how important is caster?

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sirvaliant_98
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how important is caster?

Post by sirvaliant_98 » Sat Jan 22, 2005 3:40 pm

Well i just got my car aligned after putting the dropzone n1 on. everything came out in the green except my caster on the front. the specified range is 1.60 to 3.60 degrees, mine is left front 3.75 and right front 3.97 and they couldnt do anything about it. I asked them what this would affect. they told me shouldnt really affect wear on parts but it could fight with the handling. anyone have an experience with alignments and caster. any info would be great.

nathan

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Diablo0
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Post by Diablo0 » Sat Jan 22, 2005 3:48 pm

This help you out?

TireRack wrote:Caster

The caster angle identifies the forward or backward slope of a line drawn through the upper and lower steering pivot points when viewed directly from the side of the vehicle. Caster is expressed in degrees and is measured by comparing a line running through the steering system's upper and lower pivot points (typically the upper and lower ball joints of an A-arm or wishbone suspension design, or the lower ball joint and the strut tower mount of a McPherson strut design) to a line drawn perpendicular to the ground. Caster is said to be positive if the line slopes towards the rear of the vehicle at the top, and negative if the line slopes towards the front.

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A very visual example of positive caster is a motorcycle's front steering forks. The forks point forward at the bottom and slope backward at the top. This rearward slope causes the front tire to remain stable when riding straight ahead and tilt towards the inside of the corner when turned.

Caster angle settings allow the vehicle manufacturer to balance steering effort, high speed stability and front end cornering effectiveness.

Increasing the amount of positive caster will increase steering effort and straight line tracking, as well as improve high speed stability and cornering effectiveness. Positive caster also increases tire lean when cornering (almost like having more negative camber) as the steering angle is increased.

What's the downside to positive caster? If the vehicle doesn't have power steering, a noticeable increase in steering effort will be felt as positive caster is increased. Other than that, the effects of positive caster are pretty much "positive," especially increasing the lean of the tire when the vehicle is cornering while returning it to a more upright position when driving straight ahead.


familycar.com wrote:When you turn the steering wheel, the front wheels respond by turning on a pivot attached to the suspension system. Caster is the angle of this steering pivot, measured in degrees, when viewed from the side of the vehicle. If the top of the pivot is leaning toward the rear of the car, then the caster is positive, if it is leaning toward the front, it is negative. If the caster is out of adjustment, it can cause problems in straight line tracking. If the caster is different from side to side, the vehicle will pull to the side with the less positive caster. If the caster is equal but too negative, the steering will be light and the vehicle will wander and be difficult to keep in a straight line. If the caster is equal but too positive, the steering will be heavy and the steering wheel may kick when you hit a bump. Caster has little affect on tire wear.

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The best way to visualize caster is to picture a shopping cart caster. The pivot of this type of caster, while not at an angle, intersects the ground ahead of the wheel contact patch. When the wheel is behind the pivot at the point where it contacts the ground, it is in positive caster. Picture yourself trying to push the cart and keep the wheel ahead of the pivot. The wheel will continually try to turn from straight ahead. That is what happens when a car has the caster set too far negative. Like camber, on many front-wheel-drive vehicles, caster is not adjustable. If the caster is out on these cars, it indicates that something is worn or bent, possibly from an accident, and must be repaired or replaced.
-Jason
Black '02 Neon R/T | White '02 Neon R/T - SRT-4 Engine Swap
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Try not to become a man of success but rather to become a man of value. - Albert Einstein

sirvaliant_98
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Post by sirvaliant_98 » Sat Jan 22, 2005 4:12 pm

so from reading this, i would gather that since i am in positive camber this is actaully a good thing. so positive caster is just that, as it says above a positive thing. thanks for the reading info diablo

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Diablo0
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Post by Diablo0 » Sat Jan 22, 2005 5:31 pm

You got it...

No problem
-Jason
Black '02 Neon R/T | White '02 Neon R/T - SRT-4 Engine Swap
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^^^ no, that isn't what I look like haha
Try not to become a man of success but rather to become a man of value. - Albert Einstein

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