Handicap Racing

At iRace we work hard to promote hard, fair racing. We want the drivers in our series to develop, and to gain the maximum benefit from racing with us. We've evolved a variety of different race formats, including rolling starts, reverse grid races, and perhaps the most beneficial of all, the handicap race format.

The handicap race format allows cars and drivers of all different speeds to race together, and for everyone to have a chance of winning. The basic concept is that the slowest cars start first, with faster cars released in groups at calculated time intervals. In Acuform Muscle Division and K-Mac Touring Car Challenge, we spend a lot of time trying to perfect the groupings, and the time delay. We work out the delay based on the average laptime for each group (taking the fastest time for each member of the group and then averaging from there), and such that the groups should all come together at around 80 percent race distance. This leaves the remaining 20 percent of the race for overtaking. For example in a 10 lap race, we'll try to get everyone to merge on lap 8, with laps 9 and 10 where all the action happens, and the final race result is decided. Occasionally things work out perfectly, and we'll have the whole field covered by 10 or 20 seconds as they greet the chequered flag.

How can drivers maximise their chance of winning? Consistency. If you are able to put in the same laptimes lap after lap, you'll give yourself the best chance of being at the front at the finish. Spin, make a mistake, or lose time on the odd lap trying to hard, and you'll struggle to either: a) hold onto the lead you have (if you started at the head of the field), or b) make up ground on the slower cars ahead. Consistency is the key.

Some other top tips include: try not to lose time being overtaken, the best option is to brake a little early and let a faster car by - this will lose you the least amount of time (unless it's the last lap and you have a chance of keeping the lead!), if you are chasing, be patient - it's tempting to go hell for leather trying to catch the cars you can see so far ahead, but try to pace yourself, drive your markers, and put in smooth consistent laps (pushing too hard risks making mistakes and losing time). If you are out front early, just put your head down and go, go, go.

When you get it right, and handicap race can be the most fun you'll ever have in a racecar. It offers racecraft, strategy, overtaking, being overtaken, and best of all, a thrilling finish.

We were able to put together the following video, showing the perspective of cars at either end of the field as they make their way through a handicap race. Enjoy!

The Art of Overtaking

Overtaking is a tricky business. It’s part of motorsport, and one of the most exciting aspects. With the diverse range of cars in the Independent Race Series we see even more overtaking than most other circuit racing.

Done poorly, overtaking can cause unnecessary delays for both cars, and in the worst case damage and DNFs (think Vettel and Webber at Turkey last year). Done properly, and with respect, overtaking can be safe, efficient and exciting (think Webber and Hamilton carving through the field at China this year).

The aim of any overtaking manoeuvre is for the overtaking car to safely pass the car in front, and for both cars to continue on. Our previous feature article looked at how to avoid contact in general, click here for a refresher. Building on that information, let's have a look at some of the complications of overtaking.

For the overtaker:

  • The car to be overtaken is in your sights for a long (relatively) period of time - your attention is out the front of your car, so you see the car ahead for a significant period of time. This can lead to a failure to appreciate that the car you are approaching does not have the same awareness of your presence as you do of his.
  • You may be behind the car for long enough to see a sense of his rhythm. If the car ahead deviates from the normal rhythm you have observed, you may misinterpret this as him either giving way to you, or a small lose that you can take advantage of. This can cause problems if it was simply a small error or missed gear, wires can get crossed, and contact can occur.
  • Frustration may set in, and you may start to get impatient.


For the overtaken:

  • Your attention is naturally on the road ahead. Nobody drives fast by looking in the rear view mirror. A faster car may suddenly appear in your mirror (if you check it), or alongside you. In your eyes he came from nowhere, but in his eyes he was watching you for some time.


How to be passed

There is a right way and a wrong way to be passed, or perhaps better phrased as a fast way and a slow way. The wrong way is to position yourself such that the only way for the faster car to get through results in contact, or at the very least in both of you going off line and losing time. The right way involves either being passed on a straight, or on the approach to a corner. If the overtaking car is faster in a straight line, the pass on the straight is simple. To allow a faster car through on the approach to a corner, simply brake a little earlier, or for a little longer, while holding the normal line. This will allow the overtaking car through on the inside, and the instant he is past, you can release the braking pressure and take up the normal line an inch from his tail (watchout for cars following closely behind the overtaking car!) - you lose VERY little time by using this method, and reduce the likelihood of contact.

Last Word

The last word on this topic comes from the fantastic book "Think Fast" by Neil Roberts:

  1. It is your responsibility to see and avoid everything, everywhere, all the time.
  2. The car in front of you owns the entire width of the track, even if you are alongside, and even if you are about to lap that car. The car in front of you has the right to use any and all of the track, the curbs, and the grass, so any contact is your fault. The instant that the nose of your car edges ahead of the nose of the other car by one micron, the roles reverse. Now you own the entire width of the track, and you can drive anywhere you want.
  3. The way that you deal with nearby cars reveals how much you can be trusted.


DSC_5016Driving race cars on the limit is a challenging activity. Add in variable track and weather conditions, plus other cars sharing the same piece of road, and it becomes a constantly changing and formidable task. Most of the time we get it right, and everyone is able to keep to their own piece of the track. Occasionally though, cars come in contact.

Contact between cars is obviously undesirable, and something that is not taken lightly by officials. There are some simple things to keep in mind though to help keep you out of strife, and ensure you're operating in the spirit of the Independent Race Series and maintaining harmony with your fellow competitors and respective their and your own investment.

Avoid contact in the first place

Seems pretty obvious, and the most effective way to do this is never to overtake anyone - obviously that is not a workable solution (nor one that we would encourage), so a better approach is needed.

Know your fellow competitors. You can start working on this before you even line up on the grid for a race. Other drivers racing line, braking points and on track demeanour will certainly be subtly different to your own. You can observe these things in practice and qualifying sessions, and you should work to build a mental database of what to expect from your competitors when you encounter them on track. Knowing what to expect from them will mean you are prepared if you see the other guy brake a little earlier, or turn in a little later. It will help you be ready for it, take advantage of it, and avoid contact.

Know the track. When you are practicing, as well as just learning the fastest way around a circuit, look for good, effective overtaking places. Generally you'll be looking for somewhere you can get a better run out of the preceding corner or a tow on the straight, to set yourself up in a favorable position approaching the braking zone. A long braking zone is good, and you'll also want a section where you can make the pass stick (where you can exit the corner firmly in the lead and pull a small gap on the next section). Sections like this are rare, so sometimes you need to look for the best compromise and file it away as one of your preferred overtaking places.

Know your car. The most important part of this is knowing your cars strengths relative to the competition. Is it lighter and nimbler? Or more powerful and stable? This will help you know where the best place to pass might be.

Know your limitations. If you consider all of the above, and know your own limitations: how late you can brake, how fast you can take each corner, how tight you can hold your line and so on, you should be able to successfully overtake without making contact.

Know when to back out. Sometimes you can line the perfect pass up, but the other guy doesn't see you, or is baulked by something out of your control - be on the lookout for this, and know when to play it safe and try the pass on the next lap, or on another corner.

If you make contact, apologise

The person you have made contact with may not always be in the most receptive mood, depending on the outcome (but hopefully you've applied most of the principles above, and the consequence of the contact was minor), but generally the sooner you can apologise, the more it means. If you gained an advantage on the circuit as a result of the contact, and you can redress the situation, do it as soon as you can - don't slam your brakes on in front of the other car, but blend out of the way and allow him back past (a good example of this can be seen here, where Daniel Flanagan inadvertently contacts Tony Grant and slows a couple of corners later to allow him back past).

If you have the chance to redress things during the race or not, you should always make the effort to apologise to the other driver in person.

Never make deliberate contact

Deliberate contact will not be tolerated in the Independent Race Series, you may receive anything from a warning to a complete ban from the series.

The role of the driver being overtaken

No racer likes to be overtaken, but there are a few things to keep in mind to minimize the likelihood of contact. Be aware of all the considerations mentioned above. Know what is going on around you - checking your mirrors will let you know if a car is gaining, the rate of closure should give you an idea if you should expect a move at the next corner. You're generally within your rights to defend your line, but you should not change your line once the other car has achieved an overlap. If you see another car going for a move that will clearly never work, sometimes it's best to just move aside for a moment and allow that car to go off on their own (rather than taking you with them).

Final thoughts

Racing is a tricky business. Racecars are expensive. Contact is something we should do our best to avoid, and if the worst does happen, apologise and endeavor to redress any advantage it may have gained you.

Most of all, remember these iRace principles:
We care about safety
We care about each other

Flagging Attention

Motor racing is dangerous. It's printed on every circuit admission ticket you've ever seen. But really, motor racing is for the most part a safe activity. Part of that safety is directly attributable to the communication and control of the Race Control team.

From time to time Race Control need to communicate directly with a driver or drivers. And the only way to do this is via flag signals. It's important that everyone knows exactly what each flag means, so the messages that are passed aren't misunderstood or ignored.

Below is a short refresher on what each flag means. This information can also be found in the iRace Series Rules & Regulations.


Black Flag

Driver Action:
Enter the pitlane on the next lap

Reason for Use:
Shown when there has been an infringement or other problem


Black and White Diagonal Flag

Driver Action:
Correct driving behaviour or standards

Reason for Use:
Warning flag shown when driver is behaving in an unsportsmanlike manner


Chequered Flag

Driver Action:
Cease racing and return to pits or paddock

Reason for Use:
Marks the completion of the race or session


Blue Flag

Driver Action:
Check mirrors and prepare to be overtaken

Reason for Use:
Usually waved when a faster car is approaching or attempting to overtake a lapped car


Green Flag

Driver Action:
Resume racing

Reason for Use:
All clear ahead (usually after an incident zone)


Black with Orange Disc Flag (Meatball)

Driver Action:
Stop at pit on the next lap

Reason for Use:
Vehicle has a mechanical problem which may cause a safety hazard


Red Flag

Driver Action:
Stop racing, return to the grid or pitlane (as directed), be prepared to stop at any point, NO OVERTAKING

Reason for Use:
The race or session must be stopped for safety reasons, usually an on-track incident


Red and Yellow Striped Flag

Driver Action:
Use caution the racing surface is degraded or slippery

Reason for Use:
The circuit is breaking up, or oil/coolant or debris on surface


White Flag

Driver Action:
Use caution, slow moving vehicle on the circuit

Reason for Use:
Slow moving racecar or service vehicle on the circuit


Yellow Flag

Driver Action:
Slow, use caution, be prepared to stop or take avoiding action, NO OVERTAKING

Reason for Use:
An incident or obstruction on the circuit. Waved if partial blockage of the track, double-waved if significant blockage

Featured Product Wrap Up

featured product.pngWe've been slowly adding some articles to the Featured Product page, and have some great reviews and tutorials now available:

Head over and have a read, and if there is a product you would like to see reviewed, please get in touch by clicking here.

Roll On: How an Anti Roll Bar Works

Most racecars are fitted with at least one anti roll bar. Anti roll bars are a simple and effective way to fine tune the handling characteristics of a racecar, and yet they are often poorly understood and sometimes used incorrectly. This article will attempt to explain the three things an anti roll bar does, and why you might want to do these three things. Finally, it will attempt to provide an explanation of what change to make to your anti roll bar to achieve the result you want.

There are some technical explanations missing from this article. This is deliberate. We want to keep things as simple as possible, focussing mostly on what anti roll bar change to make to achieve the right result. For more in depth coverage of this topic, you might like to refer to Allan Staniforth's excellent book: Competition Car Suspension.

What does an Anti Roll Bar do?

Resists Roll
The anti roll bar (as is implicit in the name), resists roll. As a racecar drives through a corner, the anti roll bar works to resist compression in the outside suspension, and also works to resist extension in the inside suspension.

Increases Spring Rate
The anti roll bar increases the effective spring rate in the outside suspension when the car is going through a corner.

Transfers Weight
In a cornering situation, the anti roll bar works to transfer weight from the inside tyre to the outside tyre. If anti roll bars are fitted front and rear, the relative strength of the anti roll bars at each end will also work to transfer weight from front to rear or vice versa.

What does all this mean?

Resisting roll is generally a good thing. It maintains the racecar in a relatively stable platform. For an aero sensitive car, it will also keep the wings working at or near their optimum. Most cars also experience some camber change as the suspension moves through it's travel. Any change in camber from optimum means less of the tyre is in contact with the track - this means less grip. The roll resistance provided by an anti roll bar can help reduce this by keeping the tyre closer to optimum camber.

Increasing spring rate leads us into how we use the anti roll bar to tune the suspension. The static spring rate at each end of the car is normally selected to keep the tyre in contact with the track surface as much as possible. Too soft, and the suspension will deflect to the point where the bodywork/floor contacts the ground, or the suspension reaches the end of its travel. Too hard, and the tyre will spend most of its time skipping across the surface. If we go to the extreme, to solid suspension, the tyre will quickly become overloaded and skate through every corner. So, if we assume that the spring rate is already at optimum, an increase will result in some reduction of grip.

Weight transfer means that more of the cars total weight is carried by one wheel than the other. If we imagine a car that, when parked, has equal weight on every corner (say 250kg), all tyres will provide the same amount of grip. As this imaginary car enters a left hand corner, some of the weight is transferred to the outside tyres (the exact amount will depend on roll centre heights and other things beyond the scope of this article). If the anti roll bars front and rear are the same, the weight transfer at the front and rear will be the same. We now have 300kg on the right hand tyres, and 200kg on the left hand tyres. If we were to simplify things, we would assume that this means we now have 20% of our grip coming from each inside tyre, and 30% from each outside tyre - this is not accurate, the relationship between tyre load and resultant grip is not linear. The actual figures may be something more like: 15% from each inside tyre, and 35% from each outside tyre. If we stiffen the front anti roll bar (but leave the rear the same, the result may be something like: LF 180kg, RF 320kg, LR 200kg, RR 300kg. Because the load/grip curve is not linear, the amount of grip at each tyre will be something like: LF 10%, RF 38%, LR 15%, RR 37%. If we then compare total front grip to total rear grip, we see there is 48% at the front, and 52% at the rear. Stiffening the front anti roll bar has given us a higher proportion of grip at the rear. The car is now more likely to understeer.

Putting it into practice

There are a number of ways to remember what effect an anti roll bar change will have.

You may like to think of it as putting a stiffer anti roll bar at one end of the car, will 'tie-down' the opposite end, ie; a stiffer bar in the front will yield more rear grip.

Or you may consider that the anti roll bar reduces compliance at the end it is used, and reduces grip at that end of the car.

Both of these explanations overly simplify what is actually happening, but they do help to remember which way to make changes when adjusting setup at the circuit.

Essentially, to reduce understeer, you may try using a stiffer rear anti roll bar (trade offs will be reduced rear grip, worse power down for RWD cars), or a softer front anti roll bar may be more appropriate.

To reduce oversteer, go for a stiffer front anti roll bar, or soften the rear anti roll bar.

Further Reading


Remember, you are responsible for the consequences of any changes you make, and any adverse outcomes. This article is provided for reference only. Neither iRace or the author offer any warranty or any liability for any damage or injury caused by tweaking any racecar.

New Years Resolutions

4A3B45AB-6BBA-4C28-BF7A-459BD30E704A.jpgNobody is infallible, and mistakes can happen. Sometimes the consequences are minor, but in racing the consequences can sometimes be a little more dire. To help you out with your New Years Resolutions, we thought it might be timely to put together a top ten list the most common 'rookie errors' made in racing, so you can vow to avoid them!

  1. Forgetting the Bonnet Pins
  2. Forgetting to adjust the Tyre Pressures
  3. Running Out of Fuel
  4. Incorrectly Tensioned Wheel Nuts
  5. Oil Surge
  6. Flat Battery
  7. Something Left in the Boot
  8. Soft Brake Pedal
  9. Steering Wheel Off Centre
  10. Left Something Important at Home

1. Forgetting the Bonnet Pins

This has happened to many a sedan-mounted racer. It usually occurs as the result of an interrupted routine, or lowering the bonnet, with the person thinking they will come back to it, or someone new to the team. As the racecar heads out on track, the airflow lifts the bonnet, usually smashing it into the windscreen, often damaging the bonnet and the windscreen. It's also not very good for the driver's vision, and heavy braking almost never causes the bonnet to close again. It usually means at best a trip back to the pits, at worst a new bonnet and windscreen.

To avoid this, have a rule: anytime the bonnet is closed (for ANY reason), the pins are fastened. It's also a good idea to add a check of the bonnet pins to your pre-session checklist.

2. Forgetting to adjust the Tyre Pressures

New tyres are awesome. Wasting their best grip is not awesome. The easiest way to do this is to forget to reset the correct pressures after new tyres have come back from the tyre truck and been fitted to the car. If the pressures are too high, the crown of the tyre will overheat and the tyre will feel greasy. If the pressures are too low, the tyre will move around a lot, and probably overheat (and feel greasy).

To avoid this, add a final check of the tyre pressures to your pre-session checklist. Make sure your mechanics know what the cold pressures should be.

3. Running Out of Fuel

This has happened to more people than would care to admit it. It's usually blamed on fuel pressure or fuel pump problems. That almost always means the car ran out of fuel. If you're very lucky, the car will stutter and allow you to limp back to the pits for a refill. If you're unlucky, the car will stop working on the track, taking you out of the session or race altogether.

To avoid this, designate one of your crew as 'fuel man'. Add a confirmation of fuel state to your pre-session checklist. Do not rely on fuel gauges. For some types of tank a 'dipstick' may be appropriate.

4. Incorrectly Tensioned Wheel Nuts

There are three scenarios here. Nuts can either be too tight, too loose, or missing altogether.

If the nuts are too loose, they will likely vibrate looser, allow the wheel to move on the hub, which will cause more vibration and expedite the further loosening of the nut, and ultimately cause the wheel to fall off. That is bad.

If the nuts are too tight, as things start to warm up and move around, the wheel studs will probably break. Once a couple break, there is more load on those remaining, and the wheel will fall off. That is bad.

If there are studs or nuts missing, eventually the remaining studs will give up and the wheel will fall off. You know what that is. Bad.

To avoid this: tension the wheel nuts at the beginning of the day, when the wheels are cool. Add it to your pre-session checklist. Avoid the temptation to tighten wheel nuts when the wheels/brakes/etc are hot.

5. Oil Surge

Oil surge is common to wet-sumped, production-based cars (and, believe it or not, some purpose built cars too). It happens when the car goes around a corner fast, generates lateral forces, and causes the oil to move to the part of the sump on the outside of the corner. Invariably the car will also have rolled to the outside of the corner, exacerbating the problem. When the oil moves, it sometimes moves away from the oil pump pickup (usually placed in what is, under normal conditions, the lowest part of the sump). If the pump picks up air, it pumps air to the bearings, and air doesn't do much lubricating. In the best case, your car will run a little hotter, maybe blow a little smoke. In the worst case, your bearings will seize, the engine will stop, and you will need to walk back to the pits.

To avoid this, there are a few options: 1) Fit a good dry sump. 2) Fit an oil accumulator. 3) Try baffling your wet sump, and improving the pickup position/arrangement. 4) Try running a little extra oil in your wet sump (this is not ideal as you will get windage). 5) Bring plenty of spare engines.

6. Flat Battery

Most cars refuse to start when the battery is flat. A bump or jump start may be an option, but is not ideal.

To avoid this, always charge your battery between race meetings. Always turn your battery and accessories off between sessions. If you can, carry a spare, charged battery in your spares kit.

7. Something Left in the Boot

Never happens. Yeah right. It may be something that was in the boot for the trip to the circuit. It may be a tool, or some leftover parts. It may actually be in the cockpit. Either way, it's a hazard. It can damage oil, fuel or hydraulic lines. It can damage the driver. If it's really heavy, it can upset the centre of gravity.

To avoid this, check your whole vehicle for loose articles before every session. Add it to your pre-session checklist!

8. Soft Brake Pedal

This can manifest in two different ways: as soon as you drive out of the pits, or once you start hammering the car.

If it's as you drive out of the pits, it's usually because the brakes haven't been bled, and there is air in the system. Bleed your brakes.

If it is when you are hammering the car, it can be quite off putting. The brakes work, but the pedal never ends up in the same spot (this can make heel-toe difficult). There are a few things that can cause this - very hot brake fluid, very hot pads, pad knock-off (either due to warps in the disc, or if the hub is moving relative to the caliper over kerbs or similar). The best way to avoid it is to tap the brake pedal (softly, not enough to slow the car) on the straight. This will reset the pedal position, and should give you a firm pedal in the braking zone.

9. Steering Wheel Off Centre

Having the steering wheel off centre is not the end of the world, but it can be a little off putting to the driver. There are usually two scenarios when it can happen. 1) The steering wheel is on a quick release hub, and is aligned incorrectly when fitted (or the 'slow release' splines are incorrectly aligned when the steering wheel is installed). 2) The wheel alignment is completed with the steering wheel off centre.

To avoid this: 1) Clearly mark the splines and the hub so the wheel can be installed on the same position every time. 2) Put a small strip on the very centre of the top of the steering wheel, align this with part of the cockpit/dash, and lock the wheel in place when doing a wheel alignment.

10. Left Something Important at Home

Sometimes it's your racing licence, or your helmet. Sometimes it's a crucial tool, or a part of the car that you really need. Either way it's a large inconvenience, and could preclude you from competing at that meeting.

To avoid this, create a packlist. List everything you need to take to every race meeting (or at least the mission critical items). If you like, you can laminate it and tick things off each time you pack.

So, there you go. Plenty of things to think about avoiding the next time you go racing. You may have noticed that a "pre-session checklist" featured a number of times. It's a very simple way to ensure that very simple mistakes don't happen to you. Perhaps your New Years Resolution could be to make (and use) a pre-session checklist...

Happy New Year!

Do you have something to add to this list? Head over to the iRace Facebook page and share your thoughts with everyone.

Crash Proofing

What is the cause of most aviation accidents:
Usually it is because someone does too much too soon, followed very quickly by too little too late.
— Steve Wilson, NTSB investigator


It's something we don't like to think about too much. Crashing. But sometimes it happens. Mechanical failure, driver error, attempting to avoid someone elses error, pushing that little bit too hard - there are plenty of things that can lead to a crash, and once the trigger has happened, it's too late to be worrying about whether all the right protections are in place. They need to be complete before the car ever turns a wheel in anger.

So, in this article we're not going to be looking at what you can do to avoid having a crash (the doing "too much too soon" from the quote at the top), rather we'll look at what you can do to your racecar in advance to ensure that if you ever do end up in that situation you're not left with the second part of the quote: "too little too late".

It's not possible to make your car "crash proof", but it is possible to apply the maximum amount of thought, effort and preparation to provide yourself the maximum chance of survival, and minimum chance of injury.


The aviation world are the accepted experts when it comes to crashworthiness. And they define crashworthiness as follows:

The ability of an aircraft and its internal systems to protect occupants from injury in the event of a crash.

Substitute the word aircraft for racecar, and this sounds a lot like something we might want to achieve.


So, what are the principles and how do they apply to us?

The aviation industry uses an acronym to describe the specific areas for attention when assessing/improving crashworthiness. The acronym is CREEP.

C - Container
R - Restraint
E - Energy absorption
E - Environment (local)
P - Postcrash factors

That's great, but how do these apply to us?


The container in an aircraft is the cockpit and cabin area - the space where people go. For us, it's the cockpit, or passenger cell.

Ideally the container will form a protective shell around the occupant(s) in the event of a crash. It should be strong, and protect as many sides as possible. The container needs to protect the occupant from external objects penetrating the skin, and also from other parts of the vehicle entering the cabin.

To improve the integrity of the container, racecars are often seam welded, strengthening panels may be added to parts of the skin. The rollcage is a very important feature of our container. Other things you can do is race with your windows up, and fit and use window nets. Some racecars feature side impact protection, in the form of carbon fibre slabs mounted to the side of the driver.


Obviously restraint refers to any system or device which keeps the occupant(s) in position. This is desirable to avoid the occupant contacting parts of the inside of the container, or being ejected altogether.

In a racecar, the restraint must be strong. The stronger and wider the webbing of your multi-point harness, the more chance the harness has of keeping you in place. One sometimes overlooked part of the restraint is its mounting - the mounts must be strong, and not allow the restraint to come loose under impact conditions.

The basic lap-strap stops the midsection from moving forward. Shoulder straps stop the upper body from moving forward (or to the side), and crotch straps reduce the chance of 'submarining'.

A HANS device can be considered as an addition to the restraint system, and stops the head and neck being overextended, and greatly reduces the likelihood of neck injuries.

Window nets are another aspect of restraint (and crossover to the container section). Some cars also feature small straps connected to the arms to minimise the chance of flailing (sometimes seen in use in Sprintcars).

Energy Absorption

This refers to the ability of the vehicle to absorb some of the impact energy to reduce the impact loading on the occupant. The more absorption, the more time is available for deceleration, and the less force is applied to the occupant.

This can be seen vividly in the video above. The 'crumple-zones' of the late model car provide more time for the deceleration to occur, and the forces on the occupant are greatly reduced.

In our racecar, there is not a lot that can be done to improve energy absorption, it is inherited from the vehicle manufacturer. We can ensure that our car is correctly assembled and that all parts are in good repair (no rust!).

Local Environment

This means the area in the cabin around the occupants. Obviously you would not install sharp knives pointing at the driver so in an impact he has nowhere to go but to the knives.

Crashworthiness looks at all objects within reach of the occupant in a crash scenario - with restraints at full extension, and extremities (arms and legs) flailing. Sharp edges, switches, steering wheels are some common local environment hazards.

Have a good look at the cockpit of your car, and see if there is anything you would be happy to slam your hand against at full force, anywhere in reach of your arms, legs and head. If you find something, look at if it may be able to be relocated or 'de-lethalized' - put a foam cover over it, or otherwise reduce the consequence of an impact.

Postcrash Factors

This is what happens to the vehicle in the aftermath of a crash. Does fuel keep pumping through the fuel lines? Do the petrol/oil/lubricant tanks rupture and leak? Common postcrash hazards are: fire, fumes, fuel, oil and water.

The ideal scenario is to control these hazards at their source. In a racecar, a crash resistant fuel cell is much less likely to allow fuel out to start a fire. An automatic fuel pump cutoff will stop pumping fuel to the hot engine bay. A manual isolation switch will stop everything (if someone is able to activate it). Second best is dealing with the subsequent problem: extinguishing the fire, wearing flameproof nomex clothing etc.

There are many things we can do to help with postcrash factors including: fitting the best systems - fuel cell, fuel pump cutoff, leakproof catch tanks and reservoirs; wearing the best safety gear - nomex overalls and underwear; providing first aid equipment - serviceable fire extinguisher and manual cutoff switch.

The final part of postcrash factors is getting safely out of the vehicle. The restraint system must be easily released, and the doors must be easy to open and egress through. You should regularly familiarise yourself with escaping your racecar - try to imagine it is on fire, close your eyes, and practice getting out. It may save your life.


So, hopefully we never need to use this stuff. But, if we ever do, time spent thinking about, and addressing it now, may be enough to save your life, and you won't be relying on 'too little too late'.

Biased Opinion

Racing is about getting the maximum speed out of the car to achieve the minimum laptime. In circuit racing, we go around corners, and to ensure we can go as fast as possible for as long as possible, and still negotiate the next corner, braking is critical.

To achieve optimum braking, we need to apply the right amount of braking force through each of our tyres. Too much force and the tyre will lock, reducing braking efficiency, too little force and we will either not make the corner, or need to commence braking too early. This situation is complicated further by the transfer of weight as the braking force is applied, giving our front tyres more grip than the rear tyres, and offering more braking potential through the front tyres than the rears.

Most race cars will feature some method of brake bias adjustment to vary the ratio between front and rear braking force (some very advanced setups, previously seen in F1, dynamically varied the force side-to-side aswell, but that is well beyond the scope of this article!). This article will outline two methods of adjusting brake bias to achieve that optimum ratio.

The goal is always when braking at maximum capacity that an increase in braking force will cause the front and rear tyres to lock simultaneously.

There are two main types of bias adjustment. The most common, and preferred method is to adjust a balance bar within the pivot of the brake pedal, varying the ratio of force between the front and rear brake master cylinders.


A small knob is usually mounted on the dashboard. Rotating the knob rotates the cable, which in turn rotates the threaded rod. As the threaded rod rotates, the pivot point moves toward the front or rear master cylinder, varying the proportion of force applied.

The alternative system, which offers a slightly more coarse adjustment (and is somewhat more prone to hysteresis and unreliability) is the proportioning valve. Usually mounted in the rear brake line, the valve limits the flow of fluid between the rear master cylinder and the rear brakes, effectively adjusting the ratio of front to rear force by reducing the force at the rear.


There are two main variants - the lever type, which offers fast, coarse adjustment, and the knob type, which offers slower, more fine adjustment.

There are two techniques to setting the brake bias. Both can be used with either of the systems outlined above.

Method #1
The first method can be done in the workshop, before even arriving at the circuit. This is a 'ballpark' type setting, and should usually be refined by using the second method on-track. If done correctly though, the initial setting will usually be within a turn or so of the ideal setting.

Fit wheels and tyres to the racecar, ensure the brakes are free of oil, corrosion or any other friction reducing problems. Place the car on stands and have a helper in the driver's seat. The helper must be reliable and able to maintain a set brake pedal pressure.

Position yourself so you can rotate the front wheels by hand. Start rotating the wheel (slowly is fine) by hand, and have the helper slowly press the brake pedal. Once your helper reaches a pedal pressure where you can no longer rotate the front wheels, have him/her hold that pedal pressure. Move to the rear wheels and attempt to rotate by hand. If the bias is set correctly, you should just barely be able to rotate the rear wheels.

If you can rotate the rear wheels freely, adjust the bias towards the rear and repeat the test. If you are unable to rotate the rear wheels, adjust the bias towards the front and repeat the test. Continue repeating until you can just barely rotate the rear wheels when the front wheels are locked.

Method #2
This method is more accurate, but requires excellent driver feel, and preferably an outside observer. It also requires a racetrack or other safe operating area.

Warm the car up, and drive at moderate pace toward the test (braking) area. Apply the brakes normally, until either the front or rear wheels are felt to lock. Use the feedback of the outside observer to confirm which wheels locked (if all four locked, you need to repeat the test, or you bias may already be perfect). Adjust the bias away from the end that locked. Repeat the test. Repeat until under normal braking, as force is increased, all four wheels lock at the same time. It is important to note that 'panic' or unusually rapid braking is of no benefit for this test, as the car needs to be in a normal braking state (stabilised with weight transfer at or near where it will be under normal, race braking).

Other Notes:
Further fine tuning should be done under practice/race conditions. It can sometimes be beneficial to have a slight bias to one end or the other, for example and understeering car may respond well to a slightly more rearward bias, effectively overloading the rear tyres and allowing some rotation of the car on the brakes to compensate for the lack of front grip ('backing it in'). A slight bias towards the front is a more stable, and beginner driver friendly state, as it gives more warning that the limit is being reached.

Further Reading:
Read Carroll Smith's books. Tune to Win and Drive to Win are probably most relevant to this topic, but all of his books are invaluable.

Remember, you are responsible for the consequences of any changes you make, and any adverse outcomes. This article is provided for reference only. Neither iRace or the author offer any warranty or any liability for any damage or injury caused by tweaking any racecar.

Pyro Maniac

Motorsport is all about tyres. Driving a racecar is all about getting the most out of the tyres, and racecar setup concentrates on making sure the tyres deliver maximum grip. As most racers know, the right suspension settings are vital to ensuring the racecar performs at full potential.

But for a car that doesn't come with a specification sheet outlining the optimum settings, how do we figure out what settings to use? Many racers will go with their gut feeling, or perhaps use settings that have worked on a previous car, or they may be able to copy the settings from a similar car. These are all workable methods, but there is a more scientific method to establish the ideal settings. The method involves the use of a tyre pyrometer, and a rough outline of the technique will be the subject of this article.

Spring rates, shock absorber settings and baseline suspension geometry will not be covered in this article. Baseline geometry is usually determined at the vehicle design stage, and may be limited by packaging and construction issues. Ideal spring rates will vary depending on sprung weight, vehicle corner weight, the bump frequency of circuits visited and finally the front-rear balance desired. Shock absorber settings are a specialised area beyond the scope of this article. More information on these topics is available in Allan Staniforth's excellent book: Competition Car Suspension.

This article will look at how we can use a tyre pyrometer to determine the optimum wheel alignment settings (camber, toe, caster) and optimum tyre pressures.

Equipment Required

50635.jpgA basic probe-type pyrometer is the best kind. There are infrared pyrometers available, but they measure the surface temperature, not the core temperature that we're actually looking for. A decent probe-type pyrometer should cost around $200. There are some available here and here. Make sure you carry spare batteries with you too.

You'll also need a good tyre gauge, plus a pencil and a notepad.

There is some excellent software available from Paul Van Valkenburgh don't be put off by the basic website, the software is very good, and runs on a very basic Palm PDA (available for around $50 from Cash Converters). This software is not a requirement, but can prove to be a timesaver when using the techniques described in this article.

Background Concepts

Tyre temperatures give a very good indication of how the tyres are working. Every tyre has an optimum working temperature, where it will deliver maximum grip for the maximum length of time. If a tyre is overworked, it will generally run hotter, it may deliver a little more grip for a short period, but will quickly deteriorate. If a tyre is underworked, it will run cooler. Comparing the temperature of the front tyres to the rears will give an indication of balance, the hotter end is working harder than the cooler end (the driver's feedback should confirm this). We can also get an idea of how well each individual tyre is working by comparing temperatures across the face of the tyre. We look at the temperature near the outside edge of the tread, the centre and near the inside edge. Comparing these temperatures will give us an idea of if our tyre is contacting the circuit in an optimal way - if part of the tyre is too cool, it may not be contacting the bitumen correctly; if part is too hot, it may be taking more than it's fair share of the load.

Measuring Tyre Temperatures

tyre.001.pngWhat we're after is a picture of how the tyres are working, by measuring their operating temperature. Ideally, we would take this picture at the exact moment the tyres are working their hardest - in the middle of a corner. This is not practical without a very expensive onboard infrared sensor setup (like Formula 1 teams will use during testing), so we're faced with taking the temperatures in the pits. To give ourselves the best picture, we need the tyres to work hard for at least a few laps, and for that work to be sustained for as long as possible before stopping (push the car hard right up until pit entry). Enter the pits safely, and then ensure minimum delay before taking the temperatures (a crew member or two dedicated to taking the temps as soon as the car pulls up is a good idea).

Photo on 2009-10-25 at 18.14.jpgTake temperatures and pressures on each tyre. To take the temperature the probe should be inserted a millimetre or two into the tread of the tyre in three places across the tread - about 30mm from the outside edge of the working tread (tread that is working on the bitumen will have a 'rough' appearance), in the centre of the tread, and about 30mm from the inside edge of the working tread. Record all figures in a notebook (a sample recording may look something like the note on the right). Work quickly but carefully to ensure the data obtained is as accurate as possible (and so there is minimum cooling time between the readings for each tyre). You should also note on the same page the starting cold tyre pressure from before the car ran on the circuit.

Interpreting Tyre Temperatures

The ideal temperature for any tyre should be available from the tyre supplier or manufacturer (if you obtain this figure, make sure you measure your temps in the same scale - celsius or fahrenheit). If the temperature is not available, you should be able to get a good idea from other competitors, or from comparing your own recorded temperatures with how the car performed or felt. Once you have a target temperature, you can compare your recorded temps.

For our example, we'll assume an optimum of 140 degrees fahrenheit, and 21psi hot pressure.

Recorded temps were as follows:
LF OCI: 120/125/130 RF ICO: 140/135/120
LR OCI: 145/160/145 RR ICO: 145/150/145

To get an average, add up all the temps for the factor you're considering and divide by the number of temps you've added (eg; for front to rear bias, add all the front temps, then divide by 6, add all the rear temps, divide by 6, then you can compare the average front temp with the average rear temp).


From our example we can immediately see that the rear tyres are overall hotter than the front. This car is using it's rear tyres more than it's fronts. It's likely that the car has an overall oversteer balance. This may be influenced by the driver's style (he may be balancing the car on the throttle and/or driving around understeer by provoking oversteer), and could be clarified by the driver's comments. There isn't a massive front-rear differential, so it appears that the overall balance is reasonably close to optimum. (F 128 : R 148 = 20 degrees differential) More than 20 degrees differential may warrant further investigation.


Looking at the diagonal temperatures, we can see that the LEFT REAR and RIGHT FRONT are the hottest tyres at their respective ends. This could indicate a corner weight issue - generally if the corner weights are out, diagonal temps will be effected. In this case it could be that there is not enough weight on the left front and/or right rear. As for the overall balance, the differential is not very large (LF/RR average= 136, LR/RF average= 141). A differential of more than 20 degrees may be worthy of investigation of the corner weights.

CAMBER (Static)

Looking at the across tread temperatures for each tyre will give an idea on which part of the tyre is working hardest. To assess camber, we need to look at each tyre individually. We need to have an idea of the existing camber settings because on a tyre where there is a lot of negative camber, the outside edge can cool a little on the run into the pits.
LF: We know this tyre has about 2.5 degrees of negative camber. The temps across the tread look about right - around 5 degrees cooling between the inside and the centre, and another 5 to the outside, is about normal. Camber setting of this wheel is correct.
RF: This tyre has a 20 degree difference between the inside and the outside. The inside is working quite a bit harder than the outside. This tyre should have the negative camber reduced (tyre stood up more vertical). A rough ballpark in this case may be a 0.5 degree change.
LR: The temps on the inside and outside are the same - camber setting of this wheel is correct.
RR: Camber setting is correct.


The highest temperature across the tread will indicate the part of the tyre that is working hardest. If the outside edges are hotter, the pressure is probably too low. If the centre is hotter, the pressure is probably too high. Again, we need to look at each tyre individually.
LF: The average edge temperature (add outside and inside temp and divide by 2) is equal to the centre temp. The tyre pressure is optimum.
RF: Edge average is 5 degrees cooler than the centre. This indicates a pressure that is slightly too high. Consider reducing pressure by 0.5 or 1 psi (subsequent pyrometer readings may be used to fine tune).
LR: This tyre has a much higher centre temp than average edge temp - a fifteen degree differential. This tyre is overinflated. Reduce pressure by 1 to 2 psi.
RR: A little hot in the centre, but this tyre is not far from optimum. Consider reducing pressure by 0.5 psi.


There are other factors to consider when setting the toe. Toe out makes that end of the car less stable (this sounds bad, but can be a good thing, when you consider that being less stable can mean that end of the car will bite into, or steer more positively). Toe in makes that end more stable, but may reduce responsiveness. Any kind of toe either side of zero (wheels perfectly parallel) will generate scrub on the tyres (as they rotate against the bitumen, they are pulling a little in the direction of the toe, but can't move in that direction as the wheels remain connected to the car). This scrub causes tyre wear, but also helps to keep the tyres at operating temperature on the straights (ready to do their job at the next corner). In our example above, we may consider increasing the toe out - this will help with the steering of the car (the car will want to point into the corners) and also help to increase the average front tyre temps. We need to be very careful about this though - the added 'pointiness' may actually translate to more oversteer on corner entry.


A race car will generally run as much caster as possible, at least on the front suspension. If not, and there is scope for caster adjustment, it should be remembered that caster will contribute to dynamic camber. That is, when steering lock is applied, a car with high caster on the front will increase the amount of dynamic negative camber (the loaded outside wheel will effectively lean into the corner as steering is added). Thing start to get very complicated, but a very high caster setting may be the reason the inside edge of the tyre tread runs very hot.

Final Word

Measuring the temperature of the tread of your tyres can give you a lot of information about how well the car is working. It can give you a good starting point for what changes might need to be made. Ultimately though, driver feedback is vital. An apprarent anomaly in the readings may be easily explained by the driver.

If you are going to make changes, record everything, including your reasoning for the change (and what the original settings were). This way, if you get confused, you can reset back to where you started.

And remember, you are responsible for the consequences of any changes you make, and any adverse outcomes. This article is provided for reference only. Neither iRace or the author offer any warranty or any liability for any damage or injury caused by tweaking any racecar.

Further Reading

Drive to Win - Carroll Smith
Tune to Win - Carroll Smith
Competition Car Suspension - Allan Staniforth

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