Quote:
Originally Posted by babydriver
Of course there is another factor at work and that is damping (the shock absorber). The damping would be enough to eliminate any oscillations from the lower rate (as you say, a lower resonant frequency too). I'm assuming though that there has to be an optimum spring rate for each unsprung mass designed to achieve certain goals of handling and traction, otherwise all car manufacturer would use the same springs. Toyota went to the trouble to change the spring rates on the 2015 FR-S compared to the two previous years to improve handling. They must have had their reasons.
I'll look forward to your later post, Ultramarine.
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Springs absorb bumps and shocks control springs and body motion.
Spring rates are mostly meaningless to talk about from a modeling perspective because of differing motion ratios for different suspensions and makes. Resonant frequency/wheel rate is the real measurement. Lighter unsprung weight is basically almost linear w increasing the wheel rate.
10% less unsprung weight is basically similar to 10% stiffer springs in terms of wheel rate. Ie if your wheel rate was 1.5, now it is 1.65
Generally lower wheel rates (like 1) makes for more comfort and better traction, but needs more suspension travel. So wheel rates are mostly governed by bump travel and expected hauling weight of the car. Most cars have rates around 1.2 or so and end up needing at least like 6 inches bump travel Minimum. Most non-aero driven pure track cars aim for 3 inches bump travel which ends up at wheel rates around 2.5. sports cars end up in the middle.
roll angle is harmless in steady state but bad in transitions and makes drivers unhappy if there is too little or too much. Anti roll bars are to control roll angles.
shocks control body motion at low shock speeds and control for bumps at high shock speeds.
Edit: the wheels also count for rotational mass, which does help acceleration and braking
second edit: I think I have something wrong with the unsprung weight. Please ignore the wrong half of this post. which half is wrong I'm not quite sure. ahaha