It's quite an old photo, but it’s tied to an achievement I haven’t been able to come close to since.
It was made for a photo competition organized by a company that manufactured spoke lights.
It took three people to create it:
A photographer, a cyclist, and a person dressed completely in black who spun the ignited steel wool.
We used four flashes: one behind the cyclist, one front right, one front left. The fourth was needed to make them flash when the cyclist was in mid-air—meaning neither on the first nor the rear curtain. The flashes were removed during post-processing.
The process of the shoot:
An exposure of about 8–10 seconds, quick ignition and spinning of the steel wool, then running out of the frame, while the cyclist was already speeding in and jumping.
The strange light pattern seen at the bike's wheel is the base version of the spoke light made by the company that announced the competition.
Luckily, three attempts were enough, and we didn’t need the fire extinguisher we had prepared.
The photo won the grand prize of the photo contest: the company’s top-tier spoke light!