Used tires which are alternative to new ones should be bought with caution to ensure safety. They are to be properly inspected to certify them safe for use before purchase.
Tires that suffered deformation & wobbling are dangerous because they don't usually wear evenly. They have spots that wear rapidly & likely cause tire blowout.
Car users want to adjust ride height by changing to tire with different diameter. You can calculate the diameter yourself without using tire size calculators.