Ever since I went from a 245/50 to a 275/40 tire, the car will pull firmly to one side or the other when changing lanes and going over very slight grooves or raised places in the center of the highway.
You have to be holding on to the steering wheel pretty firmly.

My '99 WS6 has this wheel size on it stock and it does not do this so I'm thinking it may be some other issue...
On flat pavement cruising it does not pull at all to either side, can go for 20 seconds easy without touching the wheel...just don't ease over to where the pavement is slighly raised or lowered under a tire...
Maybe the toe in or something on the alignment??

 

Tires
Some brand/model of tires are just bad at tracking road imperfections, I had some Pirelli Pzero Rosso Asimmetrico tires that were really bad at doing that.
I bet if you swap your front wheels/tires from you 99TA it'll be gone.

 

Tires are a huge factor, and so is alignment.

 

My '97 WS6 tracks pretty badly with the 275s with Nitto tires on bad roads. Some is tires, some is just the side-effect of a 10"+ wide tire.

 

What model of Nittos? About to get some new tires and just got a set of Nittos on the rear.

They are Dunlop SP8000's on there now I believe thats the number..
I've had it aligned twice since these tires were installed...Hopefully it is just the tires...may try swapping the tires from the WS6 and see what happens, thanks for the idea.

 

That should tell you right away. Post back with the outcome and what tires are on the '99.

 

The 555's don't remember the suffix though; but the not the DRs. These were on factory 17" WS6 rims.

I also had a pretty "aggressive" alignment on it too though, so I'm sure that didn't help.

 

Will do, my be the w/e before I have time...the 99 has the original factory Goodyears on it still

 

They have 555R II Extreme that has a huge tread on the outside edges very similar to the Dunlops I have.. maybe that's some of the reason it pulls.
And then they have a 555 Extreme Performance which is what I just got for the rears that have smaller treads / nobbies on the edge. I have 315s on the rear and 275's up front...and the ones on the rear now ride a whole lot smoother than the Dunlops did.

 

Put the '99 wheels on it and drove it around for about an hour, barely a single pull to either side, so it is the tires, about time for some new ones on the front anyway, but its pulled since these were new..
Here's was the mismatched looked...not quite the look I would be looking for...but I guess its kind of patriotic....red, white, and blue

 

I have Dunlop Direzzas in a 275 and they pull the car around a little also. other than that they are a great tire.

 

I have 275 goodyear GSD3's on the front, and they pull pretty bad. But, so did my crappy stock 245's on my car. I aligned mine at work and just did a normal daily driver alignment and didn't help. Maybe the roads around my place are just old and grooved. I have learned to never take my hands off the wheel. haha

 

Just curious on the back spacing on the front rims, sometimes if you go with a spacing that put the tire closer to the edge of the fender it can track poorly

 

I believe when I ordered them I specified the same exact back spacing as the stock '99 WS6 rims since I was planning to use the same size tire. Also, I have the LS1 spindles with the LS1 brake conversion on the '95 if that matters.

Ok, I did have the paper work here...says on there 17X9 5-4.75 ...seems like the 4.75 is the back spacing, can't remember, was 5 years ago when I looked all that up....no on second thought, thats the darn bolt pattern.....doesn't appear that the BS is specified on the sales sheet.

 

Correct.