What's the noun for tricyclic? Here's the word you're looking for.
tricycle
A cycle with three wheels, powered by pedals and usually intended for young children.
(Philippines) cycle rickshaw (a motorized three-wheeler, the Philippine version of the rickshaw, consisting of a motorbike attached to a sidecar which may be customised according to the owner’s choice. Widely used as a public means of transportation alongside the more popular Philippine jeepney).
“She is a keen tricyclist, and will happily ride a few blocks in this way.”
“If you make the distance 100 feet, the tricyclist will probably win!”
“There will be joined by aerial performer and contortionist Rosie Cheeks, prima ballerina Madame Galina and female clown and tricyclist Jessica Arpin.”