Motorcycle chassis

A motorcycle frame includes the head tube that holds the front fork and allows it to pivot. Some motorcycles include the engine as a load-bearing (or stressed) member; this has been used all through motorcycle history but is now becoming more common. The rear suspension being an integral component in the design. Frames have been made from titanium, aluminium, magnesium, steel and carbon-fiber along with a combination of these materials.

Frame Materials

Steel

Examples

Norton Featherbed frame Early Honda CBR600

Aluminium

Examples

Honda VFR750

Aluminium and carbon-fibre

Examples

Bimota SB8K (composed of two aluminium alloy beams and carbon fibre plates)

Carbon Fibre

Bimota TESI 3D

Titanium

Examples

1971 Titanium Husqvarna

Magnesium

Examples

Elfr 1986

Magnesium and Aluminium

Examples

Aprilia ETV 1000 Caponord (aluminium alloy welded on to aluminium-magnesium alloy castings)

Frame Types

Pressed frame

The frame is mass-produced by sheet metal pressed or stamped into shape. Typically a single-cradle structure is used.

Examples

Single cradle

The motorcycle engine is held in a single cradle with a single spine.

Half-duplex cradle frame

The motorcycle engine is held in a double cradle with a single spine and single downtube.

Examples

(Full) duplex cradle frame

The motorcycle engine is held in a full by two separate cradles, normally with a single spine.

Examples

Double cradle or perimeter frame

Two cradles follow the perimeter

Examples

Spine or backbone frame

The motorcycle engine is suspended from a single spine.

Examples

Honda CD200-T Benly
Lots of (new) Triumphs.

Beam

Twin beams join headstock to swingarm pivot in as straight and short a line as possible.

Examples

Monocoque

Supports structural load using the external skin of the frame.

Examples

Honda NR500

Trellis

Similar to the beam frame, connecting the steering head and swingarm pivot point directly as possible. The frame is made up of a large number of short steel (or aluminium) tubes welded together to form a trellis.

Examples