Tire pressure: ride quality vs. vibration ?

[megerian]

I have been trying to find the optimal tire pressure for my 88 turbo look. There are plenty of threads about the ideal tire pressure, so I went with that advice.

My issue is that my recent change to 29/35 ( from about 31/36 ) seems to have had the desired effect of having a slightly smoother ride in town, less violent bumps, less bump steer, etc. BUT (and this might be unrelated or even my imagination) I think I have a little bit of vibration at high speed that I did not have before.

I had a good Porsche shop do a high speed tire balance and they said it was fine.

So the question is, could the lower tire pressure possibly cause a slight vibration at high speed?

[darrin]

I find that my front tires feed a bit of vibration back to my steering wheel after sitting for a while. Could be that your lower pressures are causing bigger flat spots to develop while sitting. Mine smooth out after a few miles, do yours?

[RWebb]

use 30/32

[megerian]

Prior to the pressure change, I would get a bit of vibration, then it would go away completely after the tires warmed up.

Recently, it seems like the vibration reduces, but there is still some vibration at high speed that does not go away completely even after the tires have warmed up. I was trying to find out if this could be related to the tire pressure.

[Discseven]

Off the subject of vibration, I've found running 3 lbs less than manufacturers recommended pressure makes tires last longer --- they don't wear out in the center. Slightly more spongy handling but I'd rather have the tires last longer.