Chassis

The chassis of a motorcycle is the frame together with the parts that hold the bike on the road: front fork, swingarm, rear shock, steering head and wheels. The engine, bodywork and rider are carried by it.

Chassis design decides how a bike handles. Frame stiffness, geometry (rake, trail and wheelbase), weight distribution and suspension quality all affect stability, steering speed and feedback. Common frame types include the cradle, perimeter (twin-spar), trellis and backbone frames; on some bikes the engine itself is a stressed member of the chassis.

Many handling problems come from the chassis being out of adjustment rather than from the design: wrong tyre pressures, worn steering head or swingarm bearings, or suspension set for a different rider weight. Check these first.