Alfa Spider Rollbars
By Russ Neely, 05-31-98

This article is about roll bars, specifically 105/115 Alfa Romeo Spider roll bars.

Imagine (if you can stand to) sliding down the main straight upside down in your spider. As if that is not bad enough, imagine sliding upside down through grass strewn with rocks. What is keeping your head off the ground and preventing it grinding away your helmet to expose your scalp?

The front fenders will quickly crush or grind away to a point where the front of the Alfa will be supported by the radiator support and inner fenders. The back will be supported by the roll bar. Now lay a board or long straight edge between those two points. If your helmet is below the straight edge and your belts are tight enough, your helmet will not strike the ground. That is one of the SCCA's requirements for wheel to wheel competition. Another SCCA requirement is that the top of the helmet be at least 2 inches below the top of the roll bar and that the main hoop be no more than 6 inches behind the driver.

If you anticipate running SCCA Solo I events, the above is required. Roll bars are no longer legal for road racing, which is why the 1998 SCCA Solo Events rule book, Solo I Section Q, page 46 references the 1995 GCR or General Competition Rules. I summarized the above requirements from the 1995 GRC.

We will not be running wheel to wheel nor will we be timing any cars. Our event is not a competition of any sort. Therefore, we are technically not running under the AROC Competition Code, which does say in Appendix III -Roll Bars---A.2. "The top of the roll bar shall not be below the top of the driver's helmet when the driver is in the normal seating position.".

The AutoPower race model roll bar installed in my 1982 Alfa Romeo Spider Veloce just meets the minimum I will accept. It is not above my helmet, until I remove the lower seat cushion. I pad the bare metal of the stock seat frame with styrofoam around the edges and fold a bath mat under me.

The bar is 1.75 inch diameter with 0.120 wall thickness. This is the minimum for a spider up to 2500 pounds. It has a diagonal brace to prevent collapse and I welded in a cross brace just below the top of the seat back. The cross brace is of the same material as the bar and primarily serves as a mount for the shoulder harness. The two rear braces came welded to the main hoop slightly less than the minimum 6 inches below the top of the hoop. The angle between the braces and the main hoop is just over the minimum 30 degrees. I measured all this when I first received the bar as I wanted it to be safe. As it came from AutoPower, it just meets what I consider minimums.

The main hoop sits on top of the rear package shelf. Three 3/8 grade 5 bolts per mounting plate go through thin air before going through the backup plate under the floor. It is probably not feasible to mount the roll bar to the floor behind the seat, and still have room to sit. When building a couple of roll bars for the 1988 Alfa Convention, Bill Heller went to great lengths to design mounts that clamped together to avoid crushing the upper and lower sheet metal together. As AutoPower suggested mounting my bar, it is lacking in this area. I plan to weld reinforcement plates of 0.080 or thicker to the floor under the mounting pads on the roll bar. I will put another plate under the lower floor to spread the load from the backup plate. I may also cut black iron pipe to slip over the bolts and keep the upper and lower sheet metal floorboards from crushing together.

The rear braces bolt to the rear pan, just above the driveshaft tunnel. The backup plates are underneath and somewhat hard to get to because of the big T that locates the rear axle. This just barely gives the 30 degree angle I consider minimum. Imagine if you will a bar with no supporting diagonals or 0 degree ones. There would be nothing to prevent the bar from folding over when skidding along the road. It might be advisable to run the rear diagonals through the rear firewall and mount them next to the shock absorbers in the trunk. On the full cage I am designing for a road race Alfa, the diagonals will go to the top of the wheel wells where they meet the inner fender liner and the rear fire wall. This will be almost as high as all the little bolts that hold on the convertible top. On a street Alfa, this would be too high as the top would have no where to fold.

My roll bar fits under the top, there are two small bumps in the material just above the rear window. As the rollbar touches the top, I had to drill out the rivets on two of the bows where they attach by your shoulder. The rivets were replaced with 10 mm bolts drilled for hairpin clips to retain them. I can now remove the clips and four bolts, stretch and wiggle the top bows past the roll bar and reassemble. I try to put the top up in the fall and down any day now, I hope.

The seat will not go back its full range of travel, which can become uncomfortable on long trips. I also discovered in the process of installing my roll bar that at 5'9" I am a tall person with short legs. If you are 6'2", you may sit taller than I do and the AutoPower bar might not be tall enough. My head hits the main top bow during normal daily driving without a helmet and with the seat cushion in place. To gain height, I run with the lower seat cushion removed.