I just got a 350Z touring used and it has new tires on it.
At high speed it feel smooth, but on the side road between 30 - 40
it feel like it bouncing. My 91 300ZX on the same road was nice riding but firm, but this Z it stiff and harsh. Is this normal ? or is something wrong with the car ?

 

Welcome. The 350Z ride is what it is. Some tires are more comfortable than others. For comfort ratings check Consumer Reports.

 

Do you know if the car had any suspension mods done?

 

I am checking on that tonight.

 

The 90's 300Z was more of a step back to GT cars and touring. With the 350 we're back on track to true sports car and less of a touring car.

 

I did find that they put 48lbs air in the tires. I move them down to 34 and that help a lot. And about the 300ZX being more of a touring/GT and the 350z is more of a touring/sport car tell me why the ride is harsher than the 300zx.

 

my ride was actually a lot less harsh when i put my tananbe gf210 springs on and 19's...sounds nuts..but true.

 

That would make any tire hard as a rock.

 

Is your car a 03/04 or a 04.5+? The 03/04 car's use oem shocks with a lot of compression dampning and not enough rebound control, very well known by their owner's to have bounce and freeway porposing.

 

i replaced the oem shocks with Tokico struts...harsh/bouncing ride no more.