Adjustable caster - Suspension and Brake Forum

Forum Post / Reply
You must log in before you can post or reply to messages.
Adjustable caster
Friday, July 22, 2011 3:29 PM
In light of OEM's new GP im trying to get some info on caster as Mark also is offering a caster adjustable front mount.

After reading on Google and trying to figure out what it does and such in still a little unsure on our cars.

So....that being said is caster adjustment needed on our cars, as from what I can tell it aids in stabilizing the car running straight and steering wheel return to center.

Re: Adjustable caster
Sunday, July 24, 2011 12:13 PM
Needed? For most people here, no. Nice to have? Yes.

Caster adjustable mounts are nice, but you really only adjust them once and that's it, unlike camber, where you may set it for the track and then bring it back for the street.

.



Re: Adjustable caster
Wednesday, August 10, 2011 4:17 PM
James Cahill wrote:Needed? For most people here, no. Nice to have? Yes.

Caster adjustable mounts are nice, but you really only adjust them once and that's it, unlike camber, where you may set it for the track and then bring it back for the street.

.

you use to be my hero, now i serve in the military i am a hero but you just made me urself a hero again!



Image
(write what ever comment you want here)
Re: Adjustable caster
Friday, August 12, 2011 5:34 AM
We need to get a beer. Just like old times.
.



Re: Adjustable caster
Friday, August 12, 2011 8:51 AM
Straight From the internet

THE EFFECTS OF CASTER


Caster is the angle to which the steering pivot axis is tilted forward or rearward from vertical, as viewed from the side. If the pivot axis is tilted backward (that is, the top pivot is positioned farther rearward than the bottom pivot), then the caster is positive; if it's tilted forward, then the caster is negative.

Positive caster tends to straighten the wheel when the vehicle is traveling forward, and thus is used to enhance straight-line stability. The mechanism that causes this tendency is clearly illustrated by the castering front wheels of a shopping cart (above). The steering axis of a shopping cart wheel is set forward of where the wheel contacts the ground. As the cart is pushed forward, the steering axis pulls the wheel along, and since the wheel drags along the ground, it falls directly in line behind the steering axis. The force that causes the wheel to follow the steering axis is proportional to the distance between the steering axis and the wheel-to-ground contact patch-the greater the distance, the greater the force. This distance is referred to as "trail."

Due to many design considerations, it is desirable to have the steering axis of a car's wheel right at the wheel hub. If the steering axis were to be set vertical with this layout, the axis would be coincident with the tire contact patch. The trail would be zero, and no castering would be generated. The wheel would be essentially free to spin about the patch (actually, the tire itself generates a bit of a castering effect due to a phenomenon known as "pneumatic trail," but this effect is much smaller than that created by mechanical castering, so we'll ignore it here). Fortunately, it is possible to create castering by tilting the steering axis in the positive direction. With such an arrangement, the steering axis intersects the ground at a point in front of the tire contact patch, and thus the same effect as seen in the shopping cart casters is achieved.

The tilted steering axis has another important effect on suspension geometry. Since the wheel rotates about a tilted axis, the wheel gains camber as it is turned. This effect is best visualized by imagining the unrealistically extreme case where the steering axis would be horizontal-as the steering wheel is turned, the road wheel would simply change camber rather than direction. This effect causes the outside wheel in a turn to gain negative camber, while the inside wheel gains positive camber. These camber changes are generally favorable for cornering, although it is possible to overdo it.

Most cars are not particularly sensitive to caster settings. Nevertheless, it is important to ensure that the caster is the same on both sides of the car to avoid the tendency to pull to one side. While greater caster angles serve to improve straight-line stability, they also cause an increase in steering effort. Three to five degrees of positive caster is the typical range of settings, with lower angles being used on heavier vehicles to keep the steering effort reasonable.




http://www.overkillengineeringmotorsports.com/
Forum Post / Reply
You must log in before you can post or reply to messages.

 

Start New Topic Advanced Search