Having replicated the complex internal system of the Great Wyrm by way of Archanical contraptions, the Great Warlock was able to process its Black Bile into the buoyant gas which granted the massive creature its wingless flight. This technology became known as ‘Barrel tech’ on account of the rejigged barrels incorporated to contain the gas and was soon put to use in various sky-faring vessels. The smaller the vessel, the faster it could go and the less gas it required to stay airborne. This led to the design of the speedy Barrel Bikes, Allowing the Barrel Riders to protect the larger Archanical Airships of the Sky-Fleet. Most commonly they can be found flanking the Archanical Barges as they ferry goods between Wollockshire and the Dwarven holds of the nearby mountains, protecting them from the opportunistic Sky-Pirates in the high valleys.
The Barrel Bikes are a great way to add a bit of technology to your D&D games without it looking too out of place and futuristic. They are also a great force-multiplier for the Barrel Riders and Barrel Rider Captain, allowing them to swoop in close, unload some shots from their Halfling Blunderbusses, and get out again without prompting attacks of opportunity.
Here is the link for the Barrel Bikes.
these are draft profiles for the Reign of Arcane: Rise of the Halflings module, and the final profile may differ from what is displayed here.