Roll Cages for classic GT cars

 Problems often arise with these cars in finding a suitable way to attach the cage. There is little strength in the periphery of the body and the chassis may be much narrower. In these cases it may be necessary to make additional out riggers or sub fames to provide a secure mount for the cage.

	Typical installation of bespoke cage in Ferrari 250 short wheelbase. General view of driver's side. Front tubes pass through the top of the dash and then bend out slightly towards the side to be as close to the sills as possible.
	Back braces to main hoop pick up on rear shock absorber towers.
	General view of passenger side with diagonal and cross brace.
	Tubes mount to boxes tied into tubular chassis running through door sills.
	Different Ferrari, similar problems. Cage to FIA/MSA specs and removable. Wherever possible the cage is not seen from the outside.
	Cage bolts to sills as major strong point in tubular Ferrari chassis.
	Back braces pick up on strong point beneath rear window.
	Installation in TVR Grantura. Rear tubes braced to new sub-frame attached to original chassis.
	No suitable floor mounts so small mounting box fabricated which attaches to chassis under door sill
	Basic bolt-in cage for Lancia Appia
	Main loop with back braces to parcel shelf, diagonal bar and second loop above back window.
	Supports from parcel shelf down to chassis.
	Bottom of main loop bolts to mounting box built up around sill at b-pillar.
	AC Aceca, the requirement was for a fully bolt-in cage which would leave a standard interior for non-competition use.
	Front a-pillar tubes angled and bent to clear dash board. Plates at each end of the screen tube allow for its' removal.
	Main loop clear of wood framing in the roof. Plates at the end of the forward tubes allow for their removal.
	Back braces and diagonal to plates welded on the rear most chassis tube. Sleeve joints allow for removal of these parts of the cage.
	Marcos GT with combination wood and metal chassis. Main passenger compartment is based on a plywood structure with tubular metal sub-frames holding front and rear suspension.
	Much larger spreader plates than usual are supported with matching plates on the underside so the plywood is sandwiched between the two. Left picture is at the bottom of the a-pillar and the right at the back of the parcel shelf.
	Main loop with back braces welded to plates shown above. Full triangulation and a cross tube between plates.
	This Ferrari 308 was typical of older GTs with and substantial frame which formed a sound basis for the cage, which in turn added stiffness to the complete chassis.
	A full spec cage with equal protection for driver and passenger. main loop, roof X and door X's, main loop X and cross bar for seat belts.
	Main loop back brace (1), shoulder level back brace (2) and A pillar forward brace (3)are ....
	... tied into main chassis members/suspension pickup points
	TVR Griffith 400 for FIA Historic racing. Requirement for a fully bolt-in cage to allow body removal for final stages of construction.
	Wide angle view gives some distortion but shows triangulated main loop with triangulated back stays.
	View through rear window opening showing bolt through attachment to chassis. Horizontal loop in bottom right is for seat belt attachment.
	Detail of a-pillar tube with door bar and dash tube. Bottom mounts onto built up section of chassis running through the door sills.

Date	21-Mar-2012
Pictures by	Andy & Webmaster