Algodoo

This suspension is very smooth. You can use it as a Phunlet or a base of a car, or just as a testing car for a track.

Don't rate the scene - it's crappy, rate the car's suspension. Also if you are going to use this in a car scene, don't delete the top black bar, I know it's non-colliding, but you can just attach a bar higher up on it so the wheels can still flex but not hit the bottom of the car. There are limiters, so use them.

Btw thanks somebody for rating a 10!!
I could've put PGWheels (soft tires) on it but that would not show how nice the suspension is. Try it!

It's also a new kind of suspension, with 2 springs per wheel, each doing different things. Look at the values, one it pushing out, one it pulling in.

To add to your car just delete the black circles and replace them with your wheels, and :hinge your wheels to the grey bar, NOT THE GREEN CIRCLE!