As far as I can tell, the gear tracking functionality is limited and I would like to propose some enhancements for your list of feature requests:
1. Offer more options in the "New activities" checkbox. The full list of Activity Type should be available. I have a pair of shoes I normally use for trail running and another for street running. With more activity types, I could have more default gear automatically calculate mileage.
2. Allow for more than one gear item per gear type. For example, I would like to track the wear on my bike's brake pads, tires and chain. If I change my chain, for example, I cannot add another instance of bike gear to track the mileage of my new chain and continue tracking the mileage on my brake pads.
Thanks,
Hugues