Upper and lower control arms question.
10-27-2008, 07:33 AM
#1
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Location: California
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Upper and lower control arms question.
K, this might be a dumb question, actually i'm fairly certain it is, but i havent really done any suspension modding and cant find any real good write-ups on what i'm looking for. What do upper and lower control arms do? How do they benefit you, whats the difference in offsetting them, what the hell is camber? Uhm, oh and err... yea... *hides*
P.S. Please direct all the answers to that bush... the one i'm NOT hiding behind....*whistles*
P.S. Please direct all the answers to that bush... the one i'm NOT hiding behind....*whistles*
10-27-2008, 08:46 AM
#2
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Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
Control arms, ummm, control the motion of the wheels as the suspension moves due to bumps/dips in the road and from the forces of braking, accelerating, and cornering. Which end are you interested in here?
Aftermarket rear control arms are usually supplied with stiffer bushings or even rod ends. More accurate "geometry" due to less "squish" than with OE bushings. Less likely to give wheel hop because there is less bushing compression to suddenly relieve itself and let things spring back. More noise/vibration/harshness (NVH), and perhaps some suspension "bind" under some circumstances. These are the arms mounted in generally a fore/aft direction. The lateral link up behind the pumpkin is also known as the Panhard bar (PHB). Technically, this is also a control arm, but it is almost never referred to as such.
Up front, you only have lowers. The struts take care of what uppers do up front in other cars. For analysis purposes only, a strut is considered to have a virtual (IOW, imaginary) upper control arm associated with it.
Camber. As you look at your car from either straight behind or straight ahead of it, the is the angle that the wheels are slightly not vertical. Negative camber is with the tops of the wheels closer together than they are at the ground. Usually this only comes up when discussing the front suspension and its alignment, though it also applies the the rear even though it is a "rigid" axle.
Hides = what you roast during a burnout (the most common automotive usage anyway).
Norm
Aftermarket rear control arms are usually supplied with stiffer bushings or even rod ends. More accurate "geometry" due to less "squish" than with OE bushings. Less likely to give wheel hop because there is less bushing compression to suddenly relieve itself and let things spring back. More noise/vibration/harshness (NVH), and perhaps some suspension "bind" under some circumstances. These are the arms mounted in generally a fore/aft direction. The lateral link up behind the pumpkin is also known as the Panhard bar (PHB). Technically, this is also a control arm, but it is almost never referred to as such.
Up front, you only have lowers. The struts take care of what uppers do up front in other cars. For analysis purposes only, a strut is considered to have a virtual (IOW, imaginary) upper control arm associated with it.
Camber. As you look at your car from either straight behind or straight ahead of it, the is the angle that the wheels are slightly not vertical. Negative camber is with the tops of the wheels closer together than they are at the ground. Usually this only comes up when discussing the front suspension and its alignment, though it also applies the the rear even though it is a "rigid" axle.
Hides = what you roast during a burnout (the most common automotive usage anyway).
Norm
Last edited by Norm Peterson; 10-27-2008 at 08:50 AM.
10-27-2008, 11:40 AM
#4
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
Yes.
All S197's have the same basic suspension arrangement. The differences are in the spring rates, sta-bar sizes (and whether there even is a rear bar), control arm bushing rates, and perhaps shock/strut damping curves. Convertibles have some additional chassis stiffening.
Norm
All S197's have the same basic suspension arrangement. The differences are in the spring rates, sta-bar sizes (and whether there even is a rear bar), control arm bushing rates, and perhaps shock/strut damping curves. Convertibles have some additional chassis stiffening.
Norm
10-27-2008, 12:11 PM
#5
Join Date: Apr 2008
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10-27-2008, 01:04 PM
#6
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Join Date: Feb 2007
Location: state of confusion
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First quickie impression, page 1 only - that looks like a pretty good link, though there is room for argument as regards trying to minimize the vertical distance between CG height and roll center heights.
Roll is reduced, but the car then becomes less sensitive to adjustments for tuning the handling. IOW, it takes bigger changes in spring rate or bar diameter to effect a given change in handling, which is generally not a good thing (there is such a thing as being too stiff for the car's usage, even if it's racing).
Norm
Roll is reduced, but the car then becomes less sensitive to adjustments for tuning the handling. IOW, it takes bigger changes in spring rate or bar diameter to effect a given change in handling, which is generally not a good thing (there is such a thing as being too stiff for the car's usage, even if it's racing).
Norm
Last edited by Norm Peterson; 10-27-2008 at 01:09 PM.
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