Suspension Theory/Dynamics

Camber

Ok so what is camber...say you are looking at your car dead on from the front...the wheels will look like / \ or \ /. Thus, camber is the angle of tilt on the wheels(tilting either upwards or downwards). now what is this and why am i even telling you about it? well it's simple: if the wheels are like this: / \ this means it has negative camber. negative camber will give you better grip on whichever hand has more negative camber. because you see, when your car is turning, there is body lean...and most of the car's mass is supported by 1 side of the suspension. thus, there will be flexing in the bushings and the tires will be tilted. for example...say the car is turning right, the car will lean to the left right? right. that's body roll. simple physics...now when this is happening and you dont have any camber, if u looked at your front wheels from the front, the angle will be like this during hard cornering: \ | meaning the outside tire(left tire that is supporting all the weight) is being bent on a downward angle making the tire have less of a contact patch on the ground. negative camber reduces or totally eliminates this effect by giving the wheels a natural upward tilt which will make up for the flexing in the suspension. so say now u have negative camber(/ \) and you are making a hard right turn...your front wheels when viewed from the front will then look like this: | \ thus the left side which is supporting most of the car's weight will inherit more traction from the initial angle provided by camber adjustments.

Now after explaining all that mumbo jumbo, what good is positive camber? well...it is to reduce traction. it is the exact opposite of what was described and some people will run a +0.5 camber or so to reduce traction on whichever end of the car they want. it's all in the driving preferences of the driver.

Toe in/Toe out

Toe is the wheels facing inward or outwards. if you view your car from the top, the wheels can look like this if it has toe: / $toe in) or \ /(toe out). well now you know what toe is....but so what does it do? well...i'd have to draw some pictures or something but i cant do that right now, so u'd have to use ur imagination. basically, when your wheels are turned and say u have a toe in setting, the outside wheel will be turned more than the inside wheel, right? if u dont get it, it is because the inside wheel is ALWAYS pointing inwards...think about it. look back at what toe in is(/ $ and imagine turning ur wheels. get it? ok. Well what this does is slow down your car's initial turn in response...gives the car more straight line stability and helps the car to oversteer more during mid corner or exit of the corner.

So if your car had toe out and you are looking at the steering angle of the wheels then your inside wheel will be turning more sharply than the outside wheel. thus in this setting, the outside wheel is ALWAYS pointed more outwards than the inside wheel. well what does this do? this gives a better/faster/quicker turn in response. it makes the car more twitchy and hairy, reduces straight line stability but makes for quick transitions really easy to do.

What about the rear wheels? all along i've been talking about the front wheels...well if the back wheels have toe in, u will have more stability(because think about it, when going forwards...the wheels are working against each other[pushing into each other] and thrusting backwards at the same time). with toe out, it is the opposite, u have less stability but it enables the car to be more tossable.

Sway bars

These are commonly referred to as "sway bars" but are actually "anti-sway bars". they connect one lower control arm to the other so that when the car leans, the bar will push up the opposite side and reduce the body roll induced by the g forces.(need pics here once again to demonstrate...will get those sometime)

whichever end has the thicker bar is the end that is going to lose more traction...so the swaybar is a good tuning adjustment in order to get the understeer/oversteer that you want to acheive.

Spring Rates

Spring rates...spring rates is how stiff your springs are. these are usually measured in kg/mm or lbs/in. if you are made of $ and would like to order yourself several sets of ground control coil over springs with custom rates then u are king! u can then customize how your car will handle by getting custom rates...now how does this work? well usually, whichever end has the stiffer rate is the end that is going to lose more traction. so if u want oversteer u get really stiff rears and if u want understeer u get really stiff fronts...a common way that i read about to acheive a neutral balance is to use some pretty conventional springs(ie: H&R race) and fool with sway bars.

Dampening

Dampening is how much resistance the shocks/struts put on the springs when the springs rebound after compressing. therefore, it controls the speed at which the whole suspension rises back up as well as how fast the entire suspension reacts to undulations on the road.

A poor man's way of adjusting "rates" and acheiving a minor handling difference is to get adjustable dampers such as Tokico Illuminas and stiffening up the rear dampening rates and leaving the front at the lowest possible...this would reduce the amount of understeer the car is getting.

Real life examples of suspension settings

My friend Vivek runs something like 2.5kgmm front springs and 6kgmm rear springs with a 22mm rear sway bar and no front sway bar on an EF civic. this equals oversteer even though he doesnt seem to think he has enough =)

My friend Cyril ran 5kgmm springs all around on his ae86 which would give what i think would be oversteer...but i have never driven it so i am not sure and he was running on stock sways...

Why too stiff is not always good

So say you slammmmmm your car 3.5 inches and it looks siiiiiick and as a result from so much slammage, the car has some serious chamber going on and the springs are like 7.5kgmm all around and your car is a 1985 VW Sirrocco.

is this good? NO!!!!!!!! why would you want that? cos it looks kool and as a result from the stuff rates and mad camber ur car will handle good? i'm sorry, that's not true. the camber settings will be all off and might even be too much resulting in not large enough of a contact patch from the tires when the car is turning....so traction is reduced.

now the stiff rates..why on earth would anyone want such stiff rates on such a light and small car...you still need a certain amount of body lean so that you can transfer the weight of the car from right to left and front to back! otherwise it'd be pretty crappy to drive around..

Caster

Caster is when your wheels are turned, there is a certain vertical tilt angle to them...ie) wheels are turned right...and you are looking at the wheels from inside the car(pretend u got windows on the floor or something ok? -_-)...then on the right hand side wheel(outside wheel) you will have negative camber...on the left hand side wheel(inside wheel) you will have postive camber...now think about this...if your car was turning, the forces would push against the wheels and make both of them postive camber if u dont have caster....with caster, your wheels will be flat on the ground because it counter acts the forces....bleh, i suck at explaining...i hope u understand it =)

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