Vague on-center steering feel - Kumho Ecsta 712

[?]

Greetings all. I recently installed 205-50/15 Kumho Ecsta Supra 712 tires on my
'91 SE-R. These replaced well-worn Pirelli p700z tires. My alignment settings
are: (front) -2.5 camber, 2.0 caster, 0 toe; (rear) -1.1 camber, 1/16" toe out.
Tire pressures are 32f, 30r.

I have a couple hundred miles on these tires and have an uncomfortable, vague
on-center steering feel to these tires. Going in a straight line, the car wants
to wander a bit from side to side - like 1/2" or so, subtle but real &
absolutely noticeable. Which side pulls is not consistent. It's almost like a
momentary, slow pull. This happens regardless of the road and/or road surface,
but is more pronounced and noticeable on poor roads.

For a few days, I thought it was me and/or my car. However, today I found that a
friend, who drives a Volvo 850 T5R with 16" Kumhos, has exactly the same
problem. The only common thread between these two issues is we both bought from
Tire Rack. I don't think Tire Rack has anything to do with it per se, but maybe
a bad batch of tires made it to them...?

I've done searches on the web, USENET, list archives, SR20DEforum, etc. and
turned up nothing about this. Anyone here have any experience, ideas, and/or
comments?

Carson M. Hanrahan                        '91 Classic w/the usual stuff
"It is better to go into a corner slow and come out fast than to go
into a corner fast and come out dead" - Stirling Moss