Spider rollbar application

Although the Spider is a street car, organizers are becoming increasingly rigid in adhering to helmet clearance rules, i.e. the top of the main hoop of the rollbar must exceed the top of the helmet by at least 2”.

Paul Glynn recommended an elegant solution.

We started with an Autopower race height bar. Paul made two modifications – first, he added some cross bracing behind the drivers seat, next, he added a bracket for a for/aft bar. Paul then fabricated four pads for the base mounting points of the bar, and drilled and tapped them. The pads were welded to the chassis, special care being taken for the two pads at the base of the main hoop to weld them not just to the parcel shelf but also to the vertical metal at the leading edge of the parcel shelf and the vertical metal of the chassis (at either side of the parcel shelf).

This allows the bar to be installed/removed by one person without going under the car.

Finally, a fore/aft brace was added, this is also removable. A passenger can fit in the passenger seat with the for/aft brace in place.

The car can be run in three configurations:

• Track – everything installed
• Street – Autopower bar installed, for/aft brace removed
• It’s raining and I want to stay dry – everything removed

Following are some pictures.

Here’s the basic installation:

This shows the positioning of the for/aft bar, and the mounting point:

Here is one of the main hoop mounting pads:

And the other one:

Rear support mounting pad:

This shows the additional cross brace behind the drivers seat:

Rear view:

Details of the mounting of the for/aft brace to the main hoop: