A lot of iPhone users have problem syncing iPhone ringtones . Some questions are like "I can't sync ringtone to iPhone", "unable to sync ringtone to iPhone" and so on. Some are more detailed, such as: "it shows up as a ringtone in iTunes, but it won't sync to the phone. I've restarted my phone several times, hoping that would do it. I've removed all my ringtones, then re-synced them...but still nothing."
Well, if you ever encounter this kind of problems, the following methods will help you out, especially for Mac users.
Tips for sync iPhone Ringtone on Mac
First, make sure that:
Ringtones play in iTunes
All the ringtones are under 30 seconds
They do show up under sounds
They show up under the ringtones tab
They are in the ringtone section of iTunes under library
Second, if the ringtone is in iTunes and not appearing on your iPhone after a successful sync, make sure that none of the song fields (song name, artist, composer, etc) have special characters (like quotes, for example iPhone-Ringtone the"-" will cause the problem).
Third, The Length of your ringtone. Although they show up in the ringtones on your iPhone in iTunes after successfully syncing to your iPhone, they will not appear in the custom ringtones section on your iPhone if they are longer than 30 seconds.
P.S: For Mac users, if the problem still exists after answering all the questions above, you can use iPhone Ringtone Maker for Mac , which has a Ringtone Manager, to sync iPhone ringtone and make, manage your ringtones skipping using iTunes.
Ringtone Manager has 2 lists. All the ringtone files in the left list are those saved in your iTunes, and those in right one are your iPhone ringtones. Highlight any ringtone you need in any list, you can then transfer it between iTunes and iPhone. You can also delete or pre-listen to the ringtones.
If you have problem making custom iPhone ringtones for your iPhone, check: How to Make Custom iPhone Ringtone on Mac.