DiRT Rally Tuning Comprehensive Guide

DiRT Rally Tuning Comprehensive Guide by Bilas

A common complaint I’ve heard about DiRT Rally is that cars don’t have a lot of front-end grip out of the box. Some early reviewers hold this against DiRT Rally as a sim, and rightfully so: most rally cars in real life will be built to have an overabundance of front end grip and a lot less rear grip. However, within the bounds of this sim, it’s possible to get much more slidey cars. I’ll describe how in this tuning guide.

First, let’s define some basic terminology that I’ll be applying to this Tune Guide. The two most important terms I’ll be using are OVERSTEER: when your rear tires have broken loose and your front tires are maintaining their grip. and UNDERSTEER: when your front tires have broken loose and your rear tires are maintaining their grip. OVERSTEER IN ACTION and UNDERSTEER IN ACTION. Also, TURN-IN: how responsive your car is when going from straight to turning the wheel, where more turn-in means more responsiveness, less turn-in means more sluggishness. If any more technical terminology comes up, I’ll try to define it.

WHAT DOES EACH OPTION ACTUALLY DO?

Before I start this guide, I have to disclose that despite playing a lot of Colin McRae Rally 2005, Forza 1-4 and now DiRT Rally, I do NOT have perfect knowledge of tuning or setting up the fastest tune. Furthermore, I might be flat wrong on some of these. Perhaps more importantly, if I give recommendations, know that a lot of car-feel preferences are highly subjective, and dependant on what the driver himself wants to get out of his car.

IMPORTANT! Every Car you can own has an unlock called “Advanced Tuning.” Once this option is unlocked, you can drill into each tuning option to get access to different sub-options by pushing [Enter], (A), or whatever the equivalent is on your setup.

Brakes

  • Brake Bias: Defines which axes (front or back) braking strength is applied to the most. Typically on tarmac environments, this ratio needs to be towards the front (70:30 or 60:40 is generally recommended). A front brake bias will make the front wheels lock before the rears do, which generally results in braking understeer, which is a lot safer. A balanced or rear brake bias will result in the rears locking, which could help with turn-in, but generally, it’s preferred to have more front-bias and use your handbrake when you want to lock the rear tires and induce oversteer.
  • Brake Strength: Changes the braking force applied to your wheels. Keep in mind that your car can only brake as hard as you have traction on all of your wheels; if your braking force exceeds available traction, your wheels lock. When your wheels are locked (due to the properties of static and dynamic friction) your car will continue to slow, but at a lesser rate. Thus, you should increase your brake strength until you lock your wheels too often. On tarmac surfaces, your tires have more available traction, so you can increase your brake force to take advantage of a grippier surface. Newer players who have a tendency to mash the brakes down fully should lower brake strength. Experienced racers who can read surfaces and tell how much grip will be available should increase brake strength and use their discretion to brake at the optimal amount.

Differential (Front+Rear)
(Note, depending on your car’s drive {FWD, RWD, 4WD}, you may be missing some of these options)

  • Limited Slip Differential (LSD) Driving Lock: A limited slip diff allows two wheels on the same axis to spin at different speeds. Lowering the driving lock percentage grants more grip under acceleration. LSD’s often come into play when accelerating and steering at the same time. Without getting too much into how LSD’s function, the important part of tuning DiRT’s LSD is the balance between front and rear driving lock. If you notice your car understeering out of corners, lower the front driving lock percentage and raise the rear driving lock. In this case, it’s perfectly acceptable to go to extremes: on 4WD cars, lowering the front LSD driving lock to <30% and raising the rear LSD driving lock to >70% can help give you much less understeer and help you come out of slow speed corners much smoother.
  • LSD Braking Lock: Like Driving lock, but during deceleration instead of acceleration. I admittedly know less about tuning for braking lock, but I tend to keep the value close to the equivalent value for acceleration. If you notice an abundance of braking understeer, raise the front LSD braking lock percentage or lower the rear braking lock percentage, and visa versa.
  • LSD Preload: Applies torque when you aren’t really doing anything to your drivetrain… I think. Again, I’m pretty hazy on this setting, but generally leave it unchanged. It could be extremely important, however: further testing required.

Viscous Differential

  • Viscous Differential: Strengthening the V.Diff will restrict wheel speed difference between the front and the rear axes. This, in turn, will slow down the rear wheels and speed up the front wheels in driving oversteer situations when your rear wheels have broken free, your front wheels are still gripping, and throttle is applied. When your rear driving diff is stronger than your front driving diff, this reduces oversteer and increases understeer when sliding. Typically, I keep the V.Diff settings similar to the front LSD driving lock settings (fairly loose), as this allows me to use the throttle to break my rear wheels loose and induce oversteer.
  • Torque Bias — Front/Rear: Determines how torque (twisting force) is split between the axes. Typically, more torque is put at the rear, because during acceleration, weight is shifted to the back of the car. Conservative setups shift 60% of the torque to the rear. Personally, I like putting at least 70% torque in the rear, as having only 30% of torque at the front will allow my front wheels to maintain grip in difficult situations under acceleration, thus decreasing understeer.

Gears

First, have a look at a typical power curve of a naturally aspirated, non-limited car in real life. Keep that in mind when I talk about power curves, and note that at redline RPM, horsepower begins to drop off, and peak horse power, a statistic shown in game in the garage, comes some time before redline.

  • Final Drive Ratio: Changes how quickly you can run through all of the gears under flat out acceleration. Another way of thinking about gear ratios is thus: shorter gear ratios mean that in the same gear at the same RPM, your car goes slower, but it reaches that speed faster. Thus: shorter gears = better acceleration at the cost of (potentially) top speed and having to shift earlier and more often. A general rule of thumb is that you should adjust your car to hit redline in top gear at the absolute fastest part of the rally circuit, though that rule is also flexible.
  • 1st-top gear Ratio: In Advanced Tuning, you can adjust each gear ratio individually. This allows you to change the sometimes atrocious default gearing that come with some of the older cars specifically. It’s my personal preference to have a longer 1st gear, which helps me pull through hairpins, and shorter gaps between 2-6th (if applicable). If you have a high powered Group B car, try a longer 6th gear if you find yourself ever hitting redline.

Before we leave, look at the example above of the power curve. When should you shift if you are driving a car that has that power curve? If you have a short gear ratio, you’d want to keep on applying throttle until you hit around 6000 RPM. When you shift up a gear, your engine will be driving somewhere around 5000 RPM. This will allow you to maintain best average horsepower. If you have a longer gear ratio, you might want to hold off on shifting until 6200 RPM, as when you go into the next gear up, your RPM will be around 4800 RPM due to more spacing between gear ratios. Remember, the goal is to average the best power, not necessarily drive to either the power peak or the redline before every upshift.

Suspension

  • Ride Height: Determines ground clearance, which also determines how much spring travel is allowed before BOTTOMING OUT (when the spring compresses to the point that the top of the wheel hits the wheel well, which is really bad). When your car rides high, that raises the center of gravity of your car, which is BAD! So what should you do? For gravel stages (currently Wales and Greece), most cars should ride at least at +0.3in. With this extra ride height, you can afford to soften the spring rate which will reduce the amount of time your vehicle’s tires are off the ground during bumps and jumps, which increases the amount of time your vehicle has traction to turn, accelerate, or brake. We’ll get to that later. For tarmac stages, I like stiffening my springs significantly and lowering my ride height to -0.1 in or -0.2 in. This improves both front and rear grip due to lowering BODY ROLL: when a car leans away from the direction it’s turning. In most cases, the ride height of the front and the rear should be exactly the same.
  • Spring Rate: How stiff your ride is. Balancing front and rear spring rate is one of the easiest ways to balance understeer versus oversteer, but exercise caution: soft front springs and stiff rear springs will mean your car eats bumps in the front but bounces hard off of them in the rear, which will lead to your car bucking forward like a bronco and face planting. Also, something to consider is where the weight is in the car; if you are driving the Lancia Stratos, the majority of the weight will be in the rear, which means that your springs in the rear should be stiffer than your average set up to prevent the rear wheels from bottoming out. On tarmac surfaces, stiffen your spring rate as your car won’t have to eat bumps to have competitive pace (at least half way to firm), and on gravel, loosen your spring rate.
  • Anti-Roll Bar (ARB): A link between your left and right suspension which helps improve body roll (as discussed above). In practice, a stiffer setting for the anti-roll bar will decreaseSOLID-STATE CORNERING GRIP: grip during sustained turning, such as “3 long” on the callouts. While having a good amount of turn-in oversteer is often desireable, solid-state cornering oversteer/understeer balance should be closer to neutral: if you start sliding, you don’t want to understeer right away, and you certainly don’t want to oversteer out of control and spin your car around. Thus, depending on all of your other setup, you have to adjust your Front/Rear ARBs independently until you find a setting that works for you. Typically, I like having average stiffer ARBs on the tarmac and just a bit softer ARBs on the gravel, but in terms of balance of stiffness between the front and the rear, it’s highly dependent on your car. If you find that you can’t get front end grip going through long 2’s, 3’s and 4’s, soften your front ARB and stiffen your rear ARB.
  • Camber Angle: No doubt some of you have seen idiots do really dumb things with camber.This is -23.6o of camber. Despite being a really shit setup, it’s a good illustration of what camber is: the angle created by swinging the bottom (contact) portion of the tire outwards from the car and the top of the tire inwards toward the car. Negative camber will help cornering grip. I wouldn’t extend beyond -1.5o of camber, but having a higher negative front camber (especially on tarmac) will help with front grip during cornering, similarly to what softening the ARB does. If your negative camber is too high, braking and acceleration traction suffer. For the rear tires, I hesitate to go beyond -1o because further increasing the camber on the rear tires will hurt straight line acceleration.
  • Toe Angle: Anyone here pigeon toe’d? That’s called toe-in when applied to racing. Front positive toe angle (toe-in) will point the front tires towards each other, and this increases turn-in responsiveness. This is highly important for rally racing, as this specific setting will help cars in DiRT Rally drive more like the rally sims of the past (RBR and older CMR titles). I’d say don’t exceed +0.3o front toe angle. Rear toe angle is different… typically you want negative toe angle on your rear tires. Negative angle on the rear tires will allow for extra oversteer during turning and acceleration. This sounds bad, but is actually good for rally racing! If you are in tight turns and experiencing understeer, jam on the throttle to break your rear tires and swing your back around. Rear negative toe can start at -0.5o, but I wouldn’t go too much beyond that value, as this could impact straight line speed and stability.

Damping

  • Bump: Bump stiffness is how easy your springs are to compress. Softer bump will let you glide over rough surfaces, but you might find your car driving like a 1976 station wagon. Over rough surfaces (Greece and Wales) you need a slightly softer bump so your car won’t get airborne over small bumps and maintain good traction. Having stiffer rear bump and softer front bump will aid in turn-in, which is GOOD! Don’t take bump to the extremes, I usually like 4/10 soft in the front and 5-6/10 in the rear, but that should change based on the car.
  • Fast Bump: At a certain point, when you land from that jump or you graze the raised edge of the gravel, your spring will compress really fast. If it crosses a certain threshold, the spring rate for fast bump kicks in. Having a softer fast bump will allow you to travel much more smoothly through jumps or in really uneven surfaces (think of the narrower sections of Greece), but make sure that you have enough spring travel to have a softer fast bump and not bottom out. This may require raising the car’s ride height in the suspension settings. I haven’t experimented with having a stiffer fast bump, but it doesn’t seem like a great idea to me unless you want to maintain a lower ride height and a softer spring rate. I typically set my fast bump to the same stiffness on tarmac, and 1 or 2 steps softer on gravel.
  • Fast Bump Threshold: The compression rate (measures in feet per second) which bump stiffness is switched to fast bump stiffness. I usually leave this where it is.
  • Rebound: Like bump, but instead of compression, rebound determines how fast the springs decompress. I like having rebound firmness 1 unit higher than bump, but I haven’t played too much with rebound setting.
  • Fast Rebound: Like fast bump, but mostly applies when getting airborne, when tires rapidly go from loaded to unloaded. I usually keep this about the same as rebound, but again, I’ll play with it more.
  • Fast Rebound Threshold: Should be explanatory at this point.

TROUBLESHOOTING

  • My car is unresponsive when turning the wheel!: More negative front camber (don’t exceed -1.5o ), more positive front Toe Angle (don’t exceed +0.5o ), softer front damping, or stiffer rear damping
  • My RWD car oversteers at the slightest bump or around turns during acceleration!: Lower the rear differential driving lock percentage, weaken rear ARB and strengthen front ARB, increase negative rear camber angle (don’t exceed -1.0o ), lower rear Toe Angle (try +0.2o or +0.1o ), try stiffening front bump and rebound, and softening rear bump and rebound (don’t go to extremes).
  • My car tends to slide excessively after the turn has finished!: Weaken the rear ARB/Strengthen the front ARB, lower the rear Differential Braking lock.
  • My car gets bogged down in hairpins!: Lower the 1st gear ratio, strengthen the rear driving lock (don’t be afraid to put it way up!), shift up to 80% of the torque to the rear (70% recommended, perhaps 80% on AWD, mid-engine cars like the Peugot 205), strengthen the center viscous differential, increase the rear toe angle to around +0.6o , but no further.
  • My car tends to slide into hard braking turns!: Shift brake bias to the front (around 70-75%), stiffen rear rebound rate, stiffen front bump rate.
  • The ride is too rough through bumpy sections!: Raise your ride height in the front and back, soften your spring rate in the front and back, soften your fast bump/rebound damping rates, lower your fast thresholds.
  • My car is unresponsive on tarmac!: Lower your ride height and at the same time, stiffen your spring rate, stiffen your bump and rebound rates, increase negative front camber, increase positive front toe angle.

4 Responses

  1. just says:

    thank you i took notes… really trying to get better at this game but its confusing.
    this should help so much.

  2. Mamo says:

    Thank you for this article, very helpfull”

  3. Mamo says:

    Thanks for this extensive and helpfull article!

  4. Shoop says:

    This is awesome! The trouble shooting section is especially helpful.

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