lateral stability problem
 

I upgraded my base '12 to 19x9.5 front & 19x11 rear wheels with 255 35 front tires & 305 30 rear tires. At speeds above 40 I notice a great deal of lateral movement. I have work to keep the car straight. It feels like I am riding on marshmellows, really spongy from side to side.. The tire pressure is @ 50psi. Anyone experience this after going with bigger setup?

That is a really high tire pressure for one thing. Lower your pressure to 35 and then take it for a ride. Also if you have brand new tire it takes a while to wear the mold release off the tires.

Then let us know how it feels. Also what tires did you buy?

I bet it is the tires. What kind of tires did you get??

:iagree:

Hankook v12

Usually you increase pressure to reduce lateral roll, but I''ll take your advice and lowerthepressure to 35.
Thanks for the response, I'll update in a few days

50 psi cold? Thats way too high. When they get warm thy must be hitting 60 or so. That's dangerous. I run 36 all around on my PSS tires. That's cold pressure.

50 psi is way too high. You stiffened the crap out of the tire and reduced the contact patch. No wonder your car has a lateral stability problem. Over-inflation can provide crisper turn-in and handling to a point but you've over done it.

As stated above, you have reduced your contact patch. Found this online.

http://static.ddmcdn.com/gif/tire-problems.jpg

50psi.??I put 40 psi,all my friends[even tyre shop] already said i am crazy.!

It's possible 40 works and would be helpful at an autocross, i'm not sure why it would be needed crusing the streets. Over inflation can happen with as little as 2 psi.

Initially the tires had 40psi. Max inflation for that tire is 50psi.

Where did you get the PSI number from? Why did you decide on that?

Its fine. Its just the new tires having break free grease from the mold still on them. That combined with the higher tread depth (which will allow more tread flex (will give a more spongy feel at first. Give it a couple hundred miles and it will go back to like it was. I had the same issue and is definitely an odd feeling

http://www.the370z.com/wheels-tires/...re-change.html

Red, typically to stiffen up tires, you add pressure. The tires are rated to 50psi. In this case it made the problem worse. I did what others mentioned and dropped the pressure. I'm at 31 psi and it made all the difference. Thanks for the good advice