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Also the Body itself was bolted in various places to the frame with the view of giving support where required. Though being a convertible rigidity was limited.

So it is easy to follow the path from the original type Ladder frame to a stronger and less flexible frame designed for the early TR Triumphs. When we move onto the TR4 frame the outside rails were moved outwards in order to maximize the effect the body had on stabilizing the frame. This makes it very close to being a Perimeter Frame. Used by GM in their full sized sedans.