DIRT 5 4.03 Update: The deadzones have finally been fixed!
A new section has been added to this guide to explain in detail what the in-game advanced settings for controller input now do.
A big part of this guide is now irrelevant, or less relevant, but I'll keep it around just in case you feel like the in-game settings just aren't enough or if you still want to know how Steam Controller works.
If an update ever comes with a change that affects this, I will update the guide accordingly.

Unfortunately this won't make the steering faster, or slower, this is only to help you fine tune your input for you to feel more in control of the car.

As for the Steam Controller Support, it goes beyond just the Steam Controller itself, it actually supports basically any controller that Windows, and maybe even Mac or Linux, recognizes as a game controller.

This guide will only scrape the surface of what this tool can do, but it will show you how to bypass the lack of options in some games, in terms of setting up your gamepad's analog sticks' sensitivity and deadzones.

Steering Linearity - This will change your input's curve sensitivity.
More to the left = Less sensitive at lower amounts of input (Example: 25% of stick input = 10% seen in game)
More to the right = More sensitive at lower amounts of input (Example: 25% of stick input = 35% seen in game)
If you feel like your cars turns too much when you slightly move the stick, set the linearity lower (left), if you feel like your cars turn too little when you slightly move the stick, set the linearity higher (right)
This will not affect Steering Saturation (explained later). 100% input will always be 100% steering.

Steering Deadzone - This should be used to remove stick drift.
The higher this is set, the more the stick will have to be moved for the car to start reacting to your input.
If you see that the car is turning by itself, set this higher until the car turns only when you want it to.

Steering Saturation - This is how much you need to move the stick to reach maximum turning.
Having it set to the highest value means it will be a 1:1 ratio to your input. The car will only reach maximum turning if you turn your stick all the way.
If you want your car to reach maximum turning before you push the stick all the way (or your controller is broken and the stick can't register max input), start reducing the amount of saturation.

All of these adjustments can be tested out of the track by going into the "INPUT REPORTING" menu on the previous page.

This section is no longer necessary. The in-game settings now allow you to do this with enough depth.
Only use this if you feel like the in-game settings aren't precise enough or as a reference for other games.

If you are familiar with how Steam Controller Support works, first, why are you here, second, skip this step if you just want the settings for this game.

To enable Steam's Controller Support feature, enable the Big Picture mode:

We will only need Big Picture to enable this, if you don't like it you can just exit the mode once we're done with activating the feature we want.

Once we're in, head to the Settings menu:


And finally go to Controller Settings:


From here, you want to enable the configuration support for your gamepad. Steam will tell you which type of gamepad you have connected:


Once you're done and want to leave Big Picture, just go all the way back to the home page by lightly spamming your ESC key, press the power button and Exit Big Picture:

This section is no longer necessary. The in-game settings now allow you to do this with enough depth.
Only use this if you feel like the in-game settings aren't precise enough or as a reference for other games.

As I mentioned in the description, DiRT 5 cuts your total input range by about 50%
Although 50% off is typically seen as a nice deal I can't say the same about this unwelcome input range cut.

This can cause issues like not knowing when the car is going to start turning, how much it will turn and when it reaches maximum turning.

DiRT 5 loses about 25% on both inner and outer deadzone. This basically means you need to push your stick quite a bit off the center to start turning, but you also reach maximum input well before your stick hits the edge of the socket.
Just imagine you're driving down the road with your car, never knowing how much you need to rotate the steering wheel for the car to start turning, sounds safe right?

Let's begin by making sure the controller is connected and enabled, then you should see this:Simply click that button to proceed.

Moments later this should open. Let's head to the left stick configuration because that's where steering is typically done:


Once you're in, you'll find some basic configuration stuff, but for what we want to do we need to go to additional settings:

You can basically just copy the Horizontal Scaling and Anti-deadzone values since these are simply to patch the game's excessive deadzone:
If you find that you have some stick drift, run the game, keep this window open and slowly increase "Deadzone Inner" until the drift is gone but don't change the anti-deadzone.

The best way to tune deadzone is going in the cockpit view in a well lit area where you can clearly see the car's steering wheel moving as you move your analog stick.
Ideally you'd want the car to start turning when you think you have moved the stick just enough for a small input to be read by the game, but once you release the stick it should always recenter the wheel.

For me the steering was still a little too sensitive so I adjusted the response curve so I can do finer adjustments easier. (Less sensitive inputs near the center for an ease-in effect)


If you're curious, this is what each setting does:

• Horizontal scaling will set the maximum input the game will receive by multiplying your total input range by the value you've set, effectively getting rid of outer deadzone. DiRT 5 will reach maximum steering at 81% input, by setting the scale to that 81% reaching full input in your controller will match the steering maxing out.
  
• Anti-deadzone works as the name says, it removes the game's deadzone and it does it by raising the minimum input your controller will send to the game. After some tinkering DiRT 5 seems to only respond to inputs over 25% (which would be 0.250).
  
• IMPORTANT: Horizontal scaling is the last filter to be applied which means we've lost 19% of our total input range, so we need to make sure we still get 25% anti-deadzone, not 81% of 25% anti-deadzone (which would be 20%).
  To get 25% anti-deadzone after it gets cut by 19%, just divide 25% by 81% and we get our 0.309 anti-deadzone value.

Before you close everything, I'd recommend going back to the controller overview and getting rid of the default deadzones Steam adds to the other analog inputs like the triggers and the other analog stick:

For the triggers:

For the stick:

This can be applied to any game with a lacking controller implementation that doesn't allow you to fine tune deadzones and sensitivity curves.
It's a shame we have to resort to this because games no longer give us the options, but luckily Steam has our backs.

I'll be sure to keep the guide updated in case a patch changes the controls' behavior.

Enjoy your hooning time in DiRT 5 😁