The Fly Wheels is an obstacle, firstly introduced on American Ninja Warrior 8, as the third obstacle in Indianapolis.
Competitors must swing across 3 hanging wheels, with a one inch ledge on either side. The second wheel was placed higher than the other two wheels, so competitors would have to make sure their momentum got them high enough to grab onto the small ledge on the second wheel. After the second wheel, competitors would have to maneuver their way onto the third wheel, which was on a pendulum and therefore would swing back and forth, but the wheel itself did not spin. And finally, competitors must make a dismount to the landing platform to advance.
This obstacle was proven to be difficult, as numerous competitors who attempted it, failed to swing their away across, typically due to weak momentum. There was also a slight disadvantage with its placement after the Rolling Log, in which some competitors may have fell due to dizziness and/or lack of focus. A total of 25 competitors fell on this obstacle during Indianapolis qualifiers.
During Indianapolis finals, the third wheel was removed, creating a far longer dismount. Three competitors consequently failed on this obstacle.
The Fly Wheels returned on American Ninja Warrior 9, as the third obstacle in Los Angeles, with a similar specification from the previous season, with the third wheel was removed during Los Angeles finals (just like during Indianapolis finals). During Los Angeles qualifiers, 20 competitors failed on this obstacle, including Chris Workman. However, no competitor failed on this obstacle during Los Angeles finals.
During Celebrity Ninja Warrior: Red Nose Day, the obstacle featured 3 wheels, with shorter gaps between the wheels and all three wheels were placed on the same height, in order to make the obstacle easier for celebrity competitors. Among the 4 out of 9 celebrity competitors who attempted the obstacle, 3 of them (Nick Swisher, Ashton Eaton, and Stephen Amell) completed the obstacle on their first try, while Derek Hough failed on his first try, but trying again and successfully completing the obstacle on his second try.
On American Ninja Warrior 10, the Fly Wheels appeared as the second obstacle during Miami qualifiiers, with the gap between each wheel was increased by few inches, requiring the competitors to build a bigger swing and momentum. Also, the wheels were arranged in a slight decline, in similar fashion to the Cannonball Alley.
Due to its placement as the second obstacle, more competitors attempted the obstacle than during American Ninja Warrior 8's Indianapolis qualifiers and American Ninja Warrior 9's Los Angeles qualifiers. Despite that, similar to during American Ninja Warrior 8's Indianapolis qualifiers, 25 competitors fell on this obstacle during Miami qualifiers.
Later on the same season, the Fly Wheels reappeared as the second obstacle during Indianapolis finals, replacing the Cannonball Drop during Indianapolis qualifiers. The obstacle also swapped place with the Cannonball Drop, which replaced the Fly Wheels during Miami finals. Coincidentally, both the Fly Wheels and Cannonball Drop were used in Los Angeles course on the previous season. With the obstacle appeared during Indianapolis finals, this marked its return to Indianapolis course, since its introduction as the third obstacle on American Ninja Warrior 8.
Australian Ninja Warrior
On Australian Ninja Warrior, the Fly Wheels appeared as the fifth obstacle in Semifinal 3, and was called as the Big Wheel.
Ninja Warrior UK
On Ninja Warrior UK 4, the Fly Wheels appeared as the fourth obstacle during the finals' Stage 1. However, the obstacle featured just 2 wheels (similar to the one used during American Ninja Warrior 8's Indianapolis finals and American Ninja Warrior 9's Los Angeles finals) and no trampoline at the start, with the pendulum wheel was placed as the second wheel.
- Compared to most qualifying cities, the Fly Wheels is an upper-body obstacle despite being as the third obstacle. The upper-body and lower-body (balance) obstacle between the third and fourth obstacle were switched in Indianapolis qualifying course on American Ninja Warrior 8, as the Disk Runner is a lower-body (balance) obstacle. This deviation will eventually continue on American Ninja Warrior 9 and American Ninja Warrior 10.
- This obstacle is also one of the few obstacles, where bending the arms at a 90-degree angle is not recommended. In this case, putting the arms straight on this obstacle will give competitors more momentum to swing to the next wheel.
- On several Ninja Warrior's international formats (e.g. Ninja Warrior UK 3 and Australian Ninja Warrior), the third wheel (the pendulum wheel) of this obstacle was combined with the cargo net, with a trampoline at the starting platform. Therefore, competitors must jump from the trampoline and grabbed the pendulum wheel. Then, competitors must build enough swing and momentum to make the transition to the cargo net, and finally reached the landing platform to advance.