SSX

This is a pretty straight forward achievement, first you must complete the "Team SSX" achievement in the World Tour:

Once you have done this enter the Explore mode and earn a bronze medal or better in a Race event with all nine members of "Team SSX" who are listed below;

Zoe
Elise
Mac
Alex
Tane
Kaori
Psymon
Moby
Ty

There are several short, easy drop points that are well suited to this achievement;

'Fast Forward' on the Makalu peak in the Himalayas
'Broken Pass' on the Vorassay peak in the Alps
'Diamond Back' on the Boris peak in Siberia (suggested by koobz2142)

If this solution can be improved please comment.

You must first unlock all members of Team SSX (which unlocks the "Team SSX" achievement). Once you do this, go into Explore and compete in a Race It! Event with each member and earn at least a Bronze. A Gold or Silver will also count towards the achievement. An easy run for this would be Curnoe's Mustache which is located on Whitehorn Mountain in the Rockies. You do not have to worry about dying on this drop and being forced to use rewinds which inflate your time.

To more easily keep track of the riders with which you have earned a Bronze, start with Zoe and then proceed down the line to the right on the character select screen. Also, neither Griff nor Eddie count towards this achievement, as they are not part of Team SSX. This also holds true for anything the specifically mentions "Team SSX" in the requirements.

If I can do anything to improve this solution, please leave a comment explaining.