MR. APPEL defines a frameless car as one in which the body is used as a structural member and in which the axles, engine, and steering gear are attached to the body, instead of having that unit used merely as a shell for passengers.
The chief differences between frameless and conventional cars are summarized by stating that frameless cars: 1. weigh about 2% less; 2. cost less by somewhat more than 2% - where sufficient quantities are involved; 3. are definitely more rigid; 4. are necessary to obtain the lowest floor height; 5. cost no more to service; 6. are just as quiet on the road; and 7. do not involve higher insurance rates than conventional cars.
Design effects brought by the frameless construction are listed as including: 1. elimination of the outside coach builder, even in Europe; 2. there can be no shifting of blame between body and chassis designers for body squeaks, rattles, and so on - the body and the chassis engineer become the same person; 3. because spring brackets, shock absorbers, bumpers, front frame extensions, and so on, are attached directly to thin sheet metal, particular care must be taken in providing local reinforcements to distribute the stress; 4. considerably greater rigidity in the underbody is required for convertible models.