iRacing Truck Setup Guide

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The default iRacing oval setups tend to be reasonable with a little too much push (understeer) for my taste, especially the fixed setups. This is so that most drivers can get in and get around the track without wrecking at every turn and causing a wreckfest.

Over the last few seasons there have been some great setups posted in the forums, some can be a little on the sketchy side. I like to have a comfortable truck that will stay under me for the long run.

This guide is an attempt to outline how to adjust the car and what makes a fast setup. This is a community effort and I’ll post updates as folks chime in.

I still use the Busta Wrench Setup Tweak Guide a bunch, especially for the oval cars.

While there are some truck adjustment items below I wanted to focus this post on how I go about doing setups week to week and what I try to do to get a Truck that is fun do drive.

I generally start with the fixed setup at a track, if i haven’t been there since the last build, generally iRacing is good at updating things like tire pressures as the tire model changes and older setups may not reflect that season to season. IF i jump in and just don’t like the feel I’ll a/b the setup with last seasons to see if that will give me a leg up on having something drivable.

As a race driver I make a pretty good Crew Chief, so I focus on finishes rather than outright speed.

The key for me is balance, this refers to understeer (or push) vs oversteer (loose) from lap to lap over a fuel run.

Loose is fast but too loose is just a nightmare to run, as is too tight. If you have a Truck that is pretty neutral, gets in the corner and you can control it with the gas pedal, you’re in the ball park to control your own balance.

So i get in the garage load up the fixed setup and immediately drop the front ARB a few clicks, it’s the easiest way to get the front end working a little better.

Go turn a few laps and get a feel for things.

A lot of the setups for the Truck are coil bound and there isn’t a lot you can do with the front end for spings and shocks. (ie you can’t get a little more front bite by lower the front bump setting as it’s usually at 0 already)

With the setup being reasonably close, I focus on getting the feel of the Truck right, which means Tires Tires Tires. (or Tyres Tyres Tyres if you’re an Aussie, or Tars Tars Tars if you’re southern …. I’m both )

There’s a lot you can get done without leaving the tire page. Run 10 – 12 laps and check out the wear and temps. If you car is going one way or the other … loose or tight and you can see that the tire on that corner is hot in the middle and wearing out faster then it’s got too much air in it. Drop it down a couple clicks and go again.

If  I get to the point where the tire wear is pretty good but it’s still not doing what I want I’ll refer to the Setup Tweak Guide

Remember to work on the end of the car you want to change, where you can.

So … rules of thumb.

1. Lower the front ARB a smidge

2. Get it close with Track bar

3. Fine tune and handling with Tires.

Let me know how it goes for you.

Cheers.

Shane

 

Truck adjustments.

Front Springs

Normal range for the front springs are 350 -450 lbs, in 25 lb increments

As well as helping to set the ride height and rake, springs help with mitigating body roll along with the shocks and ARBs. Stiffer springs make for more responsive handling with softer springs helping with grip.

Shocks

A lot of fine tuning is done with the bump and rebound of the shocks on the circuit and teams spend a lot of time with it.

I have some base bump and rebound settings that feel pretty good. I’ll work on the track, turning laps and looking for things that can be helped.

With a coil bind setup the front is essentially slammed on the bump stops with a combination of low spring weights, soft bump settings and very stiff rebound. The idea is to keep the front end down and not let it move much. I try to find a balance where I can have some adjust-ability in the truck, but with coil binding that’s pretty much limited to the rear.

Anti Roll Bars

The front Anti Roll Bar ties the front wheels together and controls how the wheels work together through the turns.

A stiffer front ARB will help when changing direction and initial turn in. Too stiff and the front end can’t work and you’ll have push. Too soft and the front falls over some causing the rear to twist and get loose.

Camber

The latest thinking is to run more camber on the front left than required to get even temps. This helps drag the car into the corner and helps with general handing. I try to keep right front temps within 10 degrees across the tire with the inside being a little hotter than the outside.

Caster

Caster effects the twisting of the chassis as the wheel is turned. Caster rotates the front geometry as the wheel is turned. More caster helps with turning the car at the expense of rear grip.

Toe In/ Out

Toe In   – helps with straight line stability
Toe out – helps with initial turn in

While a little is good, more is not always better. Excessive toe in/ out will greatly affect tire wear.

The majority of the setups I’ve seen have been running a +4 -4 Rear steer setup.

We’ve been running this setting as a default for several seasons now. Here’s a tip to try out. If your truck is turning really well, maybe even a little loose and you’re trying to dial that out. Take out some rear steer, it will tighten the truck up and as you aren’t scrubbing the tires so much, help with straight line speeds and tire wear. It may just give you an edge as you go to pass down the back stretch.

Camber

Rear cambers help the car turn in conjunction with the amount of rear steer dialed into the setup. I aim for a little higher temps on the inside of the track, so outside of left rear and inside of right rear. If the temp spread is higher than 10 I’ll stand the tire up to try and even out the temps.

Tire pressures

Tire acts a spring, with softer tires generally offering increased grip. With the updated tire model (NTM) it’s more about tire wear than even temperatures as it was with the old tire model.

Although it’s quite ok to have uneven tire temps, as long as the tire wear is more even having an inner or outer temperature significantly different to the other two temperatures could mean that the tire isn’t being used to it’s fullest.

Tire pressure increases with temperature, which also affects tire grip. One to the things I try to achieve is good balance over a fuel run. After running several laps (preferably at least 10) take a look in the garage at the hot tire pressures, a front pressure significantly higher then the rear could mean you are using that end of the car up faster and will likely lead to understeer. The opposite of course holds true for the rear.

Brake Bias

Locking up the rears usually leads to a quick swapping of ends and the air being filled with expletives. While a rearward bias will help you turn the car getting into the corner, too much will lead to bad things.

While on short ovals such as Martinsville you can use brake to help rotate the car, a rearward brake bias will make life difficult when coming into the pits.

I tend to move the brake bias rearward a few clicks from the default, depending on the track, so that i’m not locking up the front tires under heavy braking. The truck has a good amount of grip compared to the cup and nationwide cars so I don’t tend to brake as heavily in it. You need to have confidence in what the truck will do under heavy braking, in case you need to avoid something on the track.

Driving Style

My goal with a setup is to manage the balance of the truck. If you burn up the front driving too hard into the corner the Truck will tend to push more through the run. The same holds true for sliding the rear, you’ll end up fighting a loose truck that will try and put you in the wall every corner.

You can make a lot of time and consistancy by backing up the corners and being smooth.

Of course there are times when you’ll want to be able to mash the gas and keep it wide open for a few laps and knowing how your truck will handle that over a few laps will definitely help you out.

 


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