Rat bikes at the UK Rat and Survival Bike rally, 2005
Rat bikes are motorcycles that have fallen apart over time but been kept on the road and maintained for little or no cost by employing kludge fixes.Survival bikes look similar to but are different in purpose from rat bikes; they are modified for stylistic reasons.
Rat bike engineering: sound joint between sections of exhaust pipe without the use of welding equipment.
The concept of keeping a motorcycle in at least minimally operational condition without consideration for appearance has probably characterized motorcycle ownership since its earliest days. The essence of a rat bike is keeping a motorbike on the road for the maximum amount of time while spending as little as possible on it. This calls for adaptation of parts that were not designed to fit the model of bike in question. While the origin of the term rat bike is unclear, it may be attributable to custom motorbike magazines, and retrospectively applied. Most rat bikes are painted matte black but this is not a requirement.