Tires: Tire dimension, tire dimension, endurance test

Question
Hello,
I have a question on tire dimension. Does PCI have an influence on  degree of tire expanding after endurance test or in service ? And then why they are bigger? If a tire after endurance test is cooled down to room temperature naturally, and its inside pressure is adjusted to the initial pressure , then a measurement is made, the result is the overall diameter is a little smaller than that before the test. Does it affect to tire performance in service ?
Thank you very much for your reply.

Answer
Ngoc,

First you have to remember that tires expand not only radially, but laterally as well.

So the first question you asked was about PCI (Post Cure Inflation) influencing how much a tire expands in service - and the answer yes, PCI does influence this.

Then you made you made a statement that when tires are tested, that they are smaller in diameter than before the test.  But what about the width?  Did the width increase?

BTW, it is important that you distinguish between bias ply (Cross ply) tires and radial tires as they behave differently.

So before I continue, let's get those questions out of the way.  Plus, it has been a long time since I observed the dimensions of tires before and after testing.  I am going to have to think about my experiences and, perhaps, consult with some folks who are currently doing this kind of work.