Suspension???

[thekrpa]

Hello ljudi moji dragi!

Kako sam covjek, koji nije isao za automehanicara (sto mi je sad zao bajdvej), nisam imao prevelikog kontakta s ovakvim temama te zato znam jako malo o ovom! Želio bih malo više naučiti o ovoj temi, kakve postavke su dobre za drift i zasto i tako to, tako da ne izgledam ko tuntlek kad pricam s automehanicarom koji ce mi pomoc pri slaganju pile u buducnosti!

Ako vam se da pisat uopce o tome, pisite ako ne, nikom nista!

Evo to je to! Hvala na odg! O0

[Tikky]

Ovako, postoji točno ovjes za drift, poput Zaxovog, kod nas se najviše koristi klasičan sportski ovjes, tvrd i nizak, po mogučnosti štelanja visine da camber zadnjih kotača bude ravan ili malo u negativu, prednji se sa "camber plates" dovedu isto negativni položaj da se smanji understeer.
Auto ne treba bit pre tvrd, jer opet nije dobro, to najbolje vidiš i osjetiš kad počneš vozit.

[ciccio-75]

ljepo si reko tikky,auto ne treba biti pretvrd,moj nazalost je pa prije nego ga bacim u drift posne skakutat po cesti sto nije najbolje ali kad je ovjes home made i sa reduciranim budgetom dobar je i takav,i uz to auto mi je prenizak,sto i to nije jako dobro,al sta je tu je
najbolje bi bilo neke gevinde stavit,ali ono sta je dobro to i kosta,koliko para toliko muzike

[chaos]

Kako ide ona uzrečica... 100 ljudi, 100 čudi... e pa tako nešto ti vridi i za aute.
Ako nisi iša za mehaničara (nisan ni ja) valjda koliko toliko kužiš engleski.
Ovo su ti ukratko odgovori ekipe iz natjecanja D1:

Front spring rate increase:
More under steer; increase in proportional weight transfer to the front when rear wheel rate is not increased; reduces front traction when rear rate is not changed.
Usable adjustment: 150-600 lbs/in
Symptoms of too much adjustment: terminal under steer; front of car hops in corners; excessive wheel spin on inside front tire on FF cars.

Front spring rate decrease:
Less under steer; decreases proportional weight transfer to the front when rear wheel rate is not increased; increases front traction when rear rate is not changed.
Usable adjustment: 150-600 lbs/in
Symptoms of to much adjustment: Too much over steer; over steer then under steer if spring is so soft that the car bottoms out on lean, car bottoms out excessively with a jolting ride.

Rear spring rate increase:
More over steer; increase in proportional weight transfer to the rear when front wheel rate is not increased; increases rear traction when front rate is not changed.
Usable range: 100-600 lbs/in
Symptoms of too much adjustment: too much over steer; sidestep hop in corners; twitchy; pretty scary.

Rear spring rate decrease:
Less over steer: decreases proportional weight transfer to the rear when front wheel rate is not changed; increases rear traction when front rate is not changed
Usable range: 100-600 lbs/in
Symptoms of too much adjustment: car under steers; if way to soft car under steers then over steers as car bottoms out on lean; car bottoms out excessively with a jolting ride.

Front anti-roll bar stiffer: more under steer
Usable range: none to 1.25 inches in diameter
Symptoms of to much adjustment: terminal under steer; lifts inside front tire off the ground witch can cause massive wheel spin on FF cars; also not good for most effective tire usage as inside tire is now doing nothing.

Front anti-roll bar softer: less under steer
Usable range: none to 1.25 inches in diameter
Symptoms of to much adjustment: overstate scary; more like fun

Rear anti-roll bar stiffer: more over steer
Usable range: none to 1 inch in diameter
Symptoms of too much adjustment: Big-time over steer. Can cause inside rear tire to lift off the ground.

Rear anti-roll bar softer: less over steer
Usable range: none to 1 inch in diameter
Symptoms of to much adjustment: under steer; slow and boring

Front tire pressure higher: less under steer by reducing slip angels on most tires
Usable adjustment: up to 55psi hot
Symptoms of too much adjustment: no traction- tire crowned so more under steer; adds wheel spin in FF cars; jarring ride; center of tire wears out

Front tire pressure lower: more under steer by increasing slip angles on most tires
Usable adjustment: not less then 20psi
Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up.

Rear tire pressure higher: less over steer by reducing slip angles on most tires
Usable range: up to 45psi hot
Symptoms of too much adjustment: no traction—tire is crowned so more over steer; bad wheel spin on FR cars; jarring ride; center of tire wears out.

Rear tire pressure lower: more over steer by incresing slip angles on most tires.
Usable range: not less then 20psi
Symptoms of too much adjustment: edges of tire wear quickly because tire is folding over; feels mushy; tires chunk because low pressure means heat build up

More negative camber front: less under steer because of better lateral traction as tread is flatter on the ground under side load.
Usable range: up to 3.5 degrees negative
Symptoms of too much adjustment: poor braking; car is road crown sensitive; twitchy; front tires wear on inside edge

More negative camber rear: less over steer because of better lateral traction as tread is flatter on the ground under side load. More rear grip
Usable range: up to 2.5 degrees negative
Symptoms of too much adjustment: more over steer; car feels twitchy in back; tires wear out on inside edge; less breakaway warning when limit is exceeded.

Ride height to low (typical beginner mistake): car is twitchy with unpredictable dynamics. Bump steer make you life miserable.
Usable range: usually 1.5-2.0 inches lower then stock unless car has been modified to go lower.
Symptoms of too much adjustment: everything that could possibly go wrong: sudden over/under steer; twitchy due to bump steer; very harsh ride; premature tire wear.

Toe in – front: car is stable going straight. Turn in is average
Usable range: 0-1/8th inch
Symptoms of too much adjustment: car has slow twitchiness under braking; feels odd; kills outside edge of tires

Toe out – front: Car turns in well; works pretty well on FF car as they tend to toe-in under load.
Usable range: 0-1/4 inch
Symptoms of too much adjustment: Car is really twitchy under braking; car wanders on straight road; kills inside edge of tire

Toe in – rear: car is less likely to over steer when the throttle is lifted
Usable range: 0-1/8th inch
Symptoms of too much adjustment: weird, slow, rocking movement in back; feels slow but still unstable; wears outside edge of tires.

Toe out – rear: Helps car rotate useful in low speed and slalom courses; very common on FF pro rally cars.
Usable range: 0-1/8th inch
Symptoms of too much adjustment: not to good for street driving; causes lift throttle over steer; makes violent side to side rocking motions in the rear; tie wears on inside more.

Positive front caster: helps stability; suspension will get more negative camber when turning; reducing positive caster reduces steering effort. (Negative caster is not usable)
Usable range: 4-9 degrees positive
Symptoms of too much adjustment: can increase under steer especially in cars with wide low-profile tires. Can increase steering effort.

Single adjustable shock stiffer: Better turn in; better transient response; causes slower onset of over/under steer by slowing weight transfer depending on what end of the car is adjusted.
Symptoms of too much adjustment: suspension becomes unresponsive; ride gets harsh; car skips over bumps, loosing traction; Causes a big delay in weight transfer resulting in strange handling like under steer then late corner stage over steer.

Single adjustable shock softer: slower transient response; quicker onset of over/under steer
Symptoms of too much adjustment: car oscillates due to under dampened spring motion, like a boat. Car gets twitchy in turns. Feels unstable.


Here is the secrets stuff of D1 you wanted to know.

Ackerman: Ackerman measns that as you turn your front tires, your tires progressively toe out. cut off your steering arms (on your hub). make arms that you can adjust back and forth (you will probably need a fab shop to do this). Ackerman affects your yaw angle. More ackerman (more progressive toe), less yaw (the less your rear end slides out), less ackerman, more yaw. You can change ackerman by moving the steering arms inboard and outboard. You can measure ackerman statically by turning your wheels and measuring the difference in angle (i.e., the toe change as the wheels are turned)--if wheels are angled out, you have postive ackerman, if angled in you have negative ackerman (from the factory, nissans have positive ackerman) Note that there is more than one definition for ackerman, i.e. some manufacturers call 0 ackerman the factory setting (even though the steering tires progressively toe out)

Bump steer: kazama makes tie rod ends that are adjustable up and down. this affects bump steer. the rear bump steer on a 240sx is adjusted by moving the top, most forward arm connected to the rear hub. Alex (battleversion) makes these arms. when you change height of vehilcle or put on bigger tires, you need to change bump steer on all four wheels. You shoud try for 0 bump steer. bump steer is the amount of steer your wheels make when your car dives and rolls (note that dive is not the same thing as roll). longacre makes a bump steer measuring tool. Bump steer in the rear is more critical than in the front (because you have a steering wheel attached to your front wheels to help you control steering).

Positive caster: more positve caster equals more dynamic camber. Positive caster also increases your front tire slip angles when counter-steering, and pushes your steering into counter steer. In other words it helps a lot with counter steer. About 7 degrees positive caster seems to work best on 240sx's. I would, however like to take out all my static camber and try 9 degrees pos caster and see what happens. Caster, however, causes your front wheels to move (up and down and forward and backward)--which makes it more difficult to control your car, so too much caster is not a good thing. More caster on the right front than the left and your car will tend to pull to the left (and visa-versa), but will decrease the amount your steering wheel will want to push into countersteer (because you are countersteering to the right).

Steering angle: more steering angle, more countersteer. You can increase your steering angle by moving your rack mounts forward (on a car with the rack mounted behind the axle center line) you will probably need a fab shop to do this after you pull out the engine cross member. You can move the rack mounts up to 1 inch forward. This will change your ackerman. So what? You already threw your steering arms away. You can also put extensions on the tie rod ends that mount to the rack. You can get some from kazama (1/4 inch) or you can have a fab shop make them. you can also remove the rod from inside your rack and have a machine shop put more grooves in it. then have the machine shop make extensions as long as you want to screw into the end of the rack rod. this too, will change your ackerman and maybe your bump steer. Make your extensions too long, and you will hit suspension components--but you can just put in a stop.

Mac Strut: this is the reason why your 240sx understeers so much. get a front suspension off a honda accord. measure everything (very, very carefully). mount everything in the same relative place as it was on the honda (you will have to have a rail fabricated to attach your upper a arm and upper shock mount). You will have to also modify your mounting points for your lower control arm and your tension rods--I did not use the tension rods off the honda--i just welded my rods to the honda lc arms--do not know if this is the best way to do it. It might be better to use the tension rods off the honda and keep the mounting points in the right place. You can use your same rack and steering assembly, but will need to modify the honda steering arms--but you are going to cut those off and throw them away and make your own steering arms anyway. You can get skunk upper arms to adjust camber, and can do a 5 lug conversion.



Have fun tuning your suspension. Use Toe and Camber to your advantage! Even Tire pressure helps.

[thekrpa]

Hvala decki pravi ste!

Nisam ocekivao tako brzo odgovore, pa ste me iznendili ugodno!
Sad cu napokon imat znanje o suspensionu!

HVALA JOS JEDNOM!!! O0

[chaos]

Ovako ti izgleda oriđiđi (ala ZaX-ov bolid) suspension za drift i košta oko 1.600 USA $.

http://i19.tinypic.com/2r601he.jpg

[FormatX]

Car setup - cause and effect
Found on another forum, thought it might be useful for someone http://www.sxoc.com/vbb/images/smilies/smile.gif

Carroll Smith's Cause and Effect Guide

RIDE AND ROLL RESISTANCE-SPRING

Too much spring: overall
■ Harsh and choppy ride
■ Much unprovoked sliding
■ Car will not put power down on corner exit - excessive wheel-spin

Relatively too much spring: front
■ Understeer - although the car may initially point in well
■ Front breaks loose over bumps in corners
■ Front tyres lock while braking over bumps

Relatively too much spring: rear
■ Oversteer immediately on application of power
■ Excessive wheel-spin

Too little spring: overall
■ Car contacts the track a lot
■ Floating ride with excess vertical chassis movement, pitch and roll
■ Sloppy and inconsistent response
■ Car slow to take a set � may take more than one

Relatively too little spring: rear
■ Excessive squat on acceleration accompanied by excessive rear negative camber, leading to oversteer and poor power down characteristics
■ Tendency to fall over on outside rear tyre and "flop" into oversteer and wheel-spin

ANTI-ROLL BARS

Too much anti-roll bar: overall
■ Car will be very sudden in response and will have little feel
■ Car will tend to slide or skate rather than taking a set - especially in slow and medium speed corners
■ Car may dart over one wheel or diagonal bumps

Relatively too much anti-roll bar: front
■ Corner entry understeer which usually becomes progressively worse as the driver tries to tighten the corner radius.

Relatively too much anti-roll bar: rear
■ If the imbalance is extreme can cause corner entry oversteer
■ Corner exit oversteer. Car won't put down power but goes directly to oversteer due to inside wheel-spin
■ Excessive sliding on corner exit
■ Car has a violent reaction to major bumps and may be upset by "FIA" kerbs

Too little anti-roll bar: overall
■ Car is lazy in response, generally sloppy
■ Car is reluctant to change direction in chicane and esses

Relatively too little anti-roll bar: front
■ Car "falls over" onto outside tyre on corner entry and then washes out into understeer
■ Car is lazy in direction changes

Relatively too little anti-roll: rear
■ My own opinion is that on most road courses a rear anti-roll bar is a bad thing. Anti-roll bars transfer lateral load from the unladen tyre to the laden tyre - exactly what we don't want at the rear. I would much rather use enough spring to support the rear of the car. The exception comes when there are "washboard ripples" at corner exits, as on street circuits and poorly paved road circuits.

SHOCK ABSORBER FORCES

Too much shock: overall
■ A very sudden car with harsh ride qualities, much sliding and wheel patter
■ Car will not absorb road surface irregularities but crashes over them

Too much rebound force
■ Wheels do not return quickly to road surface after displacement. Inside wheel in a corner may be pulled off the road by the damper while still loaded
■ Car may "jack down" over bumps or in long corners causing a loss of tyre compliance. Car does not power down well at exit of corners when road surface is not extremely smooth

Too much bump force: general
■ Harsh reaction to road surface irregularities.
■ Car slides rather than sticking
■ Car doesn't put power down well - driving wheels hop.

Too much low piston speed bump force
■ Car's reaction to steering input too sudden
■ Car's reaction to lateral and longitudinal load transfer too harsh

Too much high piston speed bump force
■ Car's reaction to minor road surface irregularities too harsh - tyres hop over "chatter bumps" and ripples in braking areas and corner exits.

Too little shock: overall
■ Car floats a lot (the Cadillac ride syndrome) and oscillates after bumps
■ Car dives and squats a lot
■ Car rolls quickly in response to lateral acceleration and may tend to "fall over" onto the outside front tyre during corner entry and outside rear tyre on corner exit.
■ Car is generally sloppy and unresponsive

Too little rebound force: overall
■ Car floats - oscillates after bumps (the Cadillac ride syndrome)

Too little bump force: overall
■ Initial turn in reaction soft and sloppy
■ Excessive and quick roll, dive and squat

Too little low piston speed bump force
■ Car is generally imprecise and sloppy in response to lateral (and, to a lesser extent longitudinal) accelerations and to driver steering inputs

Too little high piston speed bump force
■ Suspension may bottom over the largest bumps on the track resulting in momentary loss of tyre contact and excessive instantaneous loads on suspension and chassis

Dead shock on one corner
■ A dead shock is surprisingly difficult for a driver to identify and/or isolate
- At the rear, the car will "fall over" onto the outside tyre and oversteer in one direction only
- At the front, the car will "fall over" onto the outside tyre on corner entry and then understeer.

WHEEL ALIGNMENT

Front toe-in: too much
■ Car darts over bumps, under heavy braking and during corner entry - is generally unstable
■ Car won't point into corners, or if extreme. May point in very quickly and then dart and wash out

Front toe-out: too much
■ Car wanders under heavy braking and may be somewhat unstable in a straight line, especially in response to single wheel or diagonal bumps and/or wind gusts
■ Car may point into corners and then refuse to take a set
■ If extreme will cause understeer tyre drag in long corners

Rear toe-in: too little
■ Power on oversteer during corner exit

Rear toe-in: too much
■ Rear feels light and unstable during corner entry. Car slides through corners rather than rolling freely

Rear toe-out: any
■ Power oversteer during corner exit and (maybe) in a straight line
■ Straight line instability

Front wheel caster or trail: too little
■ Car too sensitive (twitchy?)
■ Too little steering feel and feedback

Front wheel caster or trail: too much
■ Excessive physical steering effort accompanied by too much self return action and transmittal of road shocks to the drivers hands
■ General lack of sensitivity to steering input due to excessive force required

Front wheel caster or trail: uneven
■ Steering effort is harder in one direction than in the other
■ Car will "pull" towards the side with less caster - good on ovals, bad on road courses

Camber: too much negative
■ Inside of tyre excessively hot and/or wearing too rapidly. At the front this will show up as reduced braking capability and at the rear as reduced acceleration capability. Depending on the racetrack and the characteristics of the individual tyre, inside temperature should be 10°-25° hotter than the outside. Use a real pyrometer with a needle rather than an infra red surface temperature device.

Camber: not enough negative
■ Outside of tyre will be hot and wearing. This should never be and is almost always caused by running static positive camber at the rear in an effort to avoid the generation of excessive negative camber under the influence of aero download at high speed.
- A better solution is improved geometry and increased spring rate. Dynamic positive camber will always degrade rear tyre performance and if extreme, can cause braking instability and/or corner exit oversteer.

Bump steer, front: too much toe-in in bump
■ Car darts over bumps and understeers on corner entry

Bump steer, front: too much toe-out in bump
■ Car wanders under brakes and may dart over one wheel or diagonal bumps
■ Car may understeer after initial turn in

Bump steer, rear: too much toe-in in bump (same as solid axle steer on outside wheel)
■ Roll understeer on corner entry
■ Mid phase corner understeer
■ "Tiptoe" instability when trail braking
■ Darting on power application on corner exit

Bump steer, rear: too much toe-out in bump (same as solid axle steer on outside wheel)
■ Instability on acceleration
■ Good turn in followed by a tendency to oversteer at mid-phase and exit

TYRES

Too much tyre pressure
■ Harsh ride, excessive wheel patter, sliding and wheel-spin
■ High temperature reading and wear at the centre of the tyre

Too little tyre pressure
■ Soft and mushy response
■ Reduced footprint area and reduced traction
■ High temperatures with a dip in the centre of the tread

Front tyres "going off"
■ Gradually increasing understeer - Enter corners slower, get on power earlier with less steering lock

Rear tyres "going off"
■ Gradually increasing power on oversteer - Try to carry more speed through corner and be later and more gradual with power application

LIMITED SLIP MALADIES

Limited slip differential wearing out
■ Initial symptoms are decreased power on understeer or increased power on oversteer and inside wheel spin. The car might be easier to drive, but it will be slow
- When wear becomes extreme, stability under hard acceleration from low speed will diminish and things will not be pleasant at all

Excessive cam or ramp angle on coast side plate (clutch pack) limited slip differential
■ Corner entry, mid-phase and corner exit understeer. Incurable with geometry changes or rates - must change differential ramps. In 1998, virtually everyone is running 0/0 or 80/80 ramps.

SUSPENSION GEOMETRY

Excessive front scrub radius (steering offset)
■ Excessive steering effort accompanied by imprecise and inconsistent "feel" and feedback

Excessive roll centre lateral envelope: front or rear
■ Non-linear response and feel to steering input and lateral "G" (side force) generation

Rear roll centre too low (or front r/c relatively too high)
■ Roll axis too far out of parallel with mass centroid axis, leading to non-linear generation of lateral load transfer and chassis roll as well as the generation of excessive front jacking force.
■ Tendency will be towards understeer

Rear roll centre too high (or front r/c relatively too low)
■ Opposite of above, tending towards excessive jacking at the rear and oversteer

Front track width too narrow relative to rear
■ Car tends to "trip over its front feet" during slow and medium speed corner entry, evidenced by lots of understeer (remember trying to turn your tricycle?)
- Crutch is to increase front ride rate and roll resistance and increase the camber curves in the direction of more negative camber in bump (usually by raising the front roll centre)

INSTABILITY

Straight line instability: general
■ Rear wheel toe-out, either static due to incorrect (or backwards) setting, or dynamic due to bump steer or deflection steer
■ Vast lack of rear download or overwhelming preponderance of front download
■ Wild amount of front toe-in or toe-out
■ Loose or broken chassis, suspension member or suspension link mounting point
■ Dead shock absorber

Straight line instability: under hard acceleration
■ Malfunctioning limited slip differential
■ Insufficient rear toe-in
■ Deflection steer from rear chassis/suspension member or mounting point
■ Rear tyre stagger (car pulls to one side)
■ Dead rear shock absorber
■ Wildly uneven corner weights

Straight line instability: car darts over bumps (especially one wheel bumps)
■ Excessive Ackermann steering geometry
■ Excessive front toe-in or toe-out
■ Uneven front caster or trail settings
■ Insufficient rear wheel droop travel
■ Dead shock or uneven shock forces or incorrectly adjusted packers/bump rubbers
■ Wildly uneven corner weights
■ Front anti-roll bar miles too stiff

Instability under hard braking: front end wanders
■ Excessive front brake bias or uneven corner weights or excessive front damper rebound force

Instability under hard braking: car wants to spin
■ Excessive rear brake bias
■ Insufficient rear droop travel
■ Wildly uneven corner weights
■ Excessive rear damper rebound force
■ Unbalanced ride/roll resistance - too much at rear
■ Insufficient rear camber (usually in combination with one or more of the above)

RESPONSE

Car feels generally too heavy and unresponsive
■ Tyre pressures too low
■ Insufficient ride and/or roll resistance (springs and bars)
■ Excessive aerodynamic download, or insufficient spring for the amount of download
- If high speed acceleration is sluggish, the culprit is often too large a rear wing Gurney lip

Car feels sloppy, is slow to take a set in corners, rolls a lot, doesn't want to change direction
■ Insufficient tyre pressure
■ Insufficient damper forces
■ Car too soft in ride and/or roll

Car responds too quickly "has little feel" slides at the slightest provocation
■ Excessive tyre pressure
■ Excessive bump force in shock absorbers
■ Car too stiff for inexperienced driver
■ Excessive ride or roll resistance
■ Excessive front or rear toe-in
■ Insufficient aerodynamic download

UNDERSTEER

Corner entry understeer: car initially points in and then washes out
■ Excessive toe-in or toe-out (car is usually "darty")
■ Insufficient front droop travel (non droop limited cars only)
■ Incorrectly adjusted packers (car rolls on to packers)
■ Insufficient front damper bump resistance (similar to roll stiffness example)
■ Insufficient front roll stiffness - car may feel like it is pointing in but may actually be falling over onto the outside front tyre due to insufficient front roll stiffness or diagonal load transfer under heavy trail braking. Initial understeer can often be cured by increasing front roll resistance, even though doing so may increase the amount of lateral load transfer.
■ Non linear lateral load transfer due to spring and/or bar geometry. Or to non-optimal roll axis inclination

Corner entry understeer: car won't point in and gets progressively worse
■ Driver braking too hard, too late
■ Relatively narrow front track width
■ Excessive front tyre pressure
■ Excessive front roll stiffness (spring or bar)
■ Relative lack of front download (excessive rear download)
■ Incorrectly adjusted packers or bump rubbers (car rolls onto packers)
■ Insufficient front toe-in
■ Insufficient Ackermann effect in steering geometry
■ Front roll centre too high or too low
■ Insufficient front damper bump force
■ Insufficient front toe-out
■ Insufficient front wheel droop travel (on non droop limited cars only)
■ Nose being "sucked down" due to ground effect
■ Excessive Ackermann steering geometry
■ Can also be caused by unloading the front tyres due to rearward load transfer under acceleration - cures include:
- Increasing front damper rebound force
- Increasing rear damper low speed damper rebound force
- Increasing rear anti-squat
- Droop limiting front suspension (will also make turn in more positive and will reduce overall understeer)

Mid-corner (mid-phase) understeer
■ Excessive front tyre pressure
■ Excessive relative front roll stiffness
■ Excessive front toe (in or out)
■ Excessive Ackermann steering geometry
■ Insufficient front dynamic camber
■ Relatively narrow front track width
■ Insufficient front wheel travel (car rolls onto packers or bottomed shock)
■ Insufficient droop travel (on non droop limited cars)

Corner exit understeer: slow corners
■ Often a function of excessive corner entry and mid-phase understeer (whether driver induced or car induced) followed by throttle application whilst maintaining the understeer steering lock. The first step must be to cure the corner entry and mid-phase understeer. If this is impractical, then corner entry speed should be reduced slightly in order to allow earlier throttle application. Sometimes we have to be patient.

Corner exit understeer: fast corners
■ Relative lack of front download - often caused by negative pitch angle (squat) due to rearward load transfer on acceleration. Can be helped by increasing rear anti-squat and/or by increasing rear low speed bump force, increasing front droop force and by limiting the front suspension droop travel.
■ Relatively narrow front track width
■ Excessive ramp angle or pre-load on clutch pack or plate type limited slip differentials.

Understeer stronger in one direction than in the other
■ Uneven corner weights
■ Uneven caster
■ Uneven camber (especially front)

OVERSTEER

Corner Entry Oversteer
■ Excessively heavy trail braking
■ Excessive rearward brake bias
■ Severe rearward ride rate/roll resistance imbalance
■ Rear roll centre too high
■ Diabolical lack of rear download
■ Severely limited rear droop travel
■ Broken or non-functioning outside rear damper
■ Broken or non-functioning front anti-roll bar

Note: A slight feeling of rear "tiptoe" type hunting on corner entry can be due to excessive rear toe-in or excessive rear damper rebound force.

Mid-corner (mid-phase) oversteer
■ Driver threw the car at the corner to get through initial understeer - only cure is to educate the driver and/or decrease understeer
■ Excessive rear tyre pressure
■ Excessive relative rear ride and/or roll stiffness
■ Rear suspension bottoming in roll
■ Insufficient rear droop travel (non droop limited cars only)
■ Very loose rear anti-roll bar linkage

Corner exit oversteer: gets progressively worse from the time the power is applied
■ Worn out limited slip differential
■ Excessive anti-squat geometry
■ Excessive rear ride and/or roll stiffness
■ Insufficient rear spring, bar or shock (low piston speed bump force) allowing the car to "fall over" onto outside rear tyre
■ Excessive rear negative camber
■ Too little dynamic rear toe-in
■ Relatively insufficient rear download

Note: If car feels as though it is sliding through the corner rather than rolling freely, reduce the rear toe-in and see what happens.

Corner exit oversteer "sudden" - car seems to take a normal exit set and then breaks loose
■ Insufficient rear suspension travel (lifting the inside wheel on non droop limited cars or bottoming the outside suspension due to lack of bump travel)
■ Incorrectly adjusted packers
■ Dead rear damper
■ Sudden change in outside rear tyre camber
■ Too much throttle applied too soon - often after the drivers confidence has been boosted by the car taking a set.

Car does not put the power down smoothly on the exit of smooth corners
■ Worn out limited slip differential
■ Excessive rear ride/roll resistance
■ Excessive anti-squat geometry
■ Excessive rear tyre pressure
■ Tyres gone
■ Excessive rear damper low piston speed bump force
■ Excessive rear dynamic camber - either from download or from camber change on squat
■ Relative lack of rear download

Car does not put the power down on the exit of bumpy corners
■ Any or all of the above for smooth corners
■ Excessive rear damper high piston speed force
■ Excessive rear damper rebound force (jacking down)
■ Insufficient rear droop travel

TRANSITIONS

Understeer in, snap to oversteer on power application
■ The most common complaint of all! Usually caused by too little roll resistance - car falls over on entry and then snaps.
- Increase front bar and/or spring and/or front damper low piston speed bump force. Stiffening the bar will also transfer some load on to the inside rear tyre on acceleration.
- If the suggestion above cures the understeer but the car still snaps, the culprit is almost always the car falling over on the outside rear tyre on longitudinal plus lateral load transfer. Add rear bar or spring. Bar will transfer load away from the inside rear tyre. Spring will not. Spring will, however, decrease traction over exit bumps while bar will not.
■ Loose anti-roll bar linkage/blade sockets can have the exactly same effect

Car is slow to change directions in chicanes or esses
■ Insufficient ride/roll stiffness, especially at front.
■ Relatively narrow front track width.
■ Insufficient front damper low piston speed bump force.

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BRAKES

Brake pedal gets soft, spongy and/or long during session or race
■ Fluid boiling in calipers. Not pad fade! Upgrade fluid and/or cool calipers.

Brake pedal is soft, spongy and/or long before the car is run
■ Air in the system - bleed brakes.
■ Brake pads badly taper worn - replace

Reduced stopping power with normal brake pedal
■ Pad fade - due either to unbedded new pads or to temperature beyond pad capacity. Upgrade pads.

Long pedal with little effort required
■ Master cylinder(s) too small or pedal mechanical advantage too great.

Rough braking - pedal vibrates under pressure
■ Organic pickup on discs - clean discs with garnet paper (not aluminium oxide sandpaper) and upgrade pads
■ Warped (not grooved) rotors. Grind (or, if you must, turn) rotor surfaces
■ Insufficient axial float on floating discs

Uneven braking - car pulls to one side
■ Stuck piston(s) - rebuild calipers

Brake bias changes during application
■ Excessive clearance between master cylinder push rod clevises and bias bar bearing housing.
■ Rod end bearings used instead of clevises on master cylinder push rods.
■ Bias bar incorrectly adjusted. Bar must be perpendicular to vehicle longitudinal axis with full foot pressure applied. Contrary to popular opinion, relative length of master cylinder pushrods is immaterial.