svaillan
03-20-2009, 08:14 PM
For this write up I am going to only focus on the three main settings for you alignment, I will cover corner balancing and suspension frequency and tire pressure as well as what suspension specs for FWD vs. RWD later. The three factors that you are going to get on your alignment sheet are Camber, Caster and Toe. All these have a very large effect on the way your car responds and can either help or hinder your performance package.
Camber- Camber is the inclination of the wheel when looking from the front to the rear, or rear to the front of a car. A wheel inclined inwards at the top of the wheel will have negative camber and a wheel inclined outward will have positive camber. Positive camber is used on most cars sold for the average Joe, positive camber encourages understeer and makes that wonderful howling noise that your mom hears in her mini van when she is in a hurry to get you to school and driving a little to fast. The simple fact is that positive camber while not good for handling encourages safe driving and for most people that is all they can handle. Negative camber, now this is what you are looking for if you are interested in performance driving. Negative camber first off will give you camber thrust threw corner; this is because the tire is already angled into the corner it wants to turn. Under normal driving in a straight line both tires have the same traction coefficient so the car is not being pulled in either direction, however once you enter a corner and traction is transferred off the inside wheels to the outside wheel which now have a higher traction coefficient with any force coming from the unloaded side of the car; the result is camber thrust forcing you into the turn. This in not the only good thing about negative camber, as the car turns weight is transferred to the outside tires and the tire rolls over. With negative camber as the tire rolls over more and more of the tire is coming in contact with the road surface which is in turn giving you better traction. However like everything else to much is not good, a lot of negative camber will limit the amount of tire that is in contact with the road during straight line driving limiting your ability to accelerate and brake, a lot of negative camber also causes drag during straight line driving so you will have to find a good medium depending on your car and the track that you plan to drive on.
Caster- Caster is the inclination of the kingpin, or upright, as you are looking at it from the side. In simpler terms caster is how much your suspension is angled forward (positive caster). If some of you are still having trouble wrapping your brains around this think of it this way on a bike are a motorcycle the front wheel is angled forward making the bike stable this is positive caster, now think about if you were to spin the wheel around and have it angled back (negative caster) the bike becomes hard to control and very unstable. So positive caster is a good thing, it helps make the car more stable as it moves forward and it centers the wheel after turning. Caster also affects camber when the wheel is turned, the more positive caster you have the more negative camber it will generate on the outside tire when turning so it is a good idea to keep this in mind when adjusting for optimum camber angle. Now for the downside of caster, the more positive camber you have the more the wheels of you car want to center so the heaver (harder to turn) your steering is going to be, you will again have to find a good medium.
Toe- Toe can be either “toe-in” or “toe-out” it is the angel of either the two front or two rear tires looking at them from above. Toe-in is when the front of the tires are closer then the back of the tires and to out is when the front of the tires is further apart then the back of the tires. Toe also plays a large part in your general car’s straight line stability as well as how quickly a car responds to initial turn into a corner. Generally front wheel toe in results in initial understeer where toe-out results in oversteer. Rear wheel toe out should be avoided because it cause your car to be unstable. Another fact that should be taken into account with toe is that drive wheels will toe-in under acceleration so in some cases it might be wise to adjust your toe so that you get the desired toe settings in regards to your drive wheels while you are accelerating. Another fact to think about is how much toe you really want, weather is toe-in or toe-out, when you are traveling in a straight line and one of you’re wheels losses traction just as in camber thrust the other will take over. If you have a lot of toe-in or toe-out once one wheel losses traction the other will drive in the direction of your toe even with the wheels straight. With toe even though your wheels are pointed straight the are either offset in out so in effect they are in fact turned a little and you have to understand how this is going to effect your car.
Common misconceptions about alignment settings and basic trouble shooting.
By far the biggest misconception about alignment setting is that a lot of negative camber will destroy your tires. I can’t tell you how many threads I have read where people state that you are wearing your tires because to much negative camber. The truth is that a lot of negative camber may have a small effect on your tire where over a period of thousands but if you are going through tires very quickly the reason is that you have either to much toe-in or toe-out….. (TOE IS THE CAUSE EXCESS TIRE WEAR).
Another problem that comes up a lot is people’s car are pulling to one side, this can be caused by offset toe, camber, or caster on one side or the other. If you are having issues with your car pulling to one side or the other check your alignment specs but also check for bent A arms or other suspension components that may have been damaged while you were driving.
Adjusting your alignment, camber is not hard to adjust even without the proper equipment as long as you have a camber kits but toe however must be measured from the center of the tire at axel height. If you are good with tools you can make yourself a tool for measuring your toe but it is not east or accurate. Caster on many cars in not adjustable without caster plates or modifying your subframe. This is getting to be a little long so I am going to stop here, again if anyone has any input or questions please post them.
Camber- Camber is the inclination of the wheel when looking from the front to the rear, or rear to the front of a car. A wheel inclined inwards at the top of the wheel will have negative camber and a wheel inclined outward will have positive camber. Positive camber is used on most cars sold for the average Joe, positive camber encourages understeer and makes that wonderful howling noise that your mom hears in her mini van when she is in a hurry to get you to school and driving a little to fast. The simple fact is that positive camber while not good for handling encourages safe driving and for most people that is all they can handle. Negative camber, now this is what you are looking for if you are interested in performance driving. Negative camber first off will give you camber thrust threw corner; this is because the tire is already angled into the corner it wants to turn. Under normal driving in a straight line both tires have the same traction coefficient so the car is not being pulled in either direction, however once you enter a corner and traction is transferred off the inside wheels to the outside wheel which now have a higher traction coefficient with any force coming from the unloaded side of the car; the result is camber thrust forcing you into the turn. This in not the only good thing about negative camber, as the car turns weight is transferred to the outside tires and the tire rolls over. With negative camber as the tire rolls over more and more of the tire is coming in contact with the road surface which is in turn giving you better traction. However like everything else to much is not good, a lot of negative camber will limit the amount of tire that is in contact with the road during straight line driving limiting your ability to accelerate and brake, a lot of negative camber also causes drag during straight line driving so you will have to find a good medium depending on your car and the track that you plan to drive on.
Caster- Caster is the inclination of the kingpin, or upright, as you are looking at it from the side. In simpler terms caster is how much your suspension is angled forward (positive caster). If some of you are still having trouble wrapping your brains around this think of it this way on a bike are a motorcycle the front wheel is angled forward making the bike stable this is positive caster, now think about if you were to spin the wheel around and have it angled back (negative caster) the bike becomes hard to control and very unstable. So positive caster is a good thing, it helps make the car more stable as it moves forward and it centers the wheel after turning. Caster also affects camber when the wheel is turned, the more positive caster you have the more negative camber it will generate on the outside tire when turning so it is a good idea to keep this in mind when adjusting for optimum camber angle. Now for the downside of caster, the more positive camber you have the more the wheels of you car want to center so the heaver (harder to turn) your steering is going to be, you will again have to find a good medium.
Toe- Toe can be either “toe-in” or “toe-out” it is the angel of either the two front or two rear tires looking at them from above. Toe-in is when the front of the tires are closer then the back of the tires and to out is when the front of the tires is further apart then the back of the tires. Toe also plays a large part in your general car’s straight line stability as well as how quickly a car responds to initial turn into a corner. Generally front wheel toe in results in initial understeer where toe-out results in oversteer. Rear wheel toe out should be avoided because it cause your car to be unstable. Another fact that should be taken into account with toe is that drive wheels will toe-in under acceleration so in some cases it might be wise to adjust your toe so that you get the desired toe settings in regards to your drive wheels while you are accelerating. Another fact to think about is how much toe you really want, weather is toe-in or toe-out, when you are traveling in a straight line and one of you’re wheels losses traction just as in camber thrust the other will take over. If you have a lot of toe-in or toe-out once one wheel losses traction the other will drive in the direction of your toe even with the wheels straight. With toe even though your wheels are pointed straight the are either offset in out so in effect they are in fact turned a little and you have to understand how this is going to effect your car.
Common misconceptions about alignment settings and basic trouble shooting.
By far the biggest misconception about alignment setting is that a lot of negative camber will destroy your tires. I can’t tell you how many threads I have read where people state that you are wearing your tires because to much negative camber. The truth is that a lot of negative camber may have a small effect on your tire where over a period of thousands but if you are going through tires very quickly the reason is that you have either to much toe-in or toe-out….. (TOE IS THE CAUSE EXCESS TIRE WEAR).
Another problem that comes up a lot is people’s car are pulling to one side, this can be caused by offset toe, camber, or caster on one side or the other. If you are having issues with your car pulling to one side or the other check your alignment specs but also check for bent A arms or other suspension components that may have been damaged while you were driving.
Adjusting your alignment, camber is not hard to adjust even without the proper equipment as long as you have a camber kits but toe however must be measured from the center of the tire at axel height. If you are good with tools you can make yourself a tool for measuring your toe but it is not east or accurate. Caster on many cars in not adjustable without caster plates or modifying your subframe. This is getting to be a little long so I am going to stop here, again if anyone has any input or questions please post them.