My car pulls to the right sometimes and sometimes it pulls to the left. Sometimes it goes completly straight. It started doing this after I put on rota gt3's, with 195-50-15 tires.

 

Yeah, I need to get them balanced.

 

You should probably do that.

 

get an alignment

 

if you changed the offset at all with the new wheels that can make it easier for the road to pull your wheels off track...just add a bit of toe in...just a smidge, and you should be good...
same thing happened when i put my wheels spacers on...

 

Running with any camber? Negative camber will make it pull in a direction if it hits the road right.

 

The car has a omni sport camber kit and the wheels are almost straight up and down in the front, small amount of camber in the back. The car went completely straight when I had the donut wheels on it.

 

Sound like it's an offset change or alignment problem then.