Dozens of riders turned out for an evening of indoor roller racing in Bristol, UK.
Some 70 people registered for the event at Mud Dock cafe, which was organised in association with Iron Horse bikes and Rollapaluza.
Two cyclists at a time battled it out on a pair of vintage 1950s rollers connected to a huge dial.
Iron Horse brand manager Martin Astley said: "You really need to see a Rollapaluza to believe it - it's amazing!
"The sheer speed that can be reached on these things is incredible - watching some of the faster qualifiers, their legs were moving so fast they looked like Road Runner.
"The old wood floor of the Mud Dock cafe made for a thunderous rumbling when the riders got up to speed."
Qualification was a timed 500m sprint. The cut-off in the men's competition was 22.32 seconds. Fastest qualifier was Mud Dock mechanic Duncan Ferris, who used his 4X sprinting skills to net him a 20.04. In the women's, it was Sarah Barber who qualified fastest with a 24.51.
The top 16 men and four women proceeded to the knockout phase, where there were some close races. Ferris got his time down to 19.75 - pretty good considering multiple Olympic gold medallist Chris Hoy got a 19.44 when he did Rollapaluza.
By the end of the knockout stages there were just two riders left - Ferris and Marcus Mumford. For the finals, the distance was upted to 1000m.
Martin said: "Ferris shot into the lead in the early stages of the race and must have been 50m ahead at one point. Come 500m, though, and he was beginning to tire. Mumford had ridden a clever race and rode steady from start to finish. He caught Ferris at about the 700m mark and the two were neck-and-neck to the finish line, with Marcus just taking the win."
Mumford won an Iron Horse Transit and gold chain. Ferris got a T-shirt and bottle of wine. In the women's race it was Sarah Barber who took the win and a new Iron Horse bike.
Spectators crowd around the riders as their speeds are shown on a giant dial