Tires: change to new tires size, toyota tacoma 4x4, p275

Question
Can I change tires size from P285/R20 to P275/R20 or P265/R20 on 2006 Toyota Tacoma 4x4?

Answer
Melissa,

When it comes to tire sizing, you have to be careful.  

There are 3 numbers in a tire size and they all are important.  For example, Tire Rack says that you vehicle should have a 265/50R20 as a plus size.  They do not say a 265/55R20 will fit, and it is clear that a 265/45R20 is too small.