Alignment
Basic guide to wheel alignment settings
Covered in this guide:
Camber
Toe
Castor
Before we start - this is a guide to the effects of alignment settings, NOT a definitive guide on how to set your car up. Different people want different things, and arguments rage across the internet about the 'ideal' drift setup, but it all comes down to your skill level, driving style, type of car and how you like the car to feel.
However, the basics transcend car types and can be applied to any vehicle.
I've been all over the net looking for information to base this on - and if you KNOW different to what is written here - LET US KNOW, we'll have a research and maybe add your testament or setup into the mix at the end.
Remember - extreme adjustments are for sceners - if you want -15 degrees of camber, you need to get to stanceworks :-D
Bear in mind - adjusting one setting may well move other settings - so a set-up session with proper gauges that monitor all the geometry at once is recommeded.
First things first - TOE.
What is toe? Imagine standing upright , looking at your feet. Now imagine your feet are your front (or rear) wheels. Move your toes so they are pointing away from each other - this is toe-out. The opposite is toe-in.
Most cars come from the factory set up with a pretty 'normal' setup, meaning that they are pretty close to parallel. This is the recommended starting setting (parallel).
As a rule, toe-in creates stability at the expense of response, and toe-out enhances and sharpens response at the expense of outright stability.
Rear toe settings.
Most drifters tend to run with as close to parallel on the rear as possible - adding toe-in on the rear will make it harder to initiate (because the rear wil be more planted), and when grip is regained, it will do so quite suddenly. However, error on the side of toe-in is preferred as running rear toe-out wil make the car very jittery and difficult to drive with any confidence.
Front toe settings.
Front toe-in aids straight line stability at speed at the cost of slower turn in - and front toe out will make it twitchier at speed but turn in quicker. But going too far will end up making the car unstable at any kind of speed. If you go too far the car will become very snappy and difficult to drive - and thoroughly excessive toe settings on the front will mean that the front tyres are always on the verge of losing grip - again, not inspiring confidence and promoting the dreaded understeer. For a starting figure, look to be having about 1-2mm of toe-out, and you won't be far off (as a starting point).
Now cool stuff - CAMBERZ.
What is camber? Camber is the angle of the wheel in relation to upright, measured in degrees. If the wheel leans in at the top, it's NEGATIVE camber, and if it leans out at the top, it's POSITIVE camber. A perfectly perpendicular wheel is NEUTRAL, or zero degrees.
For the denser among us, here's some visual aids :-D
NEGATIVE CAMBER:
POSITIVE CAMBER:
Yeah, they're extreme, but they get the point across. Now we need to look at the effects of camber settings, on the front and the rear.
Often you don't have a choice but to consider camber settings - although on many cars it isn't adjustable from the factory. When you lower a car significantly, the travel of the suspension will often introduce a shedload of negative camber.
Rear camber.
Example: standard E30 suspension with cut springs gave this much rear camber:
That's quite a lot. And although it looks cool and helps fit wheels in the arches (the lean helps to tuck the wheels under the arches when running very low ride heights) it's not optimum for drifting as the contact patch is very small, leading to the mental inner edge tyre wear that E30s are known for (often tyres that have blown out on the inner edge can have up to 5mm of tread left on the outer edge) and very little grip (the tyre contact patch is very small, as the car is resting on the inner edge of the tyre).
It can also make the car a bit unpredicatable - as you tip the car into a drift, more of the outer tyre comes into contact with the surface (planting the tyre) and as a result grip levels increase. When transitioning this can lead to a situation where the car's grip levels go from higher to lower as the car reaches the straight ahead position and then back to more grip as angle is achieved in the opposite direction.
Where possible, most people would suggest running as close to neutral camber (zero degrees) as possible, perhaps erring on the side of a little negative camber for increased grip and control when drifting combined with a flat tyre wear pattern.
Recommended start figure: 0 degrees (upright, neutral).
Front camber.
Generally with McPhearson strut suspension the front camber won't change when you lower your car. The only time to consider adjusting this is when you feel the need to set your car up - and many, many people run with the standard setting (which is generally pretty much neutral).
The effects of altering the front camber can be a lot more dramatic than the rear, and can make dramatic changes to the feel of a car, both in a straight line and on lock.
The idea is to put as much of the tyre in contact with the ground as possible, for as much of the time as possible. For this, you'll probably want a little negative camber on the front wheels, to plant them into the tarmac when turning in. Too much camber (either way) will reduce the contact patch and reduce front end grip. Somewhere in the region of 2.5 degrees of negative camber (give or take half a degree) seems to be about right for a good compromise between turn in and stability. A bit of negative camber on the front can also help with self centring. Positive camber is to be avoided if at all possible.
Recommended start figure: -2 degrees.
And a scary one - CASTOR.
WTF is castor? Castor is the angle between the line through the top and bottom hub mounts and the vertical steering axis. Here's a pic to help you get your head around it:
"Caster" wheels on a shopping trolley are a good way to visualise this, the pivot is offset from the centre of the wheel, so as the trolley is pushed the wheel rotates to follow the direction of movement. The further the pivot is away from the wheel centre, the more accurately the wheel follows the direction of travel but the slower the response (very marginally). Therefore an extreme amount of caster will make the self centring sluggish - on the flip side, running negative castor will result in death.
There is also castor trail (or castor offset) to consider. This is the distance on the ground between where the green line in the diagram would touches the ground and the point where the wheel touches the ground (the distance between the red and green lines in the diagram). This alters with wheel/ tyre size and effects self centring. The more castor is dialled in (increasing the castor trail), the more self centring effect is applied (meaning that running larger diameter wheels and tyres increases self centring and vice-versa).
Now we have a vague idea of what castor is - why do we want it? Increased castor makes the front wheels 'tip' or give more camber when on lock. Here's a pic to show you what we mean:
When straight ahead the 2CV has no front camber, but thanks to the huuge castor angle, when some lock is applied the front wheels take on so much camber they look like they're going to fall off. Probably to counteract the fact it came from Citroen on space saver wheels, and give it the ability to go round corners.
Adding front castor has the effect of planting the front wheels when on lock (hopefully most of the time), helps self centring effect (because the front wheels naturally want to 'tip' back to where they were) and tones down any sharp steering inputs (helpful when winding a shedload of lock on and off quickly).
Generally beneficial, so add as much as you can :-D
Wheel offset.
Many people choose their wheels solely with style in mind, but it's worth remembering that the offset of your shiny new wheels will probably effect the handling of your car (unless of course they are exactly the same dimensions as the originals). The biggest difference is likely to be in offset.
So.. what is offset? Offset is the measurement from the centreline of the wheel rim to the mounting face, often expressed as an ET value, e.g. ET40, ET-10 etc.
Wheels are usually stamped with their offset using the German prefix "ET", meaning "Einpresstiefe" or, literally, "insertion depth".. ooer.
FWD cars generally have a very high offset (to deal with the way power is delivered unevenly through the front wheels) so bear this in mind when locating secondhand wheels.
Visual aid time :-D
POSITIVE OFFSET:
ZERO OFFSET:
NEGATIVE OFFSET:
As you can hopefully see, it has the effect of moving the rim of the wheel in and out in relation to the mounting face of the wheel. This also has the effect of altering the track width of the car.
As we all know, low offset wheels look cool - and they improve stability - perhaps at the cost of wheel bearing wear. Another upside is that the increased leverage on the hubs translates as more feel of the road at the steering wheel (imperfections in the road tend to be transmitted more forcefully through the steering).
Low offset wheels tend to be very expensive - they are much in demand - however the effects can be achieved (if not the dishy look) by fitting wheel spacers (avaliable from 1-2mm slip on shims to 30mm+ bolt on jobbies) which alter the mounting face position relative to the centre line of the rim.
When people tel you that 'their' setting is the best setup for drifting - tell them to fuck off. It's all down to making the car as predictable and settled as possible. Whenever you are fighting a jittery or over-responsive car you won't have the confidence in it to throw it in hard and KNOW it's going to do what you tell it to.
The best setup for YOUR car is YOUR tried and tested setup.
This guide is for DRIFTING - the setup for a fast road car or a race/ time attack car will be much different.
Now get the spanners out and set up your skid car :-D Good luck.
