Google Product Forums
Re: How do I sync multiple calendars to my iPhone calendar?
Giaochino May 5, 2012 2:50 PM
Posted in group: Google Mobile Help Forum

Categories: Apple Devices : Other Google Products :

https://www.google.com/calendar/iphoneselect  didn't work for me though.
I finally got it done by changing the language settings in m.google.com and then go to  m.google.com/sync
Thanks for the inspiration anyway!