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How does the suspension work

Discussion in 'A4/S4 forum(B5 Chassis)' started by Audijarvis, Mar 13, 2010.

  1. Audijarvis
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    Audijarvis Member

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    I know how the spring and damper works but what do all the control arms etc do?

    Are they there just to keep the hub level or do they also alter the shock characteristics like a rising rate system found on motorcycles?

    A link to an article would be great

    Thanks Jarvis
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  2. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    They wont alter the shock characteristics, but they will add additional spring rate as you compress the suspension due to the bushes twisting.

    The main job is to keep the geometry correct throughout the suspensions range of motion.
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  3. Audijarvis
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    Audijarvis Member

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    'Bushes twisting'= torsion?

    Is this why you suggested changing them in a previous post?
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  4. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    ye, the rubber is bonded to the casing and th centre sleeve, so when the bush rotates on its axis the rubber twists and resists turning.

    The reason for changing them is more down to the geometry. When the bushes get old the rubber becomes weak, and will also delaminate from the steel. This means the suspension arm (or in the case of the rear end, the entire axle) will start to move around a lot more under load, and as a result the geometry will change. The most noticeable one is the rear axle, as when they start to break down and the axle starts to move around, the first you find out about it is when the back end lets go with no warning and you end up facing the wrong way, or in a hedge.

    The front can be pretty knackered without any obvious signs, but when you change them you'll realise what you were missing. Makes the car feel a lot more sure footed and precise, and also stops it rolling around quite as much (especially the rear ones)
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  5. Audijarvis
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    Audijarvis Member

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    Now I see why you suggested replacing them

    I think the reason I find the car more of a handful than the focus is simply the size of the car and possibly the engine position. The first thing I noticed was the fronts tendency to run wide on a neutral throttle, since then I've started to drive through turns and the car steers much better

    Going to stick a set of coil overs on it as money allows and drop it a little, see what that does for the handling
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  6. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    TBH i'd certainly think the money would be better spent sorting the arms and bushes first. Our car is still on standard suspension. I dont personally think coilovers make for a good handling car, as unless you spend a lot of money it just ends up being far too hard.

    At the very least, throw a set of rear axle bushes at it, as they arent dear, and REALLY make a difference.
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