Tag: tutorial

4.2: Surviving the first corner

Posted on by Jaap Grolleman

“You can’t win a race in the first corner, but you can lose it in the first corner” is one of the oldest racing adages (another being ‘To finish First, you first have to finish’). And it’s one of the most valuable (and least adhered) lessons, as merely surviving the first lap can ensure a points finish, especially in the lower splits of road racing. But does first-corner-survival come down to mere luck, or is there some skill or strategy involved? We catch up with some of the VRS coaches.

Martti Pietilä:
“The most important thing about starting a race (and the first corner) is also one of the most fundamental concepts of racing overall: look where you want to go. When driving alone, this is quite natural, and most of the time we just need to think about how far we look, at either the apex or the exit. However, at a start there’s so much going on around us, we tend to forget this very basic requirement, and start to look at the cars around us. Especially if there’s a crash in front of us, we get so fixated on that and continue to plow in to the mess, even though there was plenty of time to avoid. The key here is to be aware of whats happening around you, not just looking at the cars around.

Lastly, if possible, I try to stay away from the middle of the track, so that an ‘escape’ plan is available if things go wrong!”

Jeremy Bouteloup:
“The best way is to think of all possible scenarios during the approach of the first turn, different racing lines and how you’ll have to position the car. This will help anticipating what will happen and will allow you to react in due time. A second thing is; don’t do anything unpredictable because that will increase the chances to be hit. Other than that, there’s no magic for this and with experience, you’ll learn when and how to react, and it’ll come naturally.”

Olli Pahkala:
“Keep up situational awareness, stay sharp and smart and try to avoid any sudden movements in a steady flow of cars.”

Martin Krönke:
“Heh, the easiest thing is just to qualify on pole. Less issues then! But still you can’t really prevent people running into the back of you. Perhaps if you notice in time that someone is going to overshoot the corner, you may prevent contact by not turning in. But if someone is messing up real bad, chances are you can’t do much at all. So really, if you’re in the pack, just expect the worst and be ready to react. Be prepared to brake and not run into the carnage. If the worst case doesn’t happen, good. If it happens, at least be prepared for it.”

David Williams:
“Regardless of where you start, your initial focus should always be on having a clean, disciplined launch. If you’re on the front row, try not to be distracted by drivers behind you. Be prepared to defend into turn 1 if necessary, and try and visualise the line you wish to carry through the corner before you get there. However, if you find yourself starting in the middle of the pack, it’s important to realise that you must give yourself the opportunity to react to, or take advantage of situations which will change and develop quickly. Be willing to brake much earlier than normal if closely following another car, as it’s likely they’ll be reacting to cars ahead and the pack will be backed up. Avoid erratic or aggressive inputs which may catch other drivers unaware, potentially causing a collision with you. At the same time however, be ready and aware of opportunities which may present themselves to you, and remember how much later you can brake if you choose a line with no cars immediately ahead.

One more thing, I consciously balance risk versus reward on tracks where it’s hard to overtake, or for sprint races compared to endurance races. But it’s also important to be aware that the rest of the grid are more likely to take extra risks as well, and to make allowance for mistakes from others to be made and ultimately capitalise on.”

5.7: Differential basics

Posted on by Martin Krönke

The differential (or diff, for short) allows the left and right wheels to rotate independently, which helps balance the car through corners. Its configuration determines how much of the torque coming off the engine is transferred to each wheel. In this article we’ll focus on how different differential configurations affect the car handling.

If you’re interested in the mechanical workings of a differential, we recommend you check out the following videos: ‘How a Differential Works?’, ‘Understanding Limited Slip Differential’, and ‘Working of Limited Slip Differential’.

Locked differential (also known as a spool)
The spool is essentially a solid axle connection between the left and right wheels, or a fixed differential. Some people weld their differential fixed, for instance to allow easier drifting. A spool ensures both left and right tires rotate at exactly the same speed.

A spool gives you good traction accelerating on a straight line, but the handling of the car is compromised during turning. When going around a corner, the outside tire has to travel a longer distance. So, the inside is forced to rotate faster than it needs for the turn radius and hence spins. This causes stress (wear) on both tires and the drive train. In terms of handling, this causes understeer when decelerating, and oversteer when accelerating.

Spools are typically used in karts, drag racecars, some oval race cars and some road race cars. Notable road car examples on iRacing are the V8 Supercars.

Open differential
A completely open differential allows the left and right tires to rotate entirely independently. This helps with turning. The open diff also allows more torque to be transferred towards the less loaded tire. This is quite unfavorable when one tire is on a slippery surface like mud, grass, ice or wet track markings, as the tire on the slippery surface will end up spinning, consuming most of the available engine torque. Consequently, there may not be enough torque going to the tire on the grippy surface, so acceleration would suffer.
In terms of handling, an open diff gives you oversteer at the entry of a corner, and will understeer at the exit. Most open diff cars are underpowered, however, high-powered open diff cars (or cars with open limited slip differential), may spin the inside wheel on corner exit. Excessive spin on the drive axle cause that axle to lose grip causing sudden oversteer (on RWD cars) or understeer (on FWD cars).

The open diff presents challenges in low traction conditions. In addition, the balance changes suddenly through the corner, which is not desirable for a race car, as you are giving up traction. On iRacing, the Pro Mazda, Skip Barber and Spec Racer Ford are open diff cars.

Locking differential
A locking differential can behave both as an open differential and as a spool. The locker mechanism unlocks the wheels during corner entry and mid-corner and locks them on corner exit, when on the power. A popular locking differential is the Detroit Locker, used in NASCAR.

Limited slip differential
As we saw, both a spool and an open diff have their issues, especially in racing conditions. Most race cars thus use a limited slip differential, which offers the best of both worlds. You can tune the differential to behave as an open differential in certain conditions. And you can tune it to apply a certain amount of “lock” between the left and right tires. By optimizing the diff setup, you can improve your car handling through a corner.

Adjusting a limited slip differential
A limited slip differential might have any (or none) of the following adjustments available, but here’s what they do:

  • Number and/or type of of friction & clutch plates: the more friction and clutch plates, the more locking happens through all corner phases.
  • Preload spring: defines the base amount of force that is applied on these friction and clutch plates. With small enough (or negative) preload, you can open up your differential. The heavier the preload spring, the easier your differential will lock.
  • The Ramp angle: this can be used to tune the amount of locking under deceleration/acceleration. For instance 50/80, where 50 stands for the locking during deceleration into corners, and 80 for acceleration out of corners.

Each car in iRacing has a different differential settings available, under different names and configuration values. For example, here are the differential settings for the McLaren MP-30:

Up to you

You can achieve identical handling with completely different diff builds/configurations. As always, it’s important to experiment with each setting to gain experience with the car and to develop an instinct for how to approach differential setup. However, here’s a starting point when you think about each diff setting:

  • You want to start with changing the number of plates to control how quickly the differential builds up locking force. The more locking force, the more it behaves like a locked diff and vice versa, the less locking force, the more it behaves like an open diff.
  • You may consider the preload as a form of general trigger for sensitivity. It set a minimum amount of locking force that is applied at all times.
  • You’d consider changing the ramp when you want to modify handling under braking (entry) without impacting the handling under acceleration (exit).

Managing a simracing team: Javier Álvarez, team principal of Positive SimRacing

Posted on by Jaap Grolleman

Javier Álvarez Benedí from Valladolid in Spain is the principal of the Positive SimRacing team, both spiritually as well as functionally; making the team grow with a business-like determination and can-do mentality. And it’s in this role that Javier is hugely influential in tutoring new sim racing talent.

What do you do during the day as your full time job?
In the government of the Castile and León region of Spain, I work a lot with people and teams as a strategist on long term plans and future innovations. And I’ve also been a scientific writer for over fifteen years.

How did you get started with Positive SimRacing?
In 2009 I was competing as a driver in Spanish sim racing championships, in sims like rFactor and games like F1 Challenge. Back than many Spanish drivers didn’t speak English, and didn’t have an international orientation, but I could see that sim racing would become an international eSport.

So, in 2012, I started to look for international championships, and joined Formula Sim Racing (FSR), in rFactor. There I found it was very difficult to start a team in that environment, because there was not enough drivers’ market. Basically, three teams dominated the grid and each had about ten drivers, which made very difficult the growth of new teams. But we had a different vision and philosophy: we saw the sim racing as something to be carried out beyond the sim racers, involving the general public and sponsors. Then, I met Jackson Wendt, and we started Positive SimRacing (PSR), maybe against the odds. Around this same time, the Royal Federation of Automobile of Spain hosted a sim racing competition, and we thought ‘let’s use this ‘, so we recruited some drivers from the top ten of that competition.

The first two years were a big challenge, because we weren’t such a strongly bonded team, more a group of drivers. For other teams it was really easy to steal our best drivers. Yet some people stayed and from this we grew into a team, more structured and moving up the ladder.

In 2014 we moved to iRacing, because there was more potential to grow and the competition was bigger. But because only three or four drivers joined the switch, we basically had to start the team from scratch again.

How does a team bond?
Some drivers, particularly young ones, may be very ambitious and don’t want plans spanning multiple years. They want to grow fast and become frustrated if they think they don’t have a good car setup. For them, it doesn’t matter if their driving style still needs work. With people who need results quickly like that, it’s nearly impossible to build a long term project.

But then, there are drivers that think long term and stick to the team. They have what you could call a philosophy, and we build a shared vision for the team. We’re very people focused. For instance, we don’t like to ‘steal’ drivers from other teams, we develop our own drivers. And that’s also why I think the PSR Driver Development Programme (DDP) with VRS is going so well. We invested lots of time in selecting the right people, and collaborating with drivers already in the team. The personal touch is what makes this strategy work.

How can philosophies differ among teams?
Maybe identity is a better word. There are teams who are elite and they only have to call a certain guy and he’ll join. Their main goal is to be at the limit and to win races. Although we won the SkipBarber 2K World Cup and took wins and podiums in other big events, we’re not at that level yet. We want to get there of course, but we need to develop the drivers and that takes time. This is our vision and we want to generate added value this way.

For this, we work together as a team. For instance, if a driver is in P4 and his teammate takes in P1, that’s like a win for both. We don’t have scenarios like Hamilton versus Rosberg in 2015-2016, or Hamilton versus Alonso in 2007. Everybody is committed to the success of the team. The identity and the sense of belonging to a project are essential parts of a team spirit, and I believe this is our niche.

Teams like Coanda don’t have a team manager role. Is this a different philosophy and
do you think one philosophy is better than the other?
I think it’s different, because Coanda may not have anyone in an official team manager role, however, drivers certainly assume leadership. It may not always be one and the same person, but they must have leadership within the team. They may have few but elite drivers, and they seem to aim to be an elite team with only a few elite drivers. A very good model, if you can make it work.

Coanda is perhaps the reference in modern sim racing, and beyond their sportive success and impressive results, their collaboration with VRS in improving the driver development constitutes a huge added value, which should be recognised by all the community.

Could you say you’re like a learning institution? To use an F1 comparison, like the
Sauber team?
Yes, that’s part of our philosophy, and it applies even to non-driving-related learning. I try to pair up Spanish drivers with English speaking drivers, so they learn English. And we focus on driving analysis and collaborations, like with VRS now. We think this is our added value to the drivers and the sim racing community.

How is the VRS DDP programme going?
We had over fifty applications for the DDP, but it was hard to select eight people. So we did extensive interviews and analysed profiles, and it looks like we’ve did a great job. Despite everybody having real life commitments and not always having 100% attendance in the practices or races, we’ve finished with two teams in top ten of the Blancpain Endurance Series.

Now we also have a junior programme with less intensity, and they’re improving at an incredible rate. They’re ready to join the main programme or be reserves (some of them are as fast as the top guys). So yes, I think the programme has gone well, in terms of results, as well as in terms of team building and driver development.

How do you manage that, how time consuming is it?
The management ‘overhead’ is significant. We had to spend a lot of work on this new structure, organising coaching and testing sessions, monitoring every driver individually, with individual meetings. This is huge! Can you imagine eight drivers and another eight drivers in the junior programme. Lots of work involved. But now we’ve appointed drivers as the ‘captain’ for each team, and this works quite well.

What prepares you for managing a simracing team? I mean, there’s plenty of tutorials
on racecraft, but nothing on managing a simracing team.
It’s not just life experience that helps, but also training. I mean, not just to practice and experience, but also through courses. I did this kind of training with my real life. I think my experience from work also helps, working with people with very different backgrounds helped me a lot.

Do you talk to other team managers?
Not really, with a few exceptions. And, until my knowledge, there is no team manager association. There was one in FSR, a team owner association, which is the only example that I know. However, team associations demand a clear common vision and managers working for the benefit of the group, which is very ambitious, if even realistic. So I don’t miss it. However, nowadays we have good contacts with managers of several teams, such as Blue Flag Racing and others. These contacts are usually very beneficial for the course of the competitions.

As the team principal. What do your tasks involve?
Team management is very demanding on time. For example, this morning I was scared to open Facebook, but maybe there are between fifteen and twenty messages. Some weeks I have to devote twenty or thirty hours. It’s like a second job. So we’ve decided we need to make it more sustainable, and that the team mustn’t depend on one person. If I can’t make it then the team shouldn’t stop. Two years ago we segmented the team into small and strongly bonded sections, and so for instance the Skip Barber team is six driver and one manager. I work with the managers, mostly all the time.

They can also work independently. In my dream, I would only decide on the strategy, budget and time. But often you’ve to talk and ask people what they want, and have the opinion of everybody. It’s always a balance between leadership and a full democracy.

What are difficult decisions you have to make sometimes?
To decide to let a driver join when he asks to join the team. When we were small, we always let everybody join. Now we’re careful, not to upset the balance. It’s difficult to really analyse someone and to anticipate, because when you say no to a driver you may have lost a good opportunity for the future. But then, if you decide to add a driver and he’s not a good addition to the team, he can upset the balance. So that’s one of the most difficult decisions.

Maintaining that balance can be difficult in another way too. In 2012 we had just started, but our philosophy changed a bit, so some of our core drivers sometimes feel a bit out of the team, and they don’t want to analyse their performance every week. But they still want to be part of the family, not all the new things, so we had to make that compatible with the evolution of the team. We had a lot of discussions to find a solution, so now we’ve started the ‘Positive Drivers Club’.

So what does it mean to you, when one of your drivers succeeds?
Several levels of happiness. First your project is succeeding and you get rewarded for all the work and patience, and also because you see your friends, people that you’ve helped and who’ve helped you, you see them succeeding. Maybe that’s the best feeling in life, when someone achieves something. When it has been a difficult journey, there’s also more happiness.

This applies to simracing, but maybe also to all of life?
For sure! Sim Racing is not only competition. It’s a sport that fosters personal and brain development, and there are scientific journals and that publish the benefits of gaming and development. Also concentration. I can do a race two hours without a mistake. But then I can’t sleep afterwards because my brain can’t sleep. And beyond that, as you say, it’s like everything in life. We put time, money, energy, to achieve something. Achieving something, at the end of the day, is the meaning of life.

What’s your goal looking forward?
For myself, I’d like my role to be less important so I can step back from day-to-day to focus on growing the budget and sponsors. It’s a matter of maturing the team. Now we’re working with the segmentation and managers, and I think in the next few years we can consolidate this.

As a team, we want to be in the iRacing World Championship Grand Prix Series, the Blancpain Endurance World Championship and the Skip Barber 2K Cup. Then we enter the top twenty, go to top fifteen. Maybe those are the last steps for the team, in terms of maturity.

You don’t aim to win those championships?
I think that’s too far. We want to be realistic. We would like that, but it’s too far. We don’t think this will happen within the next three years. For 2018 to 2020, the top 15 is a more realistic target, and later we will go for the top 10. Also, we are not obsessed with that.

David Williams on the lessons of online coaching

Posted on by Jaap Grolleman

One of sim racing’s veterans, expert on both race and vehicle dynamics, driver for Coanda Simsport, and one of the VRS coaches: David Williams from Southampton, United Kingdom. We catch up to talk about what it’s like to coach sim racing online.

First of all, how did you get into sim racing and this role?

A still from Clownpaint’s promotional video from Live for Speed, 2009

From as early as I can remember I’ve loved cars and racing. I watched a kart race in person as a small child, and it captivated me. Most of my toys were planes, helicopters or cars. Basically anything with an engine. I dreamt of becoming a Concord pilot, and later a Formula One driver. Growing up on the small Channel Island of Alderney, karting was non-existent, so racing games became my hobby.

My first proper sim was Live for Speed in 2006, where I joined the team of Clownpaint Gaming. We did quite well and won championships, and shortly after the teamed changed it’s name to My3id Gaming where we had further success. iRacing then came onto the scene and most of the competition moved there so we followed suit. Again, the team performed very well, ultimately taking the iWCS title with Hugo Luis and continued to evolve as a whole, later becoming 3id Motorsports.

My3id Gaming in Live for Speed
My3id Gaming in Live for Speed

At this time, wishing to pursue real motorsport, I entered GT Academy in 2011, where I made it to the national finals in person at Brands Hatch, but was beaten badly in the gaming element where random cars and tracks were chosen for three lap races. In 2012, I prepared much better, and made it through to the European final at Silverstone. This to date was the best experience of my life, pushing awesome machinery to the limit under the eyes of current and ex F1 drivers. At the end of the week I lost the chance for the final shootout for the overall win through the judge’s decision, but I have no regrets.

Later, 3id Motorsport’s team founder, Jack Basford, parted ways and took the name with him, and so a new team known as Coanda Simsport was formed from the remaining members. Taking a back seat from sim racing, I entered two more racing competitions, Want2Race and the Team HARD VW scholarship, both of which would prove valuable learning experiences with professional on-track tuition.

My3id Gaming in iRacing

Then in 2016, Virtual Racing School became Coanda’s title sponsor and partner, and Rens (Broekman), Martti (Pietilä), Martin (Krönke), and me took it on ourselves to become driving coaches, which was new to us all. I was confident in my knowledge of vehicle dynamics and racecraft, I knew the theory of going fast and dissecting that thought process, and wanted to share that with other people. I also had a good idea about race coaching, through the professional instruction in the various competitions I’d entered. The only thing holding me back was that I didn’t feel like presenting to people was a strength of mine, so I saw this as an opportunity to develop that.

What’s it like to teach someone online? I mean, you’re not in the same room with that person. Can you connect?

The benefit of real life race coaching is that you can be in the car with someone, so you can get a better feel for how they’re driving and how the car is reacting. But despite that, providing feedback while the student is driving can actually do as much harm as it does good. The advice maybe be good but it may also prove to be distracting. So in that sense, I think the format of coaching we provide is actually really good, because there’s enough time to carry out a very thorough analysis for which the student can take one or two key thoughts back out onto the track and manage at their pace. In addition, the VRS software is a hugely powerful tool, which is essentially an x-ray of the students driving, meaning nothing can be missed.

David (far right) on the 2012 Gran Turismo Academy

At what level should you look into coaching?

Many people have the preconception they need to reach a certain level before they can get coaching. But I believe that when you first start sim racing, that’s the best time to get coaching, before you’ve had a chance to enforce any bad techniques. The longer you continue with bad habits, the more difficult it will be to unlearn them. So my answer is; straight away!

Who would you like to teach?

Someone who is eager and willing to improve, and will do what it takes even if it requires a struggle. Many people write themselves off as not having enough “talent” before giving it a proper go, or make excuses for themselves such as blaming the setup. I also have friends who have a similar attitude which is very frustrating.

If you’ve learned the telemetry software, then why could you not go from there and learn yourself?

Yes, that’s very true. It’s worth saying I always try to make my student proficient with the software so they can analyse their own driving without me. However, it’s impossible to pass on everything there is to know about racing in one session, especially with regards to car dynamics and technique. I’ve had students who’ve had over ten sessions, and we still have plenty to talk about. Sometimes you just need a second pair of eyes in case you’ve missed something, and although you might be able to see where you’re slower, you might not understand why. Most of us coaches on VRS now have more than an year of experience, so we’ve already seen many different patterns and repeated traits among our various students, meaning we can more efficiently assist new students better than ever before.

What’s the most common area your students need to work on?

Since most are already quite quick and within a second of the datapacks, most laptime is typically found during the transition from braking to steering, or put otherwise; the period from when you start to release the brake, turn in and reach the apex. For good drivers, that’s where lots of time can be lost or gained. It’s a very challenging part to get right which is why it separates quick drivers from the best, and I always emphasise this in our video tutorials.

If you can analyse everything with VRS, then why isn’t everyone at the limit?

It’s difficult to say. First of all, it’s impossible to define a limit. There’s a physical and somewhat more unknown mental limitation to everybody, which I wrote about here. This limit is the last tiny bit of ability which separates the best, but I also think it’s true that 99.99% of drivers never reach their own personal limit. So if you want to go faster, you must just assume that you have what it takes. The moment you say to yourself; ‘I can’t beat Martin Krönke’, your failure to do so is guaranteed.. But if you say; ‘I reckon I can beat Martin, I’ll put in the hours and do what it takes’, then it just might happen. The problem for most people is that they don’t have that attitude. It’s a lot easier to just say ‘well, he’s just better’, and give yourself that excuse. Martin is relentlessly determined, and that’s the main reason why he’s so near the limit.

So even though we can measure and analyse everything, the single biggest component of getting better is being relentlessly determined. If you want to call that talent, then sure. I think that mindset is true for anyone who’s successful, regardless of which field its in. And the brain is a curious thing. Clearly not everyone is physically cut out to be a top level 100m sprinter, but our mental limitations are way more flexible than we can imagine. For example, I learned to juggle when I was twenty, even though before that I believed only certain people could pick it up. I learned it in over three painful weeks, during which I was constantly dropping balls after just a couple of throws. Eventually my brain rewired itself to the point where I went from focussing like mad on each throw to now being able to have a conversation with you while juggling. It’s now a fully subconscious skill. Driving fast is a skill which can be learned in a similar way.

On of the many videos by David on the VRS YouTube channel

Do all of your students improve after coaching?

This one is actually difficult to answer because not all of my students are immediately faster the next time they drive having had a session with me. Most of them do find time straight away, but for many it’s more about setting them onto a longer term process with the right ideas and goals for how to eventually become a much better driver. I think it’s very important to appreciate that knowing why you’re losing time, and understanding how to be better doesn’t guarantee an immediate improvement. Sometimes deeply ingrained techniques and bad habits must be unlearned and replaced with better ones, which take time and concentration, and will often temporarily worsen laptimes. The important thing is that my students attempt to apply the changes we discuss, because in fixing the fundamental technique, the laptime will come later.

Being an online racing coach is a relatively new job. What would be your advice to people who also want to become an online coach?

I think it’s important to be a fast and accomplished racer before considering coaching, for two reasons. First, I think it’s good for your credibility, because why listen to advice from a slow driver? Secondly, you’ll be conscious of the struggles you personally go through, en route on becoming a great sim racer. So you can pass that knowledge on. To be a good coach, that self awareness and understanding is absolutely critical. So if you’re fast and you understand why you’re fast, well then there’s no reason you shouldn’t be able to help others too.

5.6: Camber & Toe

Posted on by Martin Krönke

In article 5.5 we’ve covered ride height, and with this article we’ll continue the setup adjustments on the suspension, namely camber and toe. We’ll go over both of them together, as their effects are tightly coupled.

Click for full-res

Camber
Camber is the vertical inclination of the tire. Zero camber means that the tires are straight, perpendicular to the road and parallel to each other. With positive camber, the top of the tires points outwards of the car. With negative camber, the top of the tires points inwards.

Toe
Toe is the angle the tires are rotated around their vertical axis, looking at them from above the car. You have no toe if the tires are parallel to each other, along the direction of the car. You have toe-in when the tires point in towards each other, and toe-out when they point away from each other.

The effect of camber on available grip
As you go through a corner, the cornering force (as discussed more thoroughly in 5.3) causes the car to roll and the tire to deform, as it twists between the car which wants to go one direction, and the track that’s going the other direction. This is called lateral tire deflection.

With zero camber, the force on the tires are equally distributed along the contact patch when you’re standing still or driving in a straight line. This increases the available grip under straight line braking and acceleration (assuming no camber gain). Cornering with zero camber causes one side of the tire to unload, while the other side of the tire takes more load. This is unequal load distribution and lowers the overall available grip on the tire, just when you need it most: while cornering!

With negative camber, the force distribution along the contact patch is somewhat unequal while driving in a straight line. However, when cornering forces and carcass deflection come into play, they can negate the effect of negative camber, equalising load distribution along the contact patch. This maximises the available grip on the outside tires (which are the ones taking the heavier load), exactly the moment when the car is limited by its available grip. This is the exact reason why typically on road cars you’d use negative camber.

Tradeoffs of using camber
As always, nothing comes for free. While camber can help cornering, it causes additional heat, more tire degradation and uneven wear pattern on the tires. You should also realise that you are trading off traction on a straight line (braking and acceleration) with cornering grip. This means that the track profile is a determining factor on how much camber you want to run. In general, a track with mostly straights and low speed corners, you’d run lower camber; and on tracks with lots of bends or high-speed corners, you’d run more camber. And, as always with mixed profile tracks, you’d have to experiment different settings to see where you can gain more time; on the straights and low-speed corners, or high-speed corners.

Camber and vertical stiffness
Vertical stiffness of the tire is hugely tied with tire pressures, as discussed in 5.2. This is mostly to be considered on tires with high sidewalls. Having the tire inclined at an angle may cause the sidewall to deform a little. The effect is that of a softer tire without changing the tire pressure. As of time of writing, this really is only something to consider with two cars on iRacing, the Williams FW31 and the McLaren MP4-30.

Effects of toe-in and toe-out
There is one more effect of camber that we haven’t mentioned yet. If you roll a free tire at an angle, it would want to follow an elliptical trajectory instead of a straight line. In other words: an angled tire wants to turn. The force that causes this effect is called camber thrust. This results in a bit more friction, heat and wear, which can be offset by a toe-out adjustment. You can also use a toe-out adjustment to get the slip angles of the front tires in a more optimal spot. So you’d typically run some toe-out on the fronts.

Toe adjustments on the rear tires also have an effect on car handling. Toe-in on the rear creates understeer, which can help with cars that are oversteery on exit. The tradeoff is wear and heat in the rear tires. Toe-out on the rear is generally wrong, as you’re likely to get more oversteer on exit.

Up to you

While building a setup, go through the order of tire pressures, anti-roll bar, ride height and spring rates. If you have that set, experiment with the camber angles to find the optimal balance between speed in the corners and on the straight. Use toe-out on the front tires to counteract camber thrust, and possibly toe-in on the rear tires, to optimise handling.

5.5: Ride Heights basics

Posted on by Martin Krönke

Static ride height is one of the key setup adjustments, and also one of the easiest to get right. For example, for many cars converting a qualifying setup into a race setup (or vice versa) only means adjusting fuel and the static ride height. In this article we’ll explain what ride height entails, how you can adjust it, and how it affects other setup adjustment.

Static versus dynamic ride heights
Ride height (measured in mm or in) defines how far off the ground the chassis sits. Static ride height is what you configure in the garage. Dynamic ride height is the actual ground clearance at any moment in time as the car goes around the track. The dynamic ride height changes throughout a lap, for instance when a car goes over a curbstone, or when downforce compresses the springs. The dynamic ride heights also changes throughout a stint, for as the fuel burns off and the tank empties, the car becomes lighter and therefore ‘rises’.

Depending on the location of the ride height sensor (e.g. splitter, tire, etc) and its vertical offset, the ride height as measured in the garage (and as reported in telemetry) does not necessarily equate the actual ground clearance. For example, the splitter ride height sensor (on cars that have one) may be positioned a few centimeters above the bottom of the splitter. As a result, you’ll get a non-zero reading even if the splitter bottoms out. And obviously every single car is different, so the first thing you need to find out when you start setting up a new car is what “bottoming out” means in terms of ride height reading.

Purposes of changing the ride height
1: Lower center of gravity means less lateral weight transfer, which means more grip
For cars that are not very aero dependant the ride heights are primarily used to affect the center of gravity. A lower sitting car generally has better handling because a lower center of gravity means less lateral weight transfer. And we’ve discussed in 5.3, lateral weight transfer reduces the total available grip.

2: Balance between downforce and drag
For cars where aero is a defining factor in car setup, the ride height is the key to optimizing aero performance. Each car is different, but in general there’s an ideal ride height range that produces maximum downforce. Similarly, there is an ideal ride height range that minimizes aero drag. These two ranges may or may not overlap. Each car is different and it takes a bunch of experimentation with each new car to find out what works and what doesn’t. By statically and/or dynamically adjusting the ride heights, you can optimize the aero performance of the car.

3: Ground clearance
The final factor, relevant for both downforce and no-downforce cars, is clearance from the ground. You may want to adjust the ride heights to avoid bottoming out on bumps and curbs. Like discussed in the spring rates article, bottoming out can cause handling issues as one or multiple tires may become unloaded or lose contact with the track altogether, and it can also severely lower speed when the car is dragging onto the track.

Example
One of the most common setup scenarios is converting a qualifying setup to a race set. In most cases the additional weight due to the added fuel is bringing the car ‘out of tech’, which means it’s too close to the ground and isn’t legal to race. To pass tech inspection, you need to raise the ride height.

Typically, it’s best to keep a note of the target ride heights as they are in the qualifying setup and try to resemble those as close as possible on the race setup. In order to increase ground clearance, you’ll need to decrease the perch offset on each wheel, or increase the pushrod length (when available). Matching front and rear ride heights may be all you need to convert a qualifying setup to a race setup.

For cars where the gas tank is located far from the center of gravity of the car (e.g. the BMW Z4 GT3 has it’s tank fairly far back in the car), setting the race fuel ride heights could be trickier. As fuel is burnt throughout a stint the front or back of the car will get lighter, increasing the ride height. You may have to take this into consideration when determining the static ride heights with a full tank.

How suspension geometry affects ride height
Different simulators implement this differently, but in iRacing you cannot set the ride heights with one parameter. Instead, on each wheel you can adjust the spring perch offset, or increase the pushrod length (when available). Adjust these properties until your achieve the desired measurement for ride height.

Keep in mind that many suspension elements are connected. Significant changes to spring perch offset, or to pushrod length could also impact camber and toe. Each time you make a change to ride heights you should remember to also take a look at camber and toe. If your camber has changed, change it back to the old (desired) value. This may change your ride height again, so you may have to do a few iterations of ride height adjustment, camber adjustment, until you achieve the desired result. The same applies to each wheel’s toe-in.

When adjusting ride heights
You need to keep ride heights in mind each time you change any of the following:
Spring rates: Stiffer springs raise the car, softer springs bring it closer to the ground. When changing spring rates you want to make sure that you maintain the ride height from before the spring rate adjustment (otherwise you’ll be applying two changes to the car).
Tire pressure: The tire is effectively a spring, and significant changes in tire pressure affect ride heights too.
Camber & toe: As already discussed, camber and toe adjustments may affect the ride height. Modify the suspension geometry so that you achieve the new desired camber (or toe) at that same ride height.
Fuel load: Added fuel (per the example above, for full race distance as opposed to for qualifying) adds more weight to the car, which compresses the springs more, which reduces the ride heights. Each time you add and remove fuel you’d generally want to do so without actually modifying the static ride height (with some exceptions, depending on car or track).

Up to you

Once you understand what ride heights are and what interactions ride heights have with suspension geometry, you need to spend a lot of time testing and experimenting with different settings in order to find out what works with each specific car. And in a later article we’ll look more closely how to approach dynamic ride heights.

5.4: Spring rates basics (Formula Renault 2.0)

Posted on by Martin Krönke

Untitled-6(If you haven’t read article 5.3 about anti-roll bars, please do that first, because this article builds on the same basics of physics.)

From the Skip Barber, we progress into a faster and more complex car: the Formula Renault 2.0. The FR 2.0 has more setup options available, including an important one, which will vary greatly between circuits: the selection of front and rear springs. The spring rates hugely affect mechanical grip, but also aerodynamics, which may surprise you.

The most common type of spring used in race cars is the coil spring, which is typically installed together with a damper (see picture). For this article though, we’ll focus solely on the coil spring, and ignore the damper until a later article.

Spring rates and their effects
The spring rate is the measure of spring stiffness, and represents the amount of force required to compress the spring a certain distance. It’s measured in Newtons per millimeter (N/mm) or pounds per inch (lbf/in).

  • A higher spring rate gives a stiffer spring, so there’s less displacement per unit of force (the spring compresses less easily).
  • A lower spring rate gives a softer spring, which allows more displacement per unit of force (the spring compresses more easily).

A spring rate adjustment affects the following:

  • Weight transfer causes the ride height to change. For instance, during braking a car with softer front springs compresses more on the front, which pitches the car forward (dynamic reduction of ride height at the front). This impacts the mechanical grip of the car, because it changes the center of gravity. Aside from mechanical grip, an increased pitch (also known as rake) may also have aerodynamic effects, because the angle of the car changes. And during cornering, lateral forces cause the body to ‘roll’ which compresses the springs on the outside tires. Stiffer springs will reduce body roll. See the illustration for the difference between pitch and roll.
  • Aerodynamics will cause the ride height to change. For example, softer springs will compress more on the straights, as higher speeds generate more downforce. Lower dynamic ride heights are advantageous in reducing aero drag (unless the floor is scraping the track!).
  • The ‘bounciness’ of the car. For example, with stiffer springs, going over bumps and curbs may cause one or more tires to get momentarily unloaded or completely lose contact with the track, which would cause handling issues. Going with softer springs could solve the ‘bounciness’, but in return could hurt the pitch and roll attitude of the car, and may influence suspension geometry (such as camber), and consequently hurt aerodynamic effects and possibly cause aero-related handling issues.

3v2small

As we see, springs don’t control a single variable in a straightforward way. So, finding the optimal spring rate is a matter of finding the right trade-off between the above effects, which is often a compromise. In practice, when setting up the car, adjusting spring rates comes in handy when optimising aero effects, and the tradeoff is typically between aero related time gains (lower drag on the straights) and car handling (more downforce in the corners).

The nature of the track would typically determine the baseline you start tuning from. With this we mean the bumpiness of the surface, and the lengths of the straights, and whether there are many fast or slow corners.
On tracks with fast straights and many flat, slow corners (such as Gilles Villeneuve, Montreal), you’d like to start with stiff front springs and soft rear springs. Such a setup would produce more rake (and downforce) in the slow corners and less drag on straights.
On tracks with short straights and a wide range of corner speeds (such as Motegi), you’d like to start with stiff springs on both the front and the rear. This would allow you have a car with more consistent aero performance in all corners regardless of speed.

Most tracks are in-between, so you’d want to pick a baseline for the overall profile, then look at the track specifics. For example, a bumpy slow track like Sebring could need softer springs.

Applying it to the FR2.0
Let’s get to know the suspension layout for the FR2.0. As you can already see in the setup-screen, there is only one center mounted spring and damper in the front, with non adjustable ARB. In the rear are two separate spring and damper units. Unlike the front ARB, the bar in the rear is adjustable in stiffness.

fr2.0-illuUntitled-1

This single spring design at the front is called a monoshock. It is characteristic of a monoshock that the front spring has no effect on roll-stiffness. It only provides stiffness in heave (vertical) motion. This essentially causes spring stiffness to have no significant effect on the mechanical balance (lateral load transfer distribution and roll) of the car. And so the front roll-stiffness is solely controlled by the front ARB, which is adjustable in the real car, but is fixed in iRacing.

In contrast, with the two springs at the rear of the car, roll stiffness is influenced by both the adjustable rear ARB and the rear springs. In practice, you wouldn’t make spring rate adjustments to affect roll-stiffness. If a spring rate adjustment (for a different reason) results in undesired impact on roll-stiffness, you’d counter that effect with an ARB adjustment.

The regulations allow the FR2.0’s ride height to be very low, as a consequence you can run the stiffest front springs and still achieve your desired front ride height. This simplifies the front spring rates setup. In general, aim to run the stiffest springs that still allow you to go over bumps (if a curb is giving problems, you may not want to counter it through setups, but just avoid hitting it). Finding out the optimal rear spring rates will mostly be a matter of how much you want to vary the dynamic ride height in the back. Stiffer rear springs give you a more consistent handling through the corners, while softer rear springs will give less drag on the straights.

Over to you

Try fiddling with the spring rates, and see if you can improve your laptime with it. For instance, load a session at Silverstone Historic. The circuit has fast corners and fast straights, so a compromise is needed between the two baselines suggested above. You pick either baseline as a starting point, for example stiff front and soft rear. From there stiffen the rear and see if it leads to laptime improvements. Because the rear spring rate changes multiple parameters of the car, such as the ride height, you could correct those accordingly to maintain the same static ride height. You can also use the anti-roll bar to help restore the balance of the car, just never change it together with the spring rates, because it makes it hard to tell which change is causing which effect.

5.3: Anti-roll bar basics (Skip Barber F2000)

Posted on by Martin Krönke

Untitled-1After the tyre pressures, which we handled in 5.2, another significant setting to tweak on the Skip Barber is the anti-roll bar (ARB) in the rear. First of all, you need to understand what an ARB is and what it does to the car.

The red component in the illustration below is an anti-roll bar, which nearly every racing car has on its rear and/or front axles. The ARB connects the suspension elements of two wheels on the same axle. As a result, as soon as one wheel moves up or down, the other wheel is forced to follow that motion. However, the ARB is essentially a torsion spring which stores some of the energy when twisted, so not the entire movement of one tire is transferred to the other.

arb3

To give an example of an ARB’s importance: When a car without an ARB installed goes through a fast right-hand corner, the inertia forces the car to lean to the left side, which is on the outside of the corner. This is because the mass of the chassis is not willing to change direction, while the tyres that grip to the surface are. Relative to the chassis, the left tyres move upwards, the right tyres move downwards, causing body roll. Try to visualise this in your mind.

  1. The main purpose of the ARB is to change the roll stiffness of the axle it’s installed on, which has two important implications:
    The more horizontal a car goes through a corner, the better the chassis is at creating downforce. We’ll cover this in a later article, since here we’re covering the low downforce Skip Barber car.
  2. The ratio of roll stiffness between the front and rear axles affect the balance of the car, especially its tendency to under- or oversteer. Unlike downforce, this is highly relevant for the Skippy.

To understand how balance is affected, we need to understand that as vertical load on a tyre is increased, the coefficient of friction of that tyre decreases. You still get more grip, but proportionally less. This is known as load sensitivity.

graph

Let’s work through an example, using the chart above. At 400 kg of vertical load on a tyre, the coefficient of friction is 1.25. By multiplying the two numbers, you get the amount of friction force provided by the tyre:

400 x 1.25 = 500 kg (single tyre)

If we have a perfectly balanced axle where each wheel is loaded with 400 kg, the total available grip at that axle is:

(400 x  1.25) + (400 x 1.25) = 1000 kg (axle)

Cornering causes lateral (left/right) load transfer at each axle. Vertical load will increase on the outside tires and will decrease on the inside tires. Continuing our example, let’s assume that due to lateral load transfer the vertical load on the left tyre becomes 500 kg, while the load on the right side becomes 300 kg. The coefficient on the left tyre decreases from 1.25 to 1.11, while on the right tyre it increases from 1.25 to 1.35.

500 kg x 1.11 =550 kg (left tyre)
300 kg x 1.35 = 405 kg (right tyre)
550 kg + 405 kg = 955 kg (axle)

So while the total load on the axle remains the same (800kg), the total available grip is now only 955 kg. Just when you need grip the most!

Now we understand how an axle can lose grip under cornering, and is this precisely what causes handling issues. When the available grip of the rear tyres is exceeded first, the car goes into oversteer; when the grip of the front tyres is exceeded first, the car goes into understeer. An ARB can balance this out.

Using the ARB to balance the car
A softer ARB causes less lateral load transfer on its axle, compared to a stiffer ARB. This can improve the balance of the car, and increase overall grip on the axle as shown in the earlier example. The ARB stiffness can also determine the lateral load transfer between the front and rear axles, even if a car only has one ARB, like the Skippy, which only has one on the rear.

A stiffer rear ARB causes more of the lateral load transfer to be distributed to the rear axle. Softer rear ARB means more of the lateral load transfer is distributed to the front axle. A stiffer rear ARB thus reduce available grip at the back while increasing it at the front, hence, making the car more oversteery and less understeery. Conversely, softening the rear ARB increases available grip at the back while decreasing it at the front, hence, making the car less oversteery and more understeery.

Controlling how much lateral load is transferred on the front versus rear axle is a balancing act, to optimise how much grip is available at each axle. Tuning the rear ARB on the Skip Barber car is mostly a question of driver preference: If you find the car too unstable for your liking, you can try reducing rear ARB stiffness. If you find the car unwilling to turn, you can try stiffening the rear ARB.

It’s important to note that tuning the ARB will only make a difference if you are utilizing the traction circle, as explained in 3.1. If you ask too much of the car (overall G’s), the ARB won’t help. If you ask too little, you won’t notice any difference in handling.

Up to you

Get the Skip Barber out for a spin, and see if you can adjust the ARB to your liking! See if you feel the effect of it, and try to visualise the forces working on the car as you go through the corners.

For further explanations on the matter of ARBs, please see the more advanced chapters of this guide, which we’ll publish soon.

5.1: To setup or not to setup?

Posted on by Martin Krönke

vrsAs you progress through your iRacing career, competition is fiercer and you’ll need to use all the tools in the box to find the edge over your rivals. One of these tools is car setup. And while most beginner series have friendly communities with lots of setups being shared on the forums, the willingness to share setups significantly drops off at more competitive series. Especially at the top level of sim racing, setups are seen as highly guarded intellectual property. Thus, having a basic understanding of car setups becomes a very useful asset in your sim racing career.

But before you start, here are few questions you should answer to ascertain whether diving into setups is the best use of your time:

  • Are you willing to study and learn how to create a setup from scratch?
    This is not an “if this, then that” kind of guide. Setting up a car is about trade-offs within the limits of physics. Gaining proficiency in car setup is a process that requires you to experiment and analyze a lot.
  • Are you able to consistently hit lap times within 0.2s of your fastest lap?
    If not, then your biggest gains might not come from setups. In road racing, if you’re 3 seconds off the pace on a road track, probably only 0.3s is down to the setup. In oval racing, it’s much easier to learn the tracks, so car setup is a quite significant factor in open setup series.
  • Can you tell whether time loss was due to car or driver?
    You should be able to distinguish driver errors causing understeer, from a car setup change causing understeer. This means you should already be a driver capable of in-the-moment driving analysis.
  • Have you fully developed your driving style?
    Especially in road racing, driving style is typically a much more significant factor in lap times than car setup. Unless you are within 0.2-0.5s of your fastest teammate, or a VRS datapack, you are probably better off working on your driving style. On the flip side, if you have deeply ingrained old bad driving habits, it may be more efficient for you to tune the setup to your driving style. But still, we’d recommend that you try fixing your driving style first.
  • Are you used to driving the car which you want to setup?
    If you hop in a new car, it usually takes a bit of time getting used to it first. Pick up a decent setup (from the forums or a VRS datapack) first and focus on driving style until you are able to turn competitive lap times in the chosen setup.  

If you can answer all these questions with a definitive yes, then this guide is for you.

We’ll get started with the basics that apply to any car and we’ll progress to more advanced setup topics, which are only applicable to high-end cars. We’ll start with the Skip Barber RT2000, as it is the first open-setup car for most road racers, and also a car that’s understandable and sensitive enough to observe setup differences with. Then we’ll move on to the Formula Renault 2.0 which offers a lot more setup options. Also, the trade-offs between different adjustments become quite interesting in the FR2.0. Finally, we’ll look at a high-end, high-downforce car in the HPD ARX-01c.

Ready to get started? Head on to 5.2 where we focus on tyres.

3.4: Fundamentals: Braking technique

Posted on by David Williams

Having learned about the traction circle, the optimal racing line, and car control, the next chapter in this series looks at braking technique. Your brakes serve two purposes. The first is pretty obvious: to slow the car down. The second is more subtle, which is that brakes offer a method of controlling weight transfer and balance from corner entry to apex.

Straight line threshold braking
To brake as late as possible, you want to reduce the time spent slowing the car to a minimum. Achieving this requires you to exploit nearly 100% of the available grip from the tires in a straight line. This is known as threshold braking. It’s the brake pressure required to reach the point at which the tires are just on the edge of locking up, and no more.

We’ll divide braking technique up into non-downforce cars, such as the Mazda MX-5, Skip Barber, Porsche/RUF and Lotus 49, and downforce cars, such as the Formula Renault 2.0, the HPD, and the McLaren MP4-30. Even if you drive a downforce car, read the non-downforce section first.

Non-downforce cars
Don’t be afraid to brake too hard when you first hit the pedal from high speed. This is when the wheels have the most energy and are least likely to lock up. From this moment on, reaching threshold braking is a case of delicate modulation, and very much a feel thing, requiring practice.

With the above in mind, there are a couple of sources for feedback which can help out in the “feel” department. Firstly it’s a matter of listening to the tires, or in the case of open wheelers, visually seeing them lock up. It’s also possible (but more difficult) to feel changes in load through force feedback and rpm changes in the case of rear locking. Learn how the tires sound just before they lock up, and avoid braking harder than that (to help, you can raise the tire volume in the options menu). The required pressure will be consistent and repeatable regardless of speed assuming tire wear is discounted and the circuit is flat. This is therefore something which can be trained into your muscle memory over repetition. It’ll be obvious in iRacing when you’ve locked up, the tires will screech, the car won’t turn in the case of a front lock up, and you may see visible smoke.

VRS app telemetry braking trace before T5 at Okayama in the MX-5:braking trace - T5 Okayama

Downforce cars
Fundamentally the same rules apply to downforce cars, but it’s key to understand that the level of grip is speed-dependent. At high speed the car will produce more downforce and therefore the tires will have more grip when compared to travelling at low speed. When you start braking therefore, your speed is obviously greater than when you finish, and the grip level in turn decreases as you continue to brake. This of course means the required threshold braking pressure will decrease in connection with your speed.

How this typically works in practice: Slam the brakes to reach threshold braking quickly, then “bleed” off the brakes at the same rate as the car slows down and the downforce comes off.

Turn 1 at COTA with Martin Krönke in the MP4-30:
braking trace - T1 at COTA

A common mistake in racing downforce cars is not braking hard enough initially. Drivers tend to brake with an initial force which causes the tyres lock up at the end of the braking zone, failing to take full advantage of the extra grip early on.

ABS
Many modern race cars such as the GT3 class now feature driver aids such as traction control and ABS. Whilst ABS prevents locking of the wheels under heavy braking – especially when turning at the same time – it shouldn’t be relied on. Correctly carried out threshold braking is still more efficient, as ABS tends to work in a pulsating manner meaning the tyres lock up very briefly, reducing the braking performance and causing additional tire wear and heat. However, threshold braking is much easier to achieve in ABS equipped cars, as you get additional feedback – when engaged the ABS causes significant vibration which can be felt through the wheel with force feedback. Reduce brake pressure so you only have a subtle hint of this.

Understanding threshold braking while steering
Braking is further complicated when turning into a corner, and if you refer back to article 3.1 “The traction circle” you will know that in order to stay within the limits of the available grip at the tyres, you must reduce brake pressure as you steer, and eventually come off them at the point at which 100% of available lateral grip is being exploited (typically the apex of a corner).

Trail braking
The earlier paragraph is often termed “trail braking”, and is why you’ll see a fast driver bleed off the brakes as they turn into a corner even in cars without downforce. Proper trail braking technique however takes this a step further, and involves continuing to hold onto the brake pedal very deep into corners, typically right up to the moment at which the driver starts to apply throttle. This form of trail braking isn’t so much used to slow the car down but instead as a control method to maintain load on the front tires and reduce understeer from corner entry to apex. You can see evidence of this in Martin’s telemetry from the trace earlier in this article in his reluctance to fully release the brake pedal.

Here we can see David trail braking into T1 at Zolder with the BMW Z4. We have divided the braking phases as shown:
braking trace - T1 at Zolder

A: Threshold braking – bleeding off with downforce level
B: Exploiting the traction circle – reducing brake pressure with increasing steering angle
C: Trail braking – continuing to hold the brakes at 5-10% until applying exit throttle

Up to you:
These techniques will take a lot of practice and repetition before they start to become natural, and initially you may be worse off. Focus on one technique at a time and refer back to the VRS app for telemetry to review your efforts.