Car is pulling to right after the new PS2 went on.
Checked tire pressures.
Do I need realignment?
Didn't pull before new tires.

Wonder if swapping left-right will help.

I'm also feeling more understeer than with old pzeros now.

Hmmm were the balanced correctly and/or did one of the weights come off? Sure, if they're new try swapping them and see if it pulls the other way... I know PS2s are way grippier than the Pzerors and I'm not sure if you changed your alignment either? I take it you kept stock sizes too?

It may be tramlining. Make sure the road you test them on is perfectly flat with no ruts. Some tires tend to follow ruts in the road and pull the car that way. Also try the far left lane and see if it pulls left.

Remember that new tires take a while to come to full grip... any tire will be somewhat slippery for the first 500 miles or so.

The PS2 should not tramline. That's one of the reasons they are not as directional as the last version. A directional tire will tramline on accasion, an asymetrical tire should not....

As far as understeer, remember your last tires were more worn and you were getting less "squirm" from the treadblocks. A full tread depth tire will understeer slightly more than a worn one. Plus the tire still has mold-release on it. Re-evaluate after about 350 miles and see if they feel better. They should.

kept stock size and no change in alignment.
~350 miles so far. pulls on smooth flat road on left or middle/right lane.
i'll try flipping and see if it pulls the other way.
i assume all i need to flip are the front ones?

Dumb question but are you sure your tire pressures are all correct i.e. left vs right

first thing i checked were pressures
the installer had all the wrong pressures and uneven left-right.

i put in the default 36/44.

Try lowering your pressures to 33/39 cold... should help understeer

Not that it helps but I just recently put on PS2s and the car drives straight as an arrow. We did do an alignment just for kicks. Maybe yours is slightly out of wack and the new rubber and/or wider tires etc. are making it more noticeable?

I set it to 36.5/39 cold. That cured the understeer.
Now the car is handling beautifully around corners. Nice and neutral. I can attack with confidence.

The slight pull is still there, even when I drive on the wrong side of the street. Will get an alignment. It's been a long time anyways.

Make sure your corner balance is 50/50 diagonally and that your caster is exactly the same side to side for starters