Assigning default gear for individual activities

I just bought a pair of trail running shoes in addition to my road running shoes. I'd like to set up Garmin Connect such that when I choose 'run' on my Fenix 3, my road running shoes are linked and when I choose 'trail run' it knows that I'll be using the trail running shoes.

Currently I can only select 'other' when I choose an activity assigned to my trail running shoes, 'trail running' is not listed as an option under gear settings.

I have the same problem with my road and mountain bike.