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Overcritical damping
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(36 posts, started )
Quote from Shotglass :99.9% of all hatchbacks use trailing arms which do have a pronounced anti dive effect

Easily observed by the car squatting when pulling the handbrake (or is that a different effect in action?).
Actually trailing arms prevent the reward pitching so I would say that they produce mainly an anti squat effect.
But hmm yeah guessing from the oposit effect that happens when you activate the rear brakes, it will help reduce dive while braking.

In McPherson struts, doesn't caster also produce some antidive characteristics?
Quote from NightShift :Of course not, otherwise there would be no point in fitting soft springs to a road car. In my posts, I was talking about the excessive suspension travel that we see in LFS whenever we use realistic values (i.e. taken from real car specs) rather than the bottoming out.

E.g. if you take the FXO and set it up with values (e.g. <30 N/mm), you'll see the front extend to dramatic results as soon as it goes uphill a bit.

My source stated preload limits excessive suspension travel and then went on to say 'on race cars preload isn't used anyway' so it did not explain in detail how this is supposed to work, if you can suggest any good links I'd be grateful

Regarding anti-dive (and therefore anti-squat as one is rarely used without the other) I was referring to the front suspension. I am aware that the nature of trailing arms doing funny things to suspension movement.

Anti dive and anti squat do not alter the amount of longitudinal load transfer. Using anti squat on a FWD car will not stop load transfer to the rear (other than by possibly stopping the CoG height to increase with pitch, but that's pretty negligable anyway), and so does not assist with traction in that way. Effectively anti-squat and anti-dive is just the suspension locking up (albeit in a vaguely controlled, linear way) and going all stiff and horrid, and is mostly used intentionally as an aerodynamic aid in race car design.

Spring preload is used in race cars a lot, often with droop limiters to maintain a half decent aero platform at all times without making the chassis springing unduly horrid. It is rarely used in road cars other than a small amount to stop the springs moving around on full droop.
Quote from tristancliffe :Anti dive and anti squat do not alter the amount of longitudinal load transfer.

But ride height does, then improved suspensions would allow for lower cars without touching springs or dampers. Of course nobody would stop you from making them even stiffer, thus further reducing weight transfer.

Does anybody have good links about spring preload?
Can't find anything useful and it's been two days googling already.
Quote from Bob Smith :Easily observed by the car squatting when pulling the handbrake (or is that a different effect in action?).

doubt it
handbrake lowriding is quite good fun when youre bored while driving slowly

Quote from tristancliffe :other than by possibly stopping the CoG height to increase with pitch, but that's pretty negligable anyway

the height of the cog is a major factor in load transfer

Quote from NightShift :Does anybody have good links about spring preload?
Can't find anything useful and it's been two days googling already. stiffness,

when tristan here isnt busy buying new wings for his f3s he likes to start informative threads some of them about preload
http://www.lfsforum.net/showthread.php?t=30599
Quote from Shotglass :the height of the cog is a major factor in load transfer

Tristan wasn't implying it wasn't. The change in CoG height even with full braking seems to be less than half a centimeter even on soft setups. This makes sense the rear is going to lift up a similar amount to what the front would compress, and the CoG will be nearish to the rotation point of the body.
i cant find it anywhere right now but theres a video floating round the internet of a bmw under full braking and you can clearly see the car diving at first and then just a moment later squatting down visibly at the rear probably by around 5-10cm which will make a difference in cog height
So the back end compresses while the front end remains compressed?
Bike swingarms, being simpler versions of a car's trailing arm suspension, also exhibit this anti-squat under accel and anti-dive under decel behavior. The forks, however, do not exhibit any of that behavior.

Imagine you have the rear wheel on a motorbike locked up so that the wheel and swingarm are one solid unit pivoting in the frame. If you try and push the bike backwards, the rear wheel resists and produces an anti-clockwise (looking from the right side with the front to our right) torque around the swingarm pivot, raising the rear of the bike. This is what happens under accel. Vice versa for braking.
Quote from Bob Smith :So the back end compresses while the front end remains compressed?

yup the car goes from trying to dive to completely flat and looks almost like its squatting a bit from what i remember
BUMP!


Was there a conclusion it over critical dampening is beneficial or a hindrance under certain circumstances?

The articles posted by Bob are either wont load or are archived somewhere.
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Overcritical damping
(36 posts, started )
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