soft sidewalls

[JdotYang]

i was doing some research and noticed a lot of people talking about the side walls on their tires. How do you tell or feel when a sidewall is too soft when driving?

I've also noticed some rust on the rotor, mainly on the bottom portion. It looks like the silver painted part is rusting. Is that normal?

[fastkevin]

Soft sidewalls tend to squish when pushed, sometimes giving the impression that the car's lost traction. They obviously will create more roll as well. Their up-side is that they're more shock-absorbent, meaning a more comfortable ride on the street. Good for soft ride, bad for getting feedback and feel on the track.
I'm unaware of anywhere on the rotor that's painted. You can imagine if it did have paint on it, you would lose a lot of braking force. At least until the pads scrubbed it all off. Surface rust is fairly normal on the rotor surface (unpainted) however, and will accumulate somewhat quickly if the car stays stationary for any length of time. It's cleaned off when you apply the brakes while driving.

[JdotYang]

thanks fastkevin

[Don Nguyen]

It's just like telling if a suspension is soft or stiff. Obviously, the changes might not be as obvious, but if you are pretty familiar with your car, you'd be able to tell.

[abu]

You are usually comparing to another set of tires when saying this tire has soft or hard sidewalls. this comes from trying different brand or model of tires. Some Rust on the rotors are normal