Alignment 001

8/9/2019 Alignment 001

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1500 1st Ave North E112 o Box 90 o Birmingham, AL 35203 o office: (205) 475-2419 oquicktrickalignment.com

negative camber, but not always at a symmetrical angle. Camber also dependson a cars particular type of suspension design and the track, so generalities arefew. The goal for tuning with camber is to maximize the contact patch of the tirein relation to the changing geometry of the suspension when the car is cornering.

Caster describes the angle that the front wheels create when turned. Althoughpeople disagree about the effects of caster as a good thing, positive caster addsdesirable cross weight when turning into a corner. When the car is on a set ofscales, turn the wheels to the right and left to see how the diagonal cross weightchanges on cars with a lot of positive caster.

On a Southwest Tour car at Sears Point, for example, run about four degreesnegative camber on the left, three degrees negative camber on the right, andabout five degrees positive caster on both wheels. Unfortunately, there is nosuch thing as perfect camber on a road course. A gain in one turn can cause aloss in a different turn. The best approach is to analyze the race track and havegood driver feedback. Also monitor tire temps on the outside, middle, and inside;and inspect tires closely for uneven wear. However, tire temperatures should notalways be considered gospel, because they may not be representative of theentire 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 slightlytoward each other or slightly away. Toe-in occurs when the front of the tires pointin toward each other; toe-out occurs when the front of the wheels point awayfrom the car. Street cars with front-wheel-drive typically are set with toe-outbecause 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 carslides first before the rear. Race car drivers call this "push". This is the way thatmany cars come set up to behave from the factory as it is the most predictablefor 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, unlessof course you run out of road first. It is not efficient for extracting maximum lateralGs 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 terminalmode of balance.


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Oversteer: This is when, at the limit of vehicle traction, the rear of the car slidesfirst before the front. Race car drivers call this "loose". The final crash mode ofoversteer is backwards, tail first into the woods or in the worst case spinninground and round with the driver as a helpless passenger. Although oversteerlooks neat and macho it is really a slow way to drive except in pro-rally on the dirtwhich I dont know too much about. Oversteer is slow on the pavement becausehanging 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 availablegrip that the tires have is being put to the ground. Racers call this "drifting". Thisnot to be mistaken for the idiotic Japanese Option Magazine video stuff whichmakes a mockery of proper driving technique. Neutral is the fast way around acorner most of the time. Neutral is also the hardest handling mode to achieve forthe suspension tuner.

Polar Moment of Inertia: Or PMI as we will refer to it, is a description of how acars mass is distributed along the length of the vehicle. A car with a high PMI islike a rear engine, rear drive car like a Porsche 911 or a front engine, front wheeldrive car , same thing only the poles are different, so to speak. A car with a lowPMI would be a mid engine car like a Boxster. Low PMI cars have most of theirmass about the middle, high PMI cars have the mass at one end or another. LowPMI 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 orundersteer like our cars.

Slip Angle: This is the wonderful thing that allows us to tune our carssuspensions despite the design limitations caused by the PMI. Propermanipulation 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. theangle that the tires contact patch is placed on the road. The main thing thataffects slip angle is the manipulation of the individual load placed on each wheelwhile cornering . This is the key for suspension tuning. A front wheel drive car hasmost of the weight on the front wheels. So the front wheels run at higher slipangles and develop understeer. Conversely the same for a rear wheel drive, rearengine car developing oversteer. That is also a reason why a mid engine car withequally loaded tires will be more or less neutral. Slip angles, weight distribution


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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 changethe basic layout of our cars to significantly change the PMI or weight distributionbut we can sure tweak the slip angles of the tires to achieve world class handlingout 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 forchanging the handling balance. Shocks mostly act as spring dampers and affectundersteer/oversteer balance mostly only in transient (which is big word for achange from straight line travel to turning) maneuvers like initial turn-in and zigzagging around slalom cones.

Changing to heavier springs changes the slip angle differential by resisting thecars tendency to roll on the end of the car that they are installed on. Theresistance of the heavier spring to compression causes more weight to betransferred to the outside wheel of the end of the car that they are installed on asthe car tries to lean over in a corner. This causes that wheel to proportionally runat a higher slip angle than it normally would. If you put heavier than stock springsin the rear ,while not changing the spring rate of the front, the car would tend toundersteer less.

Antisway bars work in much the same way . Sway bars are torsion barsattached 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 ishow 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 thediameter of the sway bars or installing them where there were none before addsyet another chassis tuning element. If you were to increase the size of the rearsway 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 moreoversteer.

Tire pressure also can affect the slip angle. Higher pressures reduce the slipangle and lower pressures increase it. A great deal of suspension tuning can bedone for free by adjusting the tires pressure.

Alignment also has a great deal of effect on a vehicles handling balance. Caster


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Front antisway bar stiffer More understeer Terminal understeer, Liftsinside front tire off theground which can causemassive wheelspin , alsonot good for mosteffective tire usage asinside wheel is now doingnothing

Front antisway bar softer Less understeer Oversteer

Rear antisway bar stiffer More oversteer Big time oversteer, Cancause the inside rear tieto lift off the ground whichis not two bad on a FWDcar. On Classics, if thishappens while trailbraking into a turn, theabs can shut the brakesdown which can be a bitscary

Rear antisway bar softer Less oversteer understeer

Front tire pressure higher Less understeerExcept with BFG R-1tires. They will grip lessand understeer more ifthe pressures areincreased within areasonable amount.

No traction as tire iscrowned so moreundersteer, bad wheelspin, jarring ride, centerof tires wears out

Front tire pressure lower More understeerExcept with BFG R-1

tires. They will grip moreand understeer less if thepressures are decreasedwithin a reasonableamount.

Edges of tires wearquickly because tire is

folding over, feels mushy,tires chunk because lowpressure means moreheat build up


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Rear tire pressureshigher

Less oversteerExcept with BFG R-1tires. They will grip lessand oversteer more if thepressures are increasedwithin a reasonableamount.

No traction as tire iscrowned so moreoversteer, bad wheel spinon RWD cars, jarringride, center of tire wearsout

Rear tire pressures lower More oversteerExcept with BFG R-1tires.

They will grip more andoversteer less if thepressures are decreasedwithin a reasonableamount.

Edges of tires wearquickly because tire isfolding over and cupping

upward, feels loose inback, tires chunkbecause low pressuremeans more heat buildup

More negative camber onfront wheels

Less understeer / -3degrees

Poor braking, car is roadcrown sensitive, twitchy,tires wear out on theinside edge

Positive camber on frontwheels

More understeer, a littlecan make the tires last alittle longer

Poor braking, car is roadcrown sensitive, twitchy,tires wear out on theoutside edge You almostnever want to havepositive camber unlessyou are a dweeb

More negative camber onrear wheels

Less oversteer, more reargrip, less breakawaywarning when limit isexceeded /-3 degrees

More oversteer, car feelstwitchy in back, tires wearout on inside edge

More positive camber atrear

More oversteer, moreforgiving at limit

Car feels twitchy in theback, tires wear out onoutside edge


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Ride height to low, riceboy style

Car twitchy withunpredictable dynamics,dont race on when yousee it because they willcrash, taking you out

Everything that couldpossibly be wrong,sudden over orundersteer, twitchy dueto bumpsteer

Toe-in front Car is stable while goingstraight. Turn in isaverage/ 1/8 inch totaltoe-in

Car has slow twitchinessunder braking, feels odd,kills the outside edge oftires

Toe-in rear car is less likely tosuddenly oversteer whenthrottle is lifted/ 1/8 inchtotal toe-in

Weird slow rockingmovement in back, feelsslow but still unstable,wears the outside edgeof tires

Toe-out front Car turns in well, workspretty good in FWD carsas they tend to toe-inunder load /1/4 inch totaltoe out

Car is real twitchy underbraking, car is very roadcrown sensitive, carwanders on straight road,kills inside edge of tires.

Toe-out rear Helps the car rotate,useful on tight low speedcourses and slalomevents/ 1/8 inch total toeout

Not to good for streetdriving, causes lift throttleoversteer, car makesviolent side to siderocking motions in rear,tires wear more oninsides


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Positive front caster Helps both stability,steady state corneringand turn in because thesuspension will get morenegative camber whenthe wheel is turned / 6-7degrees positive,negative caster is notuseable

Can increase understeer,especially in cars withwide, low profile tires dueto a non linear increasein corner weight.Increases steering effort,SE- Rs are not easily modified to make thisadjustable, FWD cars cansee an increase of torquesteer with excessivepositive caster

Here are some general basic rules if you want toimprove 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 carscornering capability but going too low is detrimental to both handling and evensafety. Going too low can cause bumpsteer, where the tie rods and control armsare traveling different arcs resulting in the wheels steering themselves with nosteering 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. Superlow guys are convinced that they are driving super touring cars but if you takethem out on the track they will suck incredibly. Our cars are cursed with shorttravel suspension as it is and cannot take being lowered more than 1.5-2 inchesat the most. So install some good springs, you want to maintain at least 1-3/4" oftravel.

Buy and install matched components from a single manufacture . For


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instance do not put H&R front springs in with Eibach rear or a SuspensionTechniques front bar with a TMC rear. Suspension manufactures usually offerthese parts as a tuned set with rates, etc. made to match each other. So unlessyou really know what you are doing dont mix and match.

If you are using high performance springs, try to wait until you can affordthe shocks also . Performance springs store more potential energy when theyare compressed. They need a shock with more rebound damping to keep the carfrom bouncing all over the place after you hit a bump. Really good shocks likeKoni or GABs are adjustable so you can tune you r shocks to the springs.Performance springs with stock shocks usually feel floaty on high speedundulations. I find that that feels a little spooky. Performance springs quickerrebound characteristics also seem to wear out stock shocks quickly making themget super floaty.

Limiting body roll is good. Our cars sit high, and have fairly soft springs fromthe factory. They roll almost as bad as French cars. Install stiff springs andswaybars with matching shocks, and lower the car to a reasonable level. Limitingroll keeps the weight from transferring excessively, allowing the inside tires towork more in a turn. Limiting roll also helps keep the car from bottoming in a turnand keeps the car out of the bumpsteer zone. McPherson strut cars like ours donot gain negative camber under roll either so limiting roll helps keep the tiresfrom folding over.

Having adjustably is good. Having the ability to adjust camber and toe is veryuseful when trying to extract Gs from your car. On a showroom stock raceroptimizing the alignment and tire pressures alone made the car go from 0.79 to0.86 gs on the skid pad and 3 seconds a lap faster at Willow Springs. As frontcamber is not adjustable on our cars it is important to make it so. Stillen andGround Control make high quality camber plates. These will slightly increase theharshness of your ride but will sharpen turn in due to the elimination of squishyrubber 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 strutto spindle bolt holes on the strut housing by about 1/16" This will get you acouple of degrees of camber adjustment. If you are racing Solo II stock class orShowroom stock and dont want to cheat, you can ge t about degree morenegative camber by loosening all of the suspension bolts and having someonehold the wheel in the negative position while you retighten everything.


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Align your suspension and optimize your tire pressures . In the previousparagraph, 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 carsgrip by just playing with tires pressures and the cars alignment. Try the poor boytechnique and dial in some front negative camber, increase the front tirepressure, decrease the rear and set your toe. Boy will you see a difference. Tryto find a place that does racing alignments near your house as alignment iswhere people really get ripped off as it is almost never done correctly. Mosthacks just throw a car on the rack and if it falls somewhere within in the widefactory specs, dont touch a thing. What you need is a blueprint type alignmentwhere the suspension is adjusted exactly to spec. Most repair shop do rks dontunderstand this and will argue and tell you that that is not necessary. A race prepshop will understand. When your car is aligned, it should be done with yourweight in the drivers seat and with the technician bouncing the car after everyadjustment to settle the suspension. Set your tire pressure before you take thecar 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 slalomcourse or 3 seconds for every minute on a road course. These tires usually havea vestigial tread and a really short tread life so you dont want to run these as adaily driver tire. Also R type tires only have about 10 good heat cycles in them sotheir stickiness will decline quickly in daily use, leaving you with a fast wearing,not so sticky tire.

Dont over tire or wheel your car. Our cars will go the fastest and handle bestwith the widest, lightest 15 inch wheel that will fit. A 205/50-15 works well in mostcases 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 thatwill increase to your desired hot pressure during a run. Bleed your tire pressuredown after every run to keep it cool.

Settings:


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lowering it will cause the tire to run hotter. Raising the pressure will cause theinside of the tread to run hotter and the edges cooler, lowering will make theoutside 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 youwant to play with swaybar and spring rates to balance the car. Toe settings areuseful to get the car to turn in and rotate. Keep on monitoring the tire temps andpressures and note how changes affect the car. (BE SURE TO WRITE ALLCHANGES DOWN AND MAKE ONLY ONE CHANGE AT A TIME) In a fewsessions you will be able to have a good grip on how to set your car up (badpun).On a stock car, about the only variables you can play with are tire pressures andtoe. Adjust your pressures so the temp gradient is as even as possible across thetread. 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 atthe same temperature. At this point the tire is crowning with a bulge in themiddle. This is not using the tire well. Tire pressures can be used to tune thebalance. 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 onthe stock car also. A little front toe-out can help reduce push and get the carto turn in and set quicker. A little rear toe out can get the rear of a pushingcar to rotate in tight turns.If you dont have a pyrometer, then use the white out sidewall str ipe method todetermine if the tire is rolling over excessively. If you adjust the tire pressure so itis only rolling just to the end of the rounded tread to sidewall juncture, then youare very close to the proper set up. Dont be afraid of adding to muc h air as Ihave run up to 55 psi hot on the front tires of heavily understeering ShowroomStock cars with no ill side effects. In fact this is probably safer than allowing thetire to overheat and chunk. Just having the ability to play with the tire pressuresat the track can give you a good edge over the typical slalom weekend warrior, atleast in the beginners type classes. As you get better, you will have to masterthe art of suspension setup to remain competitive


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Suspension adjustment Affect on vehiclebalance, extreme

useable adjus tm entl imi t

Symptom of TOOMUCH adjustment

Front spring rate increase More understeer Terminal understeer,front of car hops incorners, excesswheelspin in FWD car

Front spring rate

decrease

Less understeer Too much oversteer,

oversteer thenundersteer if spring is sosoft that the car bottomsunder lean, car bottomexcessively with a joltingride

Rear spring rateincrease.

More oversteer Too much oversteer, hopin corners, twitchy

Rear spring ratedecrease

Less oversteer Car understeers, if way tosoft car understeers then

oversteers as carbottoms out under lean,car bottoms outexcessively with a joltingride

Front antisway bar stiffer More understeer Terminal understeer, Liftsinside front tire off theground which can causemassive wheelspin, alsonot good for most

effective tire usage asinside wheel is now doingnothing

Front antisway bar softer Less understeer Oversteer


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Rear antisway bar stiffer More oversteer Big time oversteer, Cancause the inside rear tieto lift off the ground whichis not two bad on a FWDcar. On Classics, if thishappens while trailbraking into a turn, theabs can shut the brakesdown which can be a bitscary

Rear antisway bar softer Less oversteer understeerFront tire pressure higher Less understeer

Except with BFG R-1tires. They will grip lessand understeer more ifthe pressures areincreased within areasonable amount.

No traction as tire iscrowned so moreundersteer, bad wheelspin, jarring ride, centerof tires wears out

Front tire pressure lower More understeerExcept with BFG R-1tires. They will grip moreand understeer less if thepressures are decreasedwithin a reasonableamount.

Edges of tires wearquickly because tire isfolding over, feels mushy,tires chunk because lowpressure means moreheat build up

Rear tire pressureshigher

Less oversteerExcept with BFG R-1tires. They will grip lessand oversteer more if thepressures are increased

within a reasonableamount.

No traction as tire iscrowned so moreoversteer, bad wheel spinon RWD cars, jarringride, center of tire wears

out


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Rear tire pressures lower More oversteerExcept with BFG R-1tires.They will grip more andoversteer less if thepressures are decreasedwithin a reasonableamount.

Edges of tires wearquickly because tire isfolding over and cuppingupward, feels loose inback, tires chunkbecause low pressuremeans more heat buildup

More negative camber onfront wheels

Less understeer / -3degrees

Poor braking, car is roadcrown sensitive, twitchy,tires wear out on theinside edge

Positive camber on frontwheels

More understeer, a littlecan make the tires last alittle longer

Poor braking, car is roadcrown sensitive, twitchy,tires wear out on theoutside edge You almostnever want to havepositive camber unlessyou are a dweeb

More negative camber onrear wheels

Less oversteer, more reargrip, less breakawaywarning when limit isexceeded /-3 degrees

More oversteer, car feelstwitchy in back, tires wearout on inside edge

More positive camber atrear

More oversteer, moreforgiving at limit

Car feels twichy in theback, tires wear out onoutside edge

Ride height to low, riceboy style

Car twitchy withunpredictable dynamics,dont race on when yousee it because they willcrash, taking you out

Everything that couldpossibly be wrong,sudden over orundersteer, twichy due tobumpsteer

Toe-in front Car is stable while goingstraight. Turn in isaverage/ 1/8 inch totaltoe-in

Car has slow twichynessunder braking, feels odd,kills the outside edge oftires


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1500 1st Ave North E112 o Box 90 o Birmingham AL 35203 o office: (205) 475 2419 oquicktrickalignment com

Toe-in rear car is less likely tosuddenly oversteer whenthrottle is lifted/ 1/8 inchtotal toe-in

Weird slow rockingmovement in back, feelsslow but still unstable,wears the outside edgeof tires

Toe-out front Car turns in well, workspretty good in FWD carsas they tend to toe-inunder load /1/4 inch totaltoe out

Car is real twitchy underbraking, car is very roadcrown sensitive, carwanders on straight road,kills inside edge of tires.

Toe-out rear Helps the car rotate,useful on tight low speedcourses and slalomevents/ 1/8 inch total toeout

Not to good for streetdriving, causes lift throttleoversteer, car makesviolent side to siderocking motions in rear,tires wear more oninsides

Positive front caster Helps both stability,steady state corneringand turn in because thesuspension will get morenegative camber whenthe wheel is turned / 6-7degrees positive,negative caster is notuseable

Can increase understeer,especially in cars withwide, low profile tires dueto a non linear increasein corner weight.Increases steering effort,SE- Rs are not easilymodified to make thisadjustable, FWD cars cansee an increase of torquesteer with excessivepositive caster

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Alignment 001