Bias ply absolutely change shape at speed and temp. Radials, not so much. They are very stable in their dimensions. Do radials flex around some, sure. This is why they tolerate a wider range of angles before showing abnormal wear but that is compliance, not deformation. Which is why more serious performance will require temp checks to see what do teh tires need.

Old trick in my oval track bias ply days was to pump up a tire to about 60 psi and leave it in the sun for a week. This produced a larger diameter tire that we used on outside positions. When we changed over to radials that trick no longer worked. We could not get the radials to stretch the same way that bias ply did. Flat out didn't work.