In Sonic Riders, the Rengoku can be seen advertised on a sign in the intro cutscene. However, it does not appear in actual gameplay.
Sonic Speed Simulator
The Rengoku appears in Sonic Speed Simulator as an Extreme Gear of the "Exotic" Rarity. it was obtainable 3 times: The first time, it was obtainable by buying it for 300 robux. The second time, it was obtainable by buying it for 49 robux. The third time it was obtainable by getting to tier 14 on the premium track during "Fast Pass" Season 5. After acquiring it, the player can equip it in levels, and perform Hoverboard Boosts and tricks while riding it.
Trivia
The Rengoku resembles the Type-J only recolored red and white (despite the Type-J being a Babylon Standard exclusively for Jet).
As the Rengoku is not a ridable board in Sonic Riders, its statistics are unknown and the information on the advertisement is illegible.
In Sonic Speed Simulator, some of the text on the board can be read, although the majority of lines on it are repeated several times, and do not accurately reflect the text seen on the original advertisement in Sonic Riders.
