So you also want to remove any ID3v2 tags (there are no v3 tags), correct?* If so:
Go to Options (F8) > Tags > Mpeg.
Set the Read options so that the following are checked:
- APEv2 (optional, but recommended)
Set the Write optiosn so that only the following is checked:
Set the Remove options so that the following are checked:
Then load your files, highlight them and
- Press the Save button. This will create ID3v1 tags where they were missing and copy ID3v2 data to them.
- Press the 'Remove tag' button (red X). This will delete the ID3v2 (and APEv2) tag.
Or Ctrl+S, Ctrl+R.
* If you want to KEEP your ID3v2 tags, it's a totally different setup in the options. It's important to know which you want to do before you start, because you will lose data from the above procedure. You will lose any extended fields such as Composer, Album Artist, ReplayGain and many others, because ID3v1 only supports very few fields. You will also have track titles truncated because ID3v1 supports a maximum of 30 characters in titles and album and artist names.
If keeping any of that data is important to you, such as for use on your home computer audio system, I would recommend copying the whole library and maintaining a separate library with only ID3v1 tags to be used on your car player. Your next car player won't be as dumb.