Crossmember
（重定向自Crossmembers）
A crossmember is a structural section, usually of steel, usually boxed, that is bolted across the underside of a monocoque / unibody motor vehicle, to support the internal combustion engine and / or transmission. For the suspension of any car to operate as it should, for proper handling, and to keep the body panels in alignment, the frame has to be strong enough to cope with the loads applied to it. It must not deflect, and it has to have enough torsional strength to resist twisting.