Cradle Frame

A cradle frame is a motorcycle frame in which tubes run from the steering head down the front of the engine and back underneath it, so the engine sits in the frame like a baby in a cradle. A single cradle has one down tube that may split under the engine; a double cradle has two tubes all the way.

Cradle frames are simple and strong and were the standard design for decades. They are still widely used on cruisers, classic-style road bikes and many off-road bikes, while sports bikes mostly use aluminium perimeter or steel trellis frames, which are stiffer for their weight.

The lower rails also give some protection to the engine, which is useful off-road; a skid plate is usually mounted to them. After a crash, check frame tubes for bends and cracks, especially around the steering head and welds.