperature, etc. However, this grip can vary depending on what the car is doing. Weight is the primary role in how much grip you'll have at any given time on track, whether you realize it or not. The more weight on a given tire, the more grip it has; and vice versa. That's why if you're understeering mid corner, you can let off the gas a bit to move weight forward so you get more front grip to turn. But don't go thinking you can just put more weight everywhere because it doesn't offset having to accelerate, decelerate and maneuver with all of it. So you have to work with what you've got.
All weight transfer occurs around the car's roll center and the terms associated with the specific weight transfer all describe what is going on. At rest, or at a constant speed (and direction), a car is evenly balanced.
For the purpose of this walkthrough, I will assign each tire a "grip number"... so the higher the grip number, the more grip.
You can see here, at rest / at constant speed, the car gets 25 grip all around. Pretty straightforward, so no need to really go into detail.
But when you begin to enter a corner, the car does what's called a "Dive" as weight is transferred forward onto the front tires. Grip is taken from the rear as weight is removed and given to the front. This is why the front tires do most of the braking and why you adjust brake bias; because those front tires have that much more grip and do that much more work. At the same time, the rear is prone to be loose as there is less grip at the rear. Turning at this point, with this kind of balance will likely result in a spin with the rear coming out from under you.
So you can see the front tires getting 30 grip, more than at a standstill / constant speed, but the rear tires get 15, which is much less than before. You might notice the overall grip doesn't equal 100 like it did before, but I'll explain that shortly.
So once you're letting off the brakes and transition into a turn, weight transfers again. For the sake of this walkthrough, it's a left turn. The weight is moved to the right side of the car, which is called "Roll" and the tires doing the most work are the outside tires. Inside tires (the left in this case) have decreased grip. In a lot of cases this is what makes hitting curbs on apexes safer; as there's little weight on the inside tire, it's not affecting the car that much to roll over it.
Again, here we see the tires doing the most work getting up to 30 grip, the right side tires; yet the left side tires are down to 15.
Last we're going to power out of the corner, with the accelerator down. The car "Squats" giving more grip to the rear tires, while taking away from the fronts. We get up go 30 grip in the rears but only 15 in the front.
So you're probably wondering why the other examples don't add up to 100. Basically put, the more weight you transfer, the more inefficient grip you have overall. What's that mean? It means smooth drivers will be faster and much more efficient. Sudden changes in weight, or giving a car too much roll in whichever direction, will mean that you'll be slower than a car that handles it better.
Using the grip numbers, if car A goes into a corner, throwing weight around, that weight will never settle and give the driver and even, safe balance. He/she might get 30 on the right side tires. But if car B goes in gentler, working up to that max weight shift; he/she might settle with more grip on the outside and more grip overall, perhaps 32 32 on the right side and 16 on the left.
The less weight that you as a driver transfer, the more overall grip you'll have. It's that simple.
Affecting Weight Transfer
There's a number of adjustments a driver can make to help with the balance of the car. Obviously the way a car is driven might possibly be the biggest way. Smoother means better. Don't also forget that various changes in driving affect it, too. Like I mentioned earlier, an understeering-on-throttle car can easily be fixed by letting off throttle to give the front (steering) tires more grip. But there's also numerous car setup options to help in a variety of situations.
ARBs
ARBs, or Anti-Roll Bars resist a car's roll. Above we talked about how a car has a tendency to roll from it's roll center on a turn. Well adjusting the ARB will either allow more roll (more weight transfer onto those outside tires) or less roll.
Generally when you're talking about ARBs, it's when the car has taken it's set in the corner, after turn in. The weight has settled and no more weight has been or will be transferred until you exit the corner. Stiffening the ARB will allow less roll and with less roll you'll have more overall grip. Yet a softer ARB will mean more grip once the set is taken but less overall grip. This might be advantageous in shorter, quicker corners, while a stiff ARB might be desirable for long sweeping corners.
These are adjusted usually by the front / rear, so you have to think about how it affects the two tires you are adjusting.
Low Speed Rebound/Compression Dampening
LS Dampening is coincidentally not related to how bumps or curbs are taken, but how weight is transferred to and from the particular shock. Every shock will have a rebound and compression rate, which obviously relates to how easily (or not) the shock will compress (MORE weight added to it) or rebound (weight REMOVED from the shock).
So if we were to make the LS Rbd softer in the front, the weight will transfer faster and more weight overall will transfer to them under braking. In this particular case, more weight would mean for better braking but might affect the car in other parts of the track, or could negatively impact the rear under braking. Or we could also make the LS Comp higher on a particular side, or all shocks, so weight transfers less because the compression is resisting the weight transfer more.
Downforce
Increasing downforce is an obvious way to increase weight and thus grip. So more of a rear wing angle will give you more grip at higher speeds. Keep this in mind also when setting up cars with differing aero packages.
Conclusion
So at the very least, take away the importance of smooth driving. Smoother means faster. Controlling weight transfer, using it to your advantage by identifying what tires need grip and adjusting will help you be much faster and more efficient.
Next Guide:
Advanced Suspension OR possibly telemetry introduction.
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