At 2:05 AM -0700 12/22/99, Tim wrote:
>Here's one I haven't seen...why did MG decide on a unibody versus a
>I'm sorry if this is one of those "obvious things that every MG owner
>should know", but I just thought it would be alot easier to do the body
>work (sills) if it weren't structural.
My understanding is that it has to do with cost and a lot to do with
rigidity and weight, and therefore gas mileage, required engine size
/ performance, etc. A ladder chassis is not nearly as stiff, at
least not until it gets heavy (apologies to Triumph owners). And,I
imagine, panel fit was faster and cheaper when everything was welded
in a jig on the assembly line rather than fitted and bolted.
As for alternatives, space frames are really expensive to make and
repair; the backbone chassis creates a large central hump which isn't
great for passenger cars.
Unit bodies didn't really get popular until the advent of independent
front suspension--e.g. Morris Minor, Magnette ZA, and Mini. Rigidity
prevents"cowl shake" on roadsters like the MGB--a good thing.
Morgans are famed for using the light weight chassis as a flexible
member of the suspension, and Daimler Darts were famous early on for
the doors flying open as the chassis flexed. Early attempts to use
unit bodies on mass produced 4x4s (American Motors?) were criticized
because some weren't rigid enough, and would bend and deform over
rough terrain, doing things like preventing doors from opening.
'84 Alfa Romeo GTV-6