At the most basic level:

Transcription

1 At the most basic level: Each road course turn can be dissected into an entry, middle, and an exit. Dissecting a corner into those elements and analyzing the cars performance is the key to going faster. Don t confuse going fast with scaring the bejesus out of yourself at every corner, either. As road course racers quickly find out, a smooth, steady, calculated, fast pace throughout the entire course results in better lap times. The abusive treatment of throttle and brakes just wear out the car faster. When setting up a road course chassis, the goal is to achieve the most traction where it will benefit lap times and passing the most. That means compromise. Since a car can only have one setup and a road course typically has many turns, the approach to chassis setup should revolve around the most important corner. But what is the most important corner, anyway? According to some, it is often the one that leads to the longest straightaway with the best passing opportunity. Of course, setting up a car for the most important corner doesn t mean ignoring the rest of the track, either. It s a compromise between having a setup that behaves as well as possible throughout the whole of the course, but places emphasis on making the car perform where it s realistically possible to make gains. With this approach you will be extremely fast in a few corners, good in a few more, and taking it easy in the bad corners. Rules of Thumb 1. If the car is tight overall, try using a softer front sway bar, stiffer rear springs, raising the track bar, using softer front springs, or a combination of them all. 2. If the car is loose going into the corner, use a stiffer front sway bar, a softer rear sway bar; lower the track bar, or a combination of these solutions. If the car is loose exiting the corner, use a stiffer front sway bar, softer rear springs, or a combination of the two. Camber, Caster, and Toe From a handling stand point, camber, caster, and toe affect the perceived balance of the car (and the actual performance). As you probably already know, camber describes the inward or outward tilt of the wheels. When wheels tilt inward at the top, they have negative camber. When wheels tilt outward at the top, they have positive camber. The front wheels on most race cars have

2 negative camber, but not always at a symmetrical angle. Camber also depends on a cars particular type of suspension design and the track, so generalities are few. The goal for tuning with camber is to maximize the contact patch of the tire in relation to the changing geometry of the suspension when the car is cornering. Caster describes the angle that the front wheels create when turned. Although people disagree about the effects of caster as a good thing, positive caster adds desirable cross weight when turning into a corner. When the car is on a set of scales, turn the wheels to the right and left to see how the diagonal cross weight changes on cars with a lot of positive caster. On a Southwest Tour car at Sears Point, for example, run about four degrees negative camber on the left, three degrees negative camber on the right, and about five degrees positive caster on both wheels. Unfortunately, there is no such thing as perfect camber on a road course. A gain in one turn can cause a loss in a different turn. The best approach is to analyze the race track and have good driver feedback. Also monitor tire temps on the outside, middle, and inside; and inspect tires closely for uneven wear. However, tire temperatures should not always be considered gospel, because they may not be representative of the entire course and can change by the time the car gets in the pits and is parked. Toe-in and toe-out describe the front wheels inclination to be pointed slightly toward each other or slightly away. Toe-in occurs when the front of the tires point in toward each other; toe-out occurs when the front of the wheels point away from the car. Street cars with front-wheel-drive typically are set with toe-out because the wheels tend to pull toward each other under acceleration. Understanding the Vehicle Understeer: This is when, at the limit of vehicle traction, the front of the car slides first before the rear. Race car drivers call this "push". This is the way that many cars come set up to behave from the factory as it is the most predictable for average drivers. The crash mode for understeer is that when the limit of adhesion is exceeded, the car will plow straight ahead off the road nose first. When the car understeers you should regain control if you let off the gas, unless of course you run out of road first. It is not efficient for extracting maximum lateral G s because the car will dynamically use the front tires excessively for turning, overloading them while the rear tires basically just hold the back of the car up. Front wheel drive cars like ours tend to exhibit understeer as the final terminal mode of balance.

3 Oversteer: This is when, at the limit of vehicle traction, the rear of the car slides first before the front. Race car drivers call this "loose". The final crash mode of oversteer is backwards, tail first into the woods or in the worst case spinning round and round with the driver as a helpless passenger. Although oversteer looks neat and macho it is really a slow way to drive except in pro-rally on the dirt which I don t know too much about. Oversteer is slow on the pavement because hanging the tail out bleeds off a great deal of speed going through a corner. Conserving the momentum is the fast way around as turn. Neutral: This is the fast way around a turn where all four wheels slide evenly. Since the total friction circle traction of each tire is being used, all the available grip that the tires have is being put to the ground. Racers call this "drifting". This not to be mistaken for the idiotic Japanese Option Magazine video stuff which makes a mockery of proper driving technique. Neutral is the fast way around a corner most of the time. Neutral is also the hardest handling mode to achieve for the suspension tuner. Polar Moment of Inertia: Or PMI as we will refer to it, is a description of how a cars mass is distributed along the length of the vehicle. A car with a high PMI is like a rear engine, rear drive car like a Porsche 911 or a front engine, front wheel drive car, same thing only the poles are different, so to speak. A car with a low PMI would be a mid engine car like a Boxster. Low PMI cars have most of their mass about the middle, high PMI cars have the mass at one end or another. Low PMI cars are the easiest to get a neutral balance out of due to the balanced, centralized mass. High PMI cars like to oversteer, in the case of the 911 or understeer like our cars. Slip Angle: This is the wonderful thing that allows us to tune our cars suspensions despite the design limitations caused by the PMI. Proper manipulation of slip angle is the great equalizer and is what suspension tuning is all about. Slip angle is the difference in which a cars wheels are pointed vs. the angle that the tires contact patch is placed on the road. The main thing that affects slip angle is the manipulation of the individual load placed on each wheel while cornering. This is the key for suspension tuning. A front wheel drive car has most of the weight on the front wheels. So the front wheels run at higher slip angles and develop understeer. Conversely the same for a rear wheel drive, rear engine car developing oversteer. That is also a reason why a mid engine car with equally loaded tires will be more or less neutral. Slip angles, weight distribution

4 and PMI are the main factors in how a vehicle will handle. Because our cars are front heavy, front tire overloaded, front wheel drive cars, does that mean that we are condemned? Heck no! By design we cannot change the basic layout of our cars to significantly change the PMI or weight distribution but we can sure tweak the slip angles of the tires to achieve world class handling out of our killer econo transportation units. The easy way to tweak the slip angles are with anti-sway bars and springs. Shock absorbers, going against what people think that they do, are not really for changing the handling balance. Shocks mostly act as spring dampers and affect understeer/oversteer balance mostly only in transient (which is big word for a change from straight line travel to turning) maneuvers like initial turn-in and zig zagging around slalom cones. Changing to heavier springs changes the slip angle differential by resisting the cars tendency to roll on the end of the car that they are installed on. The resistance of the heavier spring to compression causes more weight to be transferred to the outside wheel of the end of the car that they are installed on as the car tries to lean over in a corner. This causes that wheel to proportionally run at a higher slip angle than it normally would. If you put heavier than stock springs in the rear,while not changing the spring rate of the front, the car would tend to understeer less. Antisway bars work in much the same way. Sway bars are torsion bars attached to the cars chassis and are linked to the right and left control arms. Sway bars offer resistance to independent side to side wheel movement. This is how these bars limit sway in the turns and hence their name. While limiting sway, the sway bars also cause weight transfer to the outside wheels. By altering the diameter of the sway bars or installing them where there were none before adds yet another chassis tuning element. If you were to increase the size of the rear sway bar you would be increasing the amount of weight transfer to the outside rear wheel, thus causing it to run a bigger slip angle. This would give you more oversteer. Tire pressure also can affect the slip angle. Higher pressures reduce the slip angle and lower pressures increase it. A great deal of suspension tuning can be done for free by adjusting the tires pressure. Alignment also has a great deal of effect on a vehicles handling balance. Caster

5 and camber affect how a tires contact patch is positioned on the ground by compensating for a tires tendency to flex and lift the inside tread while cornering, by helping keep the tread flat, these settings can increase or decrease the available friction circle traction on an end of a car thus affecting balance. Toe in or out can affect balance also by changing how a vehicle turns in. Here is a rough and general matrix on how different parts and adjustments of the suspension and how the adjustments can affect your cars balance Suspension adjustment Affect on vehicle balance, extreme useable adjustment limit Symptom of TOO MUCH adjustment Front spring rate increase More understeer Terminal understeer, front of car hops in corners, excess wheel spin in FWD car Front spring rate decrease Rear spring rate increase. Rear spring rate decrease Less understeer More oversteer Less oversteer Too much oversteer, oversteer then understeer if spring is so soft that the car bottoms under lean, car bottom excessively with a jolting ride Too much oversteer, hop in corners, twitchy Car understeers, if way to soft car understeers then oversteers as car bottoms out under lean, car bottoms out excessively with a jolting ride

6 Front antisway bar stiffer More understeer Terminal understeer, Lifts inside front tire off the ground which can cause massive wheelspin, also not good for most effective tire usage as inside wheel is now doing nothing Front antisway bar softer Less understeer Oversteer Rear antisway bar stiffer More oversteer Big time oversteer, Can cause the inside rear tie to lift off the ground which is not two bad on a FWD car. On Classics, if this happens while trail braking into a turn, the abs can shut the brakes down which can be a bit scary Rear antisway bar softer Less oversteer understeer Front tire pressure higher Less understeer Except with BFG R-1 tires. They will grip less and understeer more if the pressures are increased within a reasonable amount. No traction as tire is crowned so more understeer, bad wheel spin, jarring ride, center of tires wears out Front tire pressure lower More understeer Except with BFG R-1 tires. They will grip more and understeer less if the pressures are decreased within a reasonable amount. Edges of tires wear quickly because tire is folding over, feels mushy, tires chunk because low pressure means more heat build up

7 Rear tire pressures higher Rear tire pressures lower More negative camber on front wheels Positive camber on front wheels More negative camber on rear wheels More positive camber at rear Less oversteer Except with BFG R-1 tires. They will grip less and oversteer more if the pressures are increased within a reasonable amount. More oversteer Except with BFG R-1 tires. They will grip more and oversteer less if the pressures are decreased within a reasonable amount. Less understeer/ -3 degrees More understeer, a little can make the tires last a little longer Less oversteer, more rear grip, less breakaway warning when limit is exceeded/-3 degrees More oversteer, more forgiving at limit No traction as tire is crowned so more oversteer, bad wheel spin on RWD cars, jarring ride, center of tire wears out Edges of tires wear quickly because tire is folding over and cupping upward, feels loose in back, tires chunk because low pressure means more heat build up Poor braking, car is road crown sensitive, twitchy, tires wear out on the inside edge Poor braking, car is road crown sensitive, twitchy, tires wear out on the outside edge You almost never want to have positive camber unless you are a dweeb More oversteer, car feels twitchy in back, tires wear out on inside edge Car feels twitchy in the back, tires wear out on outside edge

8 Ride height to low, rice boy style Toe-in front Toe-in rear Toe-out front Toe-out rear Car twitchy with unpredictable dynamics, don t race on when you see it because they will crash, taking you out Car is stable while going straight. Turn in is average/1/8 inch total toe-in car is less likely to suddenly oversteer when throttle is lifted/1/8 inch total toe-in Car turns in well, works pretty good in FWD cars as they tend to toe-in under load/1/4 inch total toe out Helps the car rotate, useful on tight low speed courses and slalom events/1/8 inch total toe out Everything that could possibly be wrong, sudden over or understeer, twitchy due to bumpsteer Car has slow twitchiness under braking, feels odd, kills the outside edge of tires Weird slow rocking movement in back, feels slow but still unstable, wears the outside edge of tires Car is real twitchy under braking, car is very road crown sensitive, car wanders on straight road, kills inside edge of tires. Not to good for street driving, causes lift throttle oversteer, car makes violent side to side rocking motions in rear, tires wear more on insides

9 Positive front caster Helps both stability, steady state cornering and turn in because the suspension will get more negative camber when the wheel is turned/ 6-7 degrees positive, negative caster is not useable Can increase understeer, especially in cars with wide, low profile tires due to a non linear increase in corner weight. Increases steering effort, SE-R s are not easily modified to make this adjustable, FWD cars can see an increase of torque steer with excessive positive caster Here are some general basic rules if you want to improve your cars handling: Do not lower your car too much! This perhaps is the number one no no. Lowering looks really cool and can make a significant improvement to a cars cornering capability but going too low is detrimental to both handling and even safety. Going too low can cause bumpsteer, where the tie rods and control arms are traveling different arcs resulting in the wheels steering themselves with no steering wheel input. When a car is so low that the suspension bottoms under cornering loads, the end of the car that bottoms first will violently slide out. Super low guys are convinced that they are driving super touring cars but if you take them out on the track they will suck incredibly. Our cars are cursed with short travel suspension as it is and cannot take being lowered more than inches at the most. So install some good springs, you want to maintain at least 1-3/4" of travel. Buy and install matched components from a single manufacture. For

10 instance do not put H&R front springs in with Eibach rear or a Suspension Techniques front bar with a TMC rear. Suspension manufactures usually offer these parts as a tuned set with rates, etc. made to match each other. So unless you really know what you are doing don t mix and match. If you are using high performance springs, try to wait until you can afford the shocks also. Performance springs store more potential energy when they are compressed. They need a shock with more rebound damping to keep the car from bouncing all over the place after you hit a bump. Really good shocks like Koni or GAB s are adjustable so you can tune your shocks to the springs. Performance springs with stock shocks usually feel floaty on high speed undulations. I find that that feels a little spooky. Performance spring s quicker rebound characteristics also seem to wear out stock shocks quickly making them get super floaty. Limiting body roll is good. Our cars sit high, and have fairly soft springs from the factory. They roll almost as bad as French cars. Install stiff springs and swaybars with matching shocks, and lower the car to a reasonable level. Limiting roll keeps the weight from transferring excessively, allowing the inside tires to work more in a turn. Limiting roll also helps keep the car from bottoming in a turn and keeps the car out of the bumpsteer zone. McPherson strut cars like ours do not gain negative camber under roll either so limiting roll helps keep the tires from folding over. Having adjustably is good. Having the ability to adjust camber and toe is very useful when trying to extract G s from your car. On a showroom stock racer optimizing the alignment and tire pressures alone made the car go from 0.79 to 0.86 g s on the skid pad and 3 seconds a lap faster at Willow Springs. As front camber is not adjustable on our cars it is important to make it so. Stillen and Ground Control make high quality camber plates. These will slightly increase the harshness of your ride but will sharpen turn in due to the elimination of squishy rubber with metal bearings. Rear camber adjustably is not critical on most FWD cars. To make poor boy adjustable camber, you can drill out one of the two strut to spindle bolt holes on the strut housing by about 1/16" This will get you a couple of degrees of camber adjustment. If you are racing Solo II stock class or Showroom stock and don t want to cheat, you can get about degree more negative camber by loosening all of the suspension bolts and having someone hold the wheel in the negative position while you retighten everything.

11 Align your suspension and optimize your tire pressures. In the previous paragraph, I said that alignment and tire pressures can make a huge difference. IT IS TRUE! If you are poor, you can still make big improvements in your cars grip by just playing with tires pressures and the car s alignment. Try the poor boy technique and dial in some front negative camber, increase the front tire pressure, decrease the rear and set your toe. Boy will you see a difference. Try to find a place that does racing alignments near your house as alignment is where people really get ripped off as it is almost never done correctly. Most hacks just throw a car on the rack and if it falls somewhere within in the wide factory specs, don t touch a thing. What you need is a blueprint type alignment where the suspension is adjusted exactly to spec. Most repair shop dorks don t understand this and will argue and tell you that that is not necessary. A race prep shop will understand. When your car is aligned, it should be done with your weight in the driver s seat and with the technician bouncing the car after every adjustment to settle the suspension. Set your tire pressure before you take the car in. Remember that you must realign the car if you lower it! If you are racing, run R compound tires on the widest wheels that will fit. These tires can get more that 2 seconds for every 30 seconds on a slalom course or 3 seconds for every minute on a road course. These tires usually have a vestigial tread and a really short tread life so you don t want to run these as a daily driver tire. Also R type tires only have about 10 good heat cycles in them so their stickiness will decline quickly in daily use, leaving you with a fast wearing, not so sticky tire. Don t over tire or wheel your car. Our cars will go the fastest and handle best with the widest, lightest 15 inch wheel that will fit. A 205/50-15 works well in most cases and a wide variety of R compound tires are available in this size. Tire pressures rise considerably during a run/race. Take notes of your tire pressures before and after every run so you can start with a cold pressure that will increase to your desired hot pressure during a run. Bleed your tire pressure down after every run to keep it cool. Settings:

12 Maybe use a Front Antisway bar (definitely have to test) Set front and rear camber to maximum negative by the loosen, push and retighten method. Set front toe out to 1/8 inch, Set rear toe to Zero or 1/8 out to help car rotate, be careful not to overdo. Start with 40 psi front, 35 rear for tire pressures. These settings will feel yucky on the street and will promote lift throttle oversteer as well as chew up your tires. How to adjust your suspension The information listed above is baseline settings. These work pretty well for my driving style (as well as most of the good drivers that I have worked with) and preferences. Your preference could be different. To find the optimal settings for your personnel suspension set-up there are a few tricks that you can do to make the process less painful and quicker. To adjust your suspension you need a just a few simple things. First you need a good, accurate tire pressure gauge. A gauge with a bleeder valve is very useful. Gauges like this can be gotten at just about any racers supply house for about 20 bucks. Don t waste your money on those expensive electronic gauges. Those are slow to use and never come with bleeder valves. The next bit of stuff to have is a compressed air tank for adjusting tire pressures. Tracks almost never have a handy air tank. I got my tank from Sears for about 50 bucks. Fill it at a gas station or use your home air compressor before heading out. Make sure the tank you buy has a safety relief valve so you don t blow the crap out of yourself if you leave the tank in your hot car during lunch or something. A digital pyrometer is very important. Get one with a wire bead probe. These are used for measuring tire temperature differentials across the tread which is a good tool for judging whether your tires pressures and alignment settings are right. You can get one of these at any racers supply house for 50 to 200 bucks. If you don t want to shell out the bucks for this, bring a bottle of white out with you. A notepad and pen are critical also. With so many adjustment parameters it is important to try to write everything down as you will never remember it all.

13 When at the track, first note your initial settings including the air pressure. Write it all down. Paint a stripe of white out on your tire s sidewalls going down to the tread. It helps if you have someone do all these things for you as it gets pretty hectic when you are trying to get ready to run. Go out and drive the car, making mental notes on how it handles, what you like and what you dislike. When you pit or when your run is over, immediately measure your tire temperatures. You only have a few seconds to do this as the temperatures drop quickly. If the course is clockwise, measure the left side of the car first starting with the left front. If it is counterclockwise, measure the right side first starting on the right front. You want to measure the treads temperature in three places, the outside, the middle and the inside. Push the wire of the bead probe slightly into the rubber for the most accurate measurement. Measure all the tires quickly and be sure to write it all down. Next measure and record the tires pressure quickly before the tires have a chance to cool much. Look at the white out stripe that you made. It is there to indicate if your tires are rolling onto the sidewalls. The stripe should not be worn past the rounded corner of the tread- sidewall junction. Now review your notes and the recorded data. How did you like the way the car handled? Did it push? Was it loose? Was it perfect? Look at your temperature distributions across the tread. Ideally it should be about 10 degrees hotter on the inside than the outside with an even gradient across the tread. This is usually only attainable on a race car with optimized suspension geometry. On a street, production based car that is totally modified for adjustably, even temperatures across the tread may be possible and on a FWD car usually the outside will always be a bit higher. On a stock car you cannot usually get better than a 20 degree gradient. Anyway, the camber and pressures might need some adjustment to get optimal temperature gradients out of the tires. If the temps are fairly even, it means you are using the whole tread of the tire to its fullest. You also want to get the average temps on the front and rear tires the same. That is not possible with a FWD production based car. A spread of degrees is about the best that can be expected with the front tires running hotter than the rears. Modern R compound tires work the best at temperatures above degrees. At temperatures much above 220 degrees, most tires will start to chunk. To know the exact temp that your tire works best, call your tire manufactures tech line for advice. Watch for chunking on the outside edge of the tire, where it is most likely to be a problem with a FWD car. Like I said, play with your air pressures and camber to get the temps right and an even distribution to avoid chunking. Raising the tire pressure will reduce flexing and the tire will run cooler,

14 lowering it will cause the tire to run hotter. Raising the pressure will cause the inside of the tread to run hotter and the edges cooler, lowering will make the outside edges hotter and the inside cooler. Once you are using all of your tires tread properly, you can play with the balance. Look at the previously displayed chart to see all of the variables. Usually you want to play with swaybar and spring rates to balance the car. Toe settings are useful to get the car to turn in and rotate. Keep on monitoring the tire temps and pressures and note how changes affect the car. (BE SURE TO WRITE ALL CHANGES DOWN AND MAKE ONLY ONE CHANGE AT A TIME) In a few sessions you will be able to have a good grip on how to set your car up (bad pun). On a stock car, about the only variables you can play with are tire pressures and toe. Adjust your pressures so the temp gradient is as even as possible across the tread. Since your adjustably is limited this will not be possible. Do not add so much pressure that the outside and middle of the tire is at the same temperature. At this point the tire is crowning with a bulge in the middle. This is not using the tire well. Tire pressures can be used to tune the balance. Try 2 psi increments as most good drivers can feel a difference in that. Remember to only adjust one thing at a time! Toe adjustments are very useful on the stock car also. A little front toe-out can help reduce push and get the car to turn in and set quicker. A little rear toe out can get the rear of a pushing car to rotate in tight turns. If you don t have a pyrometer, then use the white out sidewall stripe method to determine if the tire is rolling over excessively. If you adjust the tire pressure so it is only rolling just to the end of the rounded tread to sidewall juncture, then you are very close to the proper set up. Don t be afraid of adding to much air as I have run up to 55 psi hot on the front tires of heavily understeering Showroom Stock cars with no ill side effects. In fact this is probably safer than allowing the tire to overheat and chunk. Just having the ability to play with the tire pressures at the track can give you a good edge over the typical slalom weekend warrior, at least in the beginner s type classes. As you get better, you will have to master the art of suspension setup to remain competitive

15 Suspension adjustment Affect on vehicle balance, extreme useable adjustment limit Symptom of TOO MUCH adjustment Front spring rate increase More understeer Terminal understeer, front of car hops in corners, excess wheelspin in FWD car Front spring rate decrease Rear spring rate increase. Rear spring rate decrease Less understeer More oversteer Less oversteer Too much oversteer, oversteer then understeer if spring is so soft that the car bottoms under lean, car bottom excessively with a jolting ride Too much oversteer, hop in corners, twitchy Car understeers, if way to soft car understeers then oversteers as car bottoms out under lean, car bottoms out excessively with a jolting ride Front antisway bar stiffer More understeer Terminal understeer, Lifts inside front tire off the ground which can cause massive wheelspin, also not good for most effective tire usage as inside wheel is now doing nothing Front antisway bar softer Less understeer Oversteer

16 Rear antisway bar stiffer More oversteer Big time oversteer, Can cause the inside rear tie to lift off the ground which is not two bad on a FWD car. On Classics, if this happens while trail braking into a turn, the abs can shut the brakes down which can be a bit scary Rear antisway bar softer Less oversteer understeer Front tire pressure higher Less understeer Except with BFG R-1 tires. They will grip less and understeer more if the pressures are increased within a reasonable amount. No traction as tire is crowned so more understeer, bad wheel spin, jarring ride, center of tires wears out Front tire pressure lower Rear tire pressures higher More understeer Except with BFG R-1 tires. They will grip more and understeer less if the pressures are decreased within a reasonable amount. Less oversteer Except with BFG R-1 tires. They will grip less and oversteer more if the pressures are increased within a reasonable amount. Edges of tires wear quickly because tire is folding over, feels mushy, tires chunk because low pressure means more heat build up No traction as tire is crowned so more oversteer, bad wheel spin on RWD cars, jarring ride, center of tire wears out

17 Rear tire pressures lower More negative camber on front wheels Positive camber on front wheels More negative camber on rear wheels More positive camber at rear Ride height to low, rice boy style Toe-in front More oversteer Except with BFG R-1 tires. They will grip more and oversteer less if the pressures are decreased within a reasonable amount. Less understeer/ -3 degrees More understeer, a little can make the tires last a little longer Less oversteer, more rear grip, less breakaway warning when limit is exceeded/-3 degrees More oversteer, more forgiving at limit Car twitchy with unpredictable dynamics, don t race on when you see it because they will crash, taking you out Car is stable while going straight. Turn in is average/1/8 inch total toe-in Edges of tires wear quickly because tire is folding over and cupping upward, feels loose in back, tires chunk because low pressure means more heat build up Poor braking, car is road crown sensitive, twitchy, tires wear out on the inside edge Poor braking, car is road crown sensitive, twitchy, tires wear out on the outside edge You almost never want to have positive camber unless you are a dweeb More oversteer, car feels twitchy in back, tires wear out on inside edge Car feels twichy in the back, tires wear out on outside edge Everything that could possibly be wrong, sudden over or understeer, twichy due to bumpsteer Car has slow twichyness under braking, feels odd, kills the outside edge of tires

18 Toe-in rear Toe-out front Toe-out rear Positive front caster car is less likely to suddenly oversteer when throttle is lifted/1/8 inch total toe-in Car turns in well, works pretty good in FWD cars as they tend to toe-in under load/1/4 inch total toe out Helps the car rotate, useful on tight low speed courses and slalom events/1/8 inch total toe out Helps both stability, steady state cornering and turn in because the suspension will get more negative camber when the wheel is turned/ 6-7 degrees positive, negative caster is not useable Weird slow rocking movement in back, feels slow but still unstable, wears the outside edge of tires Car is real twitchy under braking, car is very road crown sensitive, car wanders on straight road, kills inside edge of tires. Not to good for street driving, causes lift throttle oversteer, car makes violent side to side rocking motions in rear, tires wear more on insides Can increase understeer, especially in cars with wide, low profile tires due to a non linear increase in corner weight. Increases steering effort, SE-R s are not easily modified to make this adjustable, FWD cars can see an increase of torque steer with excessive positive caster