Protech Racing
Well-known member
I had lots of roll cage data gathered over the years concerning cage feet punch through on sedan floor pans. Mostly bolt in cages that had been welded. The " crush box" is the result .
http://www.ogren-engineering.com/patent ... tions.html
Let me say that most of the road race rollovers inpacted inverted off of the pavement. Having more than one contact point will reduce the depth of impact and lateral loading associated with dragging the car down track upside down. Simply , a nice 4 pt cage with keep the driver further from the ground most of the time.
If the driver moves enough to contact the front down tubes ,than maybe you have a driver restraint design issue .
The Pictured cage solo hoop on the above sight will bend the driver side hoop just above the door. The second hoop will fail at or near the shallow bend on the top bar, near car center.
All cages will fail at some point. Most hoop failures will also fail the base joint at the sils or floor or whatever the bottom is joined to. I now run a lower door bar fixxed to the sill and fix the seat to this bar . At the point of punching the cage out of the bottom of the car the driver may go with the cage out the floor of the car.
My involvement with all this started a long time ago.(1982 Spencer speedway) I tried to buy a Dart/Duster 318 to race at the local oval track. I could not find a Dart, so I built a Buick that I found a full sponsor for. (Art Wilberts Buick/GM parts). The pavement and the dirt track(Canandaigua) shared rules so we raced both tracks . The fastest Dart rolled hard at canadaqua and punched the cage out the bottom of the car killing the poor kid.
http://www.ogren-engineering.com/patent ... tions.html
Let me say that most of the road race rollovers inpacted inverted off of the pavement. Having more than one contact point will reduce the depth of impact and lateral loading associated with dragging the car down track upside down. Simply , a nice 4 pt cage with keep the driver further from the ground most of the time.
If the driver moves enough to contact the front down tubes ,than maybe you have a driver restraint design issue .
The Pictured cage solo hoop on the above sight will bend the driver side hoop just above the door. The second hoop will fail at or near the shallow bend on the top bar, near car center.
All cages will fail at some point. Most hoop failures will also fail the base joint at the sils or floor or whatever the bottom is joined to. I now run a lower door bar fixxed to the sill and fix the seat to this bar . At the point of punching the cage out of the bottom of the car the driver may go with the cage out the floor of the car.
My involvement with all this started a long time ago.(1982 Spencer speedway) I tried to buy a Dart/Duster 318 to race at the local oval track. I could not find a Dart, so I built a Buick that I found a full sponsor for. (Art Wilberts Buick/GM parts). The pavement and the dirt track(Canandaigua) shared rules so we raced both tracks . The fastest Dart rolled hard at canadaqua and punched the cage out the bottom of the car killing the poor kid.