1998 chevy s10 pulls to left when driving and alignment question!!!?

I just bight a 98 chevy s10 v6 the truck is lowered and for some reason none of the tires are the same brand. I was looking at the tires for there max psi and the back said 35 and the front said 45 could I be getting this pull and rough ride from different sized tires? I think I'm going to get some tires from a junkyard and then get them balanced and then I'll get an alignment. But befor I do this does anyone have any other ideas why my truck pulls and wobbles abit.