The Circuit de Catalunya requires a very well-balanced, finely-tuned setup. With a long pit straight and several tyre-pounding corners, the Spanish Grand Prix tests all parts of a cars makeup. It's one of the reasons why it hosts winter testing, and it's a great test of skill for drivers in F1 2018.
The first sector contains a long right hander that requires the perfect line to build speed without running wide. In sector two the uneven left-right of turn 7/8 is a menace that can spit you out into the wall, while the long 90 degree right of turn 9 has a gravel trap waiting for you if you take it too fast, but too slow and you are vulnerable down to turn 10. The third sector is a tight, winding, sector that can cost impatient drivers time and requires a responsive car before it spits you back out onto the pit straight for a long burn to turn 1.
Aerodynamics
As much as we want to take away drag for the big pit straight, we need a lot of downforce for the rest of the lap. As a result we have taken the wings down to 5-5, this gives us terrific levels of grip for turn 3, 9, and 16 which are all long, fast, right-handers.
You'll want to reduce the rear downforce, but it's best not to otherwise the rear becomes too light when accelerating through the corners and you risk flying off into the barriers.
Transmission
This part of the setup is about how the power is transferred into the rear wheels and onto the tarmac. A more locked on throttle differential gives a boost to outright traction, but it also increases tyre wear, which is something this track is notorious for. As a result we have added just 1 percent on throttle differential lock for a small addition to traction while not killing our tyres.
Off throttle we want to unlock the differential a bit more to allow for better entry into corners, and while it decreases stability in the mid-corner the rest of the setup allows us to handle that.
Suspension Geometry
This part is all about how the tyres are mounted to the body of the car. Camber is about the vertical alignment with the car. F1 cars have negative camber to provide more grip in the corners, and around Spain we want to add a little more camber so we can accelerate through those long corners and stick to the surface more. It does add a bit of tyre wear and hurts us on the straight, which is why we have only set them to -3.10 and -1.60, but you have to have more mechanical grip on this circuit.
Toe is the horizontal alignment of the wheels. The front tyres have toe out which sets the front edge of the tyre away from the body of the car and the rear edge into the body. This helps with responsiveness on turn in, and we are adding some toe out here so that we can really get the nose of the car into the corners. Adding toe out reduces straight line speed, so we have to add toe in to the rear tyres to counter this. Adding all this camber and toe does increase tyre wear, but it's needed to get around the circuit in good time.
Suspension
How you tune your geometry and your suspension will have the biggest effect on handling. Here we are setting the stiffness of the springs and how much we allow the weight of the car to move as we brake, accelerate, and turn.
We are stiffening the front suspension a little to improve responsiveness again and prevent frontward weight transfer under braking. We have left the rear suspension alone, making it softer than the front. This improves rear stability relative to the front, and allows weight to shift back under acceleration, aiding in traction.
We haven't touched the anti-roll bars because stiffening them will increase responsiveness but also increase tyre wear, something we have already pushed with our geometry, and softening them will only reduce responsiveness and mean we struggle to change direction. With three quick changes of direction we can't stand any increase in body roll as that will make the car less responsive in a chicane.
Our ride height is lowered as much as possible so we can gain straight line speed. There are a few bumps on this circuit though, as well as some elevation changes, and we also need to ride the kerbs frequently to find the appropriate racing lines so a 4-4 ride height is as low as we dare go.
Brakes
We need good levels of stopping power for Spain. The heavy braking zone of turn 10 is a great overtaking place, as is the braking zone of turn 1, and in order to defend or attack there we need good stopping power. However, with the high tyre wear comes a bigger chance to have a lockup, which will cost time and ruin a race strategy. As a result we can't pump the brake pressure all the way up. Somewhere in the range of 83-87 percent is good, but it depends on your own style somewhat.
The brake bias is all about which wheels, front or back, do the bulk of the braking. A normal brake bias is 60 percent front, here we have moved it back slightly to 58 percent, this increases oversteer a shade, while also making the car a little less stable under braking. That's good as it compensates for some of the mechanical grip we will lose during the race.
Tyres
We have left the front tyre pressure alone, because while increasing it would improve responsiveness, it would also increase tyre temperatures and wear, which is already marginal. Reducing it would negatively impact responsiveness so we have left it at 23.0 psi.
We have taken away some pressure from the rear tyres though so that we can get a little more traction and help power out of the corners, especially important for coming out of the painfully slow turn 14/15 chicane and then accelerating all the way down to turn 1.
Weight Distribution
By moving the ballast rearwards ever so slightly we have improved traction once again and also added a touch of oversteer to help get the car into corners. This is a nice way to round out a setup that balances out straight line speed and cornering grip and responsiveness.
The Spanish Grand Prix is a test for man and machine, and it can be highly frustrating with a poorly balanced setup. This is a good starting point to tune in line with your own driving style. See you on the time sheets!
Spanish Grand Prix Wet Setup
Front Wing: 8
Rear Wing: 7
On Throttle Differential: 55%
Off Throttle Differential: 70%
Front Camber: -3.10
Rear Camber: -1.60
Front Toe: 0.09
Rear Toe: 0.29
Front Suspension: 7
Rear Suspension: 3
Front Anti-Roll Bar: 7
Rear Anti-Roll Bar: 4
Front Ride Height: 5
Rear Ride Height: 5
Brake Pressure: 85%
Front Brake Bias: 57%
Front Tyre Pressure: 23.0 psi
Rear Tyre Pressure: 21.1 psi
Ballast: 7