Originally Posted by lordromanov01
How can I set custom ringtones on a Nexus 5 (not rooted)?
There's no option just to set an MP3 file as one.
If you install some sort of file explorer (like ES File Explorer) then you should be able to set one when it asks you which app to use to select the ringtone.
Aside from that, if you copy/paste files to the Nexus after plugging in the USB cable and having the Nexus set up as an MTP, that usually works as long as you put the files into the Ringtone or Notifications folder.