The Tunnel Bike is a motorcycle and Bibleman's main source of transportation.
About the Bike
The tunnel bike is a motorcycle that only Bibleman uses, it is apparantley parked in or near a tunnel that leads to a series of tunnels that lead to numerous locations around the town. It apparantley has a tracking device in or on it,as in Breaking the Bonds of Disobedience after Bibleman goes through the full armor sequence he tells Cypher "Don't bother to track me."
It is first introduced in The Incredible Force of Joy, it is later seen as a different motorcycle in Breaking the Bonds of Disobedience. It is again seen in the beginning of Jesus Our Saviour part 2 as well as the purple armor for the last time. The silver version is revealed in A Light in the Darkness where it is revealed to be either a Harley-Davidson or a Victory motorcycle.
When Bibleman first uses the Tunnel bike with his new silver armor we see the bike is silver as well and that it has a Harley Davidson logo on the side.