Why don’t bikes have a collective noun? Crows have a murder, geese have a gaggle, and heck- rattlesnakes even have a rhumba! So why not bikes?
So, here are my suggestions:
A horde: V-twins and other Harley style bikes. A horde of bikes carried their doctor and lawyer riders to the convention.
A scream: Street bikes. A scream of bikes raced down the street carrying their beautifully matched riders.
A ride: Touring bikes. A ride of bikes stopped at the Geritol museum.
An annoyance: Dirt bikes. An annoyance of bikes road down the walking path.
A roar: a mixed group of bikes. A roar of bikes paraded through the streets during the rally.
A dystopia: Adventure bikes. A dystopia of bikes took the mud track through the war ravaged countryside because it looked ‘more interesting’.
Yes, I do happen to spend most of my time riding alone and have copious amounts of time to contemplate my navel- why do you ask?