Want to know which one is your next step up? I made this handy table.
All the possible combinations with 44-56 chainrings and cogs from 12 thru 18.
I have one printed and I circled the gear combinations I use.
50x15 for most trainings and 48x14 for racing (333m track)
I like it because I can see the equivalences and overlaps of the gears.
Also, look on the table to the right for the exact nominal gear inch ratio.
Here is the table with higher resolution:
https://www.dropbox.com/s/k5mlbzj8im...n2016.png?dl=0
Compact Version (48-52 x 13-16):
https://www.dropbox.com/s/hl3timxrcf...mpact.png?dl=0