A roll cage is a metal framework built into the driver cockpit in a vehicle. It is constructed to reinforce the vehicle and protect the passengers from serious injury in the event of an accident. Although roll cages are mainly used in stunt and race cars, due to their more vigorous driving style, they are also often found in off-road trucks. Roll cages are not essential for every-day vehicles, although some may be fitted with a simple ‘roll bar’, which is a steel bar that runs up the sides and across the top of the vehicle to provide a degree of rollover protection.
The steel bars in a good roll cage should be braced and welded together, ensuring the passenger section remains intact and stopping the driver from getting crushed in the event of the car overturning.
There are tonnes of different roll cage designs, depending on its intended purpose. Each organisation will have its own design specifications and vehicle regulations, however, 8 and 10 point roll cages are the most basic designs. Some organisations may recommend more intricate 12, or 14 point designs, for a little-added security.
When you are building your own roll cage, the first step is to decide what material to use. Mild steel and chromoly are common choices, these materials are equal in strength, the main difference is their weight. Mild steel is heavy, but won’t burn a big hole in your pocket, whereas chromoly is a more expensive option. The light weight of chromoly will not hinder the speed of the vehicle as much as steel. It simply comes down to whether you are willing to sacrifice performance over cost.
Once you have settled on the material of your roll cage, it’s time to start building, you will need:
• 1 3/4-inch DOM mild steel tubing
• Tube Notcher
• Tape measure
• Metal pipe cutter
• Hand grinder
• Protractor or carpenter’s angle finder
• MIG or TIG welder
Before you start building, you need to make sure you have enough room to install the roll cage. You may need to remove the car seats and carpet.
Take your time to ensure that your measurements are accurate as this will tell you how much length of tube you need. Incorrect measurements could lead you to spend a lot more than necessary! Before ordering your tubing, you should accurately record the following measurements:
• Height of floor to the ceiling.
• Length from the rear of the seats to the front firewall
• Width of the interior.
2. The base plates
The larger the base plates the better! A thick base plate will ensure that the legs are stable once attached. When positioning the plates, the rear plates should sit behind the front seats and the head ones should be fixed at the front of the firewall. You may need to bend the base plates to fit with the ribs in your vehicle floor to ensure they line up and are secure.
3. The main hoop
The main hoop is a continuous piece of tube that’s bent into a U shape which is then welded to the rear base plates with two 90-degree bends at the car’s ceiling.
4. Supporting bar
You will need to use a tubing notcher to make the end of the supporting bar fit into place. One end of the supporting bar should be welded at the front base plates and the other should be welded into the main hoop.
When building your own roll cage, you will need confident welding skills. Ensure that all bars are in the right position and only weld around the joints when you are 100% confident with their placement. If you are competing, your welding will be thoroughly inspected, for your safety, to ensure that the roll cage is secure.
A straight piece of tube should be fitted above the driver’s shoulders, across the inside of the main hoop. The bracing will act as an anchor point for shoulder belts. You may also want to add tubing on the doors for extra protection for both driver and vehicle.
Do not paint your roll cage. After each race/ crash, the welding will need to be inspected and coloured paint can hinder this process. You can varnish the roll cage with a clear coat to prevent rust, so long as the welding inspection can still be completed.
Making and fitting a roll cage should not be taken lightly. If your roll cage is not installed correctly you run the risk of seriously damaging your car and more importantly, yourself!
Here’s to safe racing!