The Backward loop, or Back loop is arguably the best loop for all scenarios due to it's flexibility and power gain.
Hold the Space Bar and the Down Arrow. To successfully do this stunt, hold the button for longer than 1.5 second. In Radical One's case, it takes only 0.5 second for a loop. With Nimi, it only takes about 500 milliseconds, about the same as Radical.
The stunt usually sends the user up high, the further the Axis of Rotation the higher. It is great for evading stronger cars and/or surprise an unsuspecting enemy. The tactic can be used to let the enemy go first then Creep Up on them, but this is hard to master, and is risky. This stunt results in 16-22% gained after.
Almost every car can do a Backward loop. More flexible cars such as Radical One, Kool Kat, and Tornado Shark can do many off merely a Speedbump, and can do Massive amounts over Giant Ramp. Note: MASHEEN cannot do it properly, unless he does it off a Giant Ramp.