I have 225/50/16 kuhmo supras.
Max pressure is 44lbs

Initially I had 31 in the front and 36 in the rear.
I had some shakes and vibrations at highway speeds.

I increased the front and rear to 36/39.
The shakes are minimized, but I had better handling with 31/36.

-Greg

 

Your vibrations are caused by something out of balance, not tire pressure.

Your also running the front/rear ratios wrong. You should be a bit higher in the front then the rear. Your the other way around. Our cars are much heavier in the front, thats why Nissan, and most any other FWD car will have slightly higher pressure up front.

I believe the correct cold tire pressure for your car is 33 front and 29 rear. You can run slightly higher, but keep in mind the higher you go, although you feel tighter steering response, your actually reducing the tires footprint. When you reduce the footprint, you lose traction.

 

You might have a tire that has a flat spot or is not perfectly round, if you can isolate the vibration to a tire or tires I would go to a good tire shop and have them trued. They use a special cutter to make a tire perfectly round, theory is that the milage lost do to trimming is more than made up for due to drcreased rolling resistance when the tire is perfectly round. Try it, you'll be amazed at the difference it makes.

 

doesnt it say 32 in front and 34 in rear in the manual?

 

True, you will lose traction in a straight line launch. However, your traction in turns will improve. The higher pressure means the tire deforms less under lateral loads. This keeps more of the tread on the pavement in turns.

The higher pressure in the front gives you a little better traction in the front than the rear. This reduces understeer.

 

more in the front?, ok I try it out.. 36/33 I'm thinking.