Since the original thread isnt open for replies ill ask here. As announced by @Alex Hodgkinson in this thread https://forum.sector3studios.com/index.php?threads/tyre-models-versions-and-what-they-mean.16071/ quite a number of cars will receive the v4.1 tires with the upcoming patch. Is it recommended that you delete all old setups for those cars or are the changes (at least from v4 to v4.1) not that drastic?
Yes definitely recommended. While most cars do not have any single drastic changes made to them, the sum of the many small changes adds up to something quite big so it's best to start again.