All You Need To Know About Roll Cage Fabrication & Design
Most car enthusiasts, especially racers never mind spending cash for the extra performance and safety of their cars. One of the crucial upgrades that racers are considering today is a ‘roll cage’. Well, the name suggests a bit of what it does!
A Roll Cage is quite a modern invention in motorsports which is a structured cage made of some random bars of solid material like steel. Roll cages or roll hoops were already prevalent but they were not really the full roll cages that we are talking about, and which appeared lately.
In the early years, cages were only used to strengthen the chassis of cars. Engineers then gradually improvised the structure and made them into full cages to protect the driver in case the car rolls over or faces a collision.
Needless to say, roll cages are a prerequisite for race cars as well as other off-road cars. The key reason is the worst hit or rollover that a car can face at any time while driving at a high speed. Considering that, they are an integral requirement in race cars for safeguarding the life of the driver.
When it comes to installing a roll cage, no way you can take chances but install a cage with the best structural design. Fortunately, there are custom race car manufacturers that will help you with custom roll cage fabrication and installation to ensure the level of safety you need.
As specialized race car builders, we discussed roll cages in detail in this blog. Learn about it and decide why fabricating a roll cage for your car is a much-needed step today.
What is a Roll Cage?
To say it simply, a roll cage is a protective or safety structure designed for sports cars or off-road vehicles to keep the driver safe during any collisions or accidents. It is a specifically engineered frame of strong metal bars built into the passenger cabin of the vehicle. It is needed for protecting the driver or occupants during a crash or rollover.
The roll cage prevents the car cabin from crushing down on itself during collisions or rollover, thanks to its supreme rigidity. The cage gets its rigidity from the welded steel tubing used to build its structure. Also, the geometric shapes that form the structure of the cage give it further rigidity.
While some vehicles construct the cage outside the vehicle’s cabin, some do that inside. In whatever way it is installed, the purpose remains the same.
The type, shape, or size of the roll cage differs for cars. So, to install it, you need to get it manufactured by a custom race car builder. The builder will handmade a roll cage that seamlessly fits into your car with no modifications required anywhere in the car or cage.
What Is Roll Cage Fabrication?
Roll cage fabrication is the process of manufacturing roll cages for motorsports vehicles. It involves the process of cutting, meandering, assembling, structuring, and welding the steel to build a perfect cage modified to the shape and size of the car’s passenger cabin.
The roll cage fabrication process is needed for dictating the configuration and build-up of the cage. If your race car needs it, then there are certain variables to consider apart from the best material to use.
A roll cage is quite different from a roll bar which is also a safety requirement for the driver. While the roll bar is just a single hoop behind that protects the head or shoulder, the cage offers extensive protection to the driver.
That’s why the term fabrication is used! It involves the construction of a cage-like safety structure that involves several metal tubes. When installed in the car, it offers all-around protection to the car’s driver.
To understand well the process of roll cage fabrication, you need to first know about the types of roll cages that we’ll take you through them in the next section.
What Are The Various Types of Roll Cages?
When it comes to installing a roll cage, there’s no one-size-fits-all. Since there are various car models of different cabin sizes, it calls for roll cages with different specifications. Roll cage also differs according to their specific applications and so has many designs.
You need to understand that you cannot just assemble the metal tubes to construct the frame and name it a roll cage. You got to know what it takes to construct a full cage that offers comprehensive protection to the driver. It’s primarily the design. Due to this, different designs of roll cages are found specific to various cars or uses.
Roll cages classification is done based on several factors. But, we thought to outline here the types based on the two most vital factors- installation type and the number of points present in the cage.
Types of Roll Cages Based on the Installation Method
Depending on how the car builders install the roll cage in a car, there are two types of cages.
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Bolt-in roll cage kit
As the name says, bolt-in roll cages are installed in the cars using bolts. These are designed intricately in a way that they can even transform a street car into a drag racing car. It is because the cage perfectly aligns with the car’s interior allowing the driver to enter and leave the cabin easily.
The bolt-in roll cages are made using precision fit, slip tube, and 6-mounting point. The bolt-in design is generally not fit for high-speed racing cars but is useful for non-racing cars, rally cars, or any off-road vehicles that need extra protection for the drivers.
There are certain advantages of bolt-in roll cages too. You can remove the bolts and different structures and reinstall them in another way if you want. Also, you do not need to powder coat them, and hence, there’s no need to paint the structures which saves your costs.
Compared to the welded roll cages, these offer less protection and so you should not consider them for your drag racing cars.
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Welded roll cage
This type of roll cage is welded into the car and professional welders or roll car builders do that! For the method involved, it offers more strength to the roll cage kit that is better at withstanding collisions during accidents or rollovers. Needless to say, if you own a race car and take part in drag races, a welded roll cage is one of the fundamental requirements to consider.
Welded roll cages further comprise two types- U-weld front cage kit and U-weld full cage kit.
In the former type, the cage kit is first welded to a roll bar and then constructed into a 6-mounting point roll cage. The tubing size for the cage depends on the car type and the manufacturer decides that after you place the order for roll cage fabrication. Most of these cages include 2 support brace tubes, 4 door guards, under dash bar, 1 Top windshield cross tube, 4 top corner gussets, and backup plates for necessary mounting and fitting.
The U-weld full cage kit is welded into a 6 mounting point roll cage that closely conforms to the interior structure of the car. It uses a precision fit and is most suitable for cars meant for drag racing, rally racing, and other high-speed performance vehicles. This second type of welded roll cage kit is known for its perfect construction and fit. They are made according to the tube size required for your particular car.
Types of Roll Cage Based on ‘Point’
When you decide to install roll cages, you will hear types such as 4-point roll cages, 5-point roll cages, and so on, from the roll cage builders. The digit determines the number of points where the cage kit is attached to the car’s body.
Understanding the difference between each of the ‘X’ point roll cages is simple! A 4-point roll cage has only 4 points mounted to the body and hence provides limited protection than a 6-point or 8-point roll cage. The latter can protect the driver and the driver’s cabin from all sides.
Typically, there are four types of roll cages depending on the ‘X’ point system – 4-point, 6-point, 8-point, and multi-point system. In the high-end variants, there are diagonal sidebars that are purposely made to help the cage withstand the weight of the car and prevent collisions during rollovers.
If you are planning to get the first roll cage installed, we can guide you here with the prominent types of roll cages known. Since we have spent years manufacturing parts of drag racing cars, we know that these types afford maximum safety, which makes them suitable for your sports car.
How To Identify a Good Roll Cage Fabrication?
Before you search for a car manufacturer that offers roll cage fabrication, get acquainted with the major factors that ensure a roll cage is strongly built and caters to your safety criteria. Here are the major factors we as professional race car builders emphasize:
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Material
Considering the fundamental purpose of the roll cage, structural resilience is the first thing to ensure. The material, its fabrication, and the technique of installation determine whether it’s a good roll cage or not.
For maximum cars, welded steel is the best material type to use as that gives enhanced rigidity and full protection to the occupants.
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Weld quality
Weld quality is vital to ensure that the cage will hold everything together and prevent the collapse of the vehicle during a mishap. Good welding thereby assures to prevent of injuries to the driver. The popular types of welding applied to cars for maximum endurance during accidents are TIG (Tungsten Inert Gas) and MIG (Metal Inert Gas) welding.
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Contact points
Choosing to weld the cage to the car’s floor is an easier thing to do but it’s also riskier. In case the car overturns, the floor can tear away due to the pressure of the roll cage.
For this reason, the best roll cage fabrication technique involves welding it to the box sills of the car.
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Distance from the car body
The lesser the distance between the cage body and the car body, the better it is. When there is greater space between them, it lessens the internal space of the car and reduces the protection level ensured by the roll cage.
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Legality
When installing a roll cage, make sure to check with your race car builder that the cage meets the standard criteria and legal requirements underlined by the USA.
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Eligibility
Also, a prerequisite for a roll cage is that it should be built with the solid cage material that makes it suitable for the purpose i.e., protection from rollovers or accidents. Cage materials vary according to the type of cars or their build. Thus, make sure that the cage material chosen for your car is surely eligible for the purpose!
Roll Cage Design: How It Is Done?
As expert race car manufacturers, we have been fabricating custom roll cages for years. When it comes to forming the design of the cage structure, we just consider the main lines of the car. In other words, we take an artistic approach to design the cage and create it with pen and paper or photoshop.
For instance, if it is a Mustang, we will lay the lines over the top all over the body and observe what fits well and looks good. After we have figured out the structure by laying lines, we decide how much material is required for fabrication.
Considering how the cage is built, there’s also scope for creativity which means you can re-bend some metal bars and reduce the use of material. To put it simply, every angle and inch of the roll cage depends on the car and how you want the structure to operate.
Materials Used For Roll Cage Fabrication
For building the roll cage, mild steel, and chromoly steel are widely used. Both are known for their remarkable strength. While the tubing needs to be thinner for the cage, there’s no question about the strength that it offers. For this reason, roll cages are comparatively lightweight which makes fabrication easier.
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Mild steel:
This has a special place in the field of roll cage construction because it has greater yield strength and offers ease of welding. Mild steel is a low-carbon alloy that has other elements like manganese. It can be bent into any form. This makes the welding of the roll cage fabrication parts smooth and hassle-free.
Mild steel varies according to the composition i.e., the percentage of carbon present. Variations of mild steel that are widely used for their maximum tensile strength are ROPT510 Mild Steel and BS4 T45 to BS5 T100 Steel. These are widely used for roll cages and chassis in drag racing cars for their strength specifications that meet the standards provided by the authorities.
We prefer ROPT510 Mild Steel more because it also has a shock absorption property which helps to prevent high-impact shocks during collisions.
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Chromoloy:
Chromoly or chromoly steel is an alloy of chromium and molybdenum, which offers maximum strength per unit to roll cages. However, there are some challenges in welding and the heat-exposed areas where they are welded tend to become brittle under stress. Thereby, we do heat treating after final welding to minimize the risk. TIG welding is suitable when you use Choromoly for your roll cage to ensure tight fitting at all joints. Owing to this, you need to emphasize the fabrication process while using this steel alloy.
Mild steel is better for use when you emphasize cost or affordability. Also, for chromoly, we need to apply TIG welding which is a bit more challenging to master than MIG welding.
Apart from these two, materials that are commonly used for building roll cages are T45 steel, 15CDV6 steel, and Docol R8 Steel. All these are alloys of steel with other metals like chromium, manganese, carbon, etc. Let’s get through the specific steel alloys in the next section.
Best Materials For Roll Cage
With lots of variations in steel types or alloys that are used for building roll cages, it is interesting to know which ones rank the highest in terms of tensile strength. In the case of roll cages for drag racing cars in which budget is not much of a concern but safety is, these are the top-grade and strongest materials.
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15CDV6 steel:
This is steel made of chromium, vanadium, and molybdenum alloys. Besides being the toughest steel, it is easy to fabricate a roll cage with it for its enhanced bendability and smooth welding characteristic. It’s even stronger than mild steel but is one of the most expensive roll cage materials. If you are wondering what is the best material for the roll cage, this is it!
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Docol R8:
This steel alloy made of molybdenum and chromium is the next sturdiest material you can count on for building the roll cage of your race car. Its higher yield strength along with the easy-to-bend characteristics makes it an appropriate material for cages in motorsports cars.
Worst Materials For Roll Cage
Roll cages are for providing added protection to the driver and car’s interiors. So, why choose a material that is itself not sturdy enough and can break during the collisions causing further tear and wear to the car? While choosing the material for roll cage fabrication, make sure to avoid the following materials.
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Aluminum:
It is the most terrible choice of material for roll cages because of its lower yield strength and brittleness.
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Stainless steel:
Stainless steel is also considered but it is also a worse choice, low yield strength is the prime cause behind it. It is also challenging to weld which needs the TIG method.
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Magnesium:
If there’s any material that is not found in tubing and is tough to weld, then it is magnesium. It is for this reason magnesium or any of its alloys is the absolute worst choice for a roll cage. Also, it’s brittle with very low yield strength.
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Titanium:
It may look strong and appealing for roll cages because of its brilliant yield strength and lightweight feature. But, Titanium is also one of the worst materials to consider because it is exceptionally challenging to weld and is highly brittle. It’s also typically more expensive than other materials.
What’s the Significance of Material Weight in Roll Cage?
Choosing a material with lesser weight for your roll cage construction is a necessary condition. A heavier roll cage will impact the speed of the car and hence, its performance on the track. Race car manufacturers hence determine a minimum diameter and tube thickness for the cage structures.
Since all of the materials used for building cages are steel alloys, they weigh almost the same with densities within a nominal level. As a result, you got to be focusing only on a higher-grade material with considerable yield strength instead of a lightweight material.
What are the Races that Your Car Participates In?
Before you dive into the process of roll cage fabrication, understand in what races your car will compete. Depending on that, the sanctioning body determines the type and material of roll cages required in your roll cage.
Some of the popular races are NHRA, Formula D, and SCCA, each of which has different rules for car fabrication. The authorities specify rules for everything, but especially for the tubing material, size, and bar thickness. Thus, you have to learn about the rules to build your roll cage’s specifications according to them.
Which Is The Ideal Option To Apply for a Roll Cage- Tube Or Pipe?
For a roll cage, it is always the tube. It is because of the thickness you get with Drawn-over-mandrel (DOM) tubing. There’s no specific material required for the DOM tube but mild steel, Chromoly, or any other steel alloy is often used. They offer an added advantage for their extraordinarily strong ID/OD tolerance.
In contrary to this, the pipe is always weaker than the tube made of any material. Pipes are no doubt rigid but they cannot be shaped into a particular structure seamlessly like the tube. Besides, pipes are only useful for applications that need to handle pressure from the gas or liquid flowing through the inside. Tubes being stronger are used in small diameters to build rigid applications to provide strength to a structure.
How much tubing is essential for a roll cage?
The length and diameter of a roll cage depend on the type and design of the cage that you need for your specific car. For instance, a basic 4-point roll cage just needs 4 to 6 tubes and each must be approximately 20 feet long.
Key Roll Cage Fabrication Tools You Should Know About
The roll cages are specifically engineered for race cars to provide unmatched protection to the driver and interior parts of the race car.
Needless to say, some exclusive tools are needed for roll cage fabrication and here we will help you get acquainted with them.
- Tape measure- Used for measuring the dimensions of the car.
- Carpenter angle finder- For taking a precise measurement of the angles.
- Hand grinder- For making fishmouths and finishing the ends.
- Tubing notcher- Useful for cutting round notches at the end of the tube.
- Tubing benders- Needed for bending corner tubes and it is the main tool required for manufacturing a roll cage.
- Metal pipe cutter- For fragmenting the tube into smaller parts.
Apart from these specific fabrication tools, the roll cage builders also need basic tools like Hammer, Permanent Marker, Welder, Hand Grinder, Level, and Carpenter Square.
Tips on Selecting The Right Roll Cage For Your Car
As pioneering race car builders, we have been providing tips frequently such as drag racing tips to outperform on the track. We not just strive to build high-grade car components and safety equipment for race cars but also want you to know how to escalate the performance of your cars.
In this comprehensive guide on roll cage fabrication, we have curated some tips to get the perfect roll cage for your car.
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Pick the material carefully:
A strong roll cage is the one made with the best material like 15CDV6 steel and Docol R8. Apart from that, check whether it has the correct tubing. We consider tubing with 1.75 inches or 4.45 cm diameter ensures the cage structure to be sturdiest ensuring maximum protection to the driver and car.
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Check the weld quality:
Unless the welding is fail-safe, you cannot consider the roll cage to be effective as safety equipment. While both TIG and MIG welding methods are used for fabricating roll cages, we consider those welded with TIG techniques to be one step ahead in terms of durability.
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Keeping the parts tight:
The reason to get a custom roll cage shop and get it fabricated is because the ready-built kits never fit appropriately to the car body. They not just consume a lot of the space in the cabin but also offer less protection. Thus, get a custom roll cage design crafted for your specific race car that fits tightly into its body.
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Use of sills:
Check from your custom roll cage manufacturer whether the cage will be fixed into boxed sills of the car. It ensures more safety because when the cage is attached to the floors, it can easily tear the floor when the car is subjected to collisions.
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Painted cage:
While painting your roll cage might not level up the protection but it will make your car look stylish and professional inside.
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Legality:
Do not just search for roll cage builders on the internet and go for anyone! Make sure to get a builder that knows about the specifications and rules of different racing events. They can help you fit a cage that fits aptly to your car as well as meet all legal compliance needs.
Step-by-Step Guide for Perfect Roll Cage Fabrication
Before you search for a roll cage fabrication shop and get into the process of manufacturing, learn about the rules or formal specifications underlined by the governing bodies of drag races. The rules regarding roll cage fabrication, material, and type vary with the race events. You need to get acquainted with the rules applicable to the races that you are participating in or will participate in future.
Once you have developed an understanding of all the applicable rules, get in touch with a reliable roll cage installation shop and follow these steps.
1. Measure the dimensions of the car
Most times, the roll cage builder will do this easy step but you can just skip this step for them and do it by yourself. To get a roll cage design that fits appropriately into the car without any loose joints, take accurate measurements of your car using tape.
Measure the height of the car, the width of the roof, the width of the car, and the length from roof to side. Other measurements required are door brace, rear brace, seat cross member, and base plates.
2. Design the roll cage
Here comes the main step of the roll cage fabrication process which includes multiple steps. First, determine how to structure the cage so that every frame provides complete protection. Next, use gussets and minimum tube bending to ensure less stress in the corners.
While squares are structurally worn, use diagonal bars in the cage design and spilt them into two triangles that give enough lateral support to the structure. The best part to ensure the strength of the cage is to put every tube as a part of a triangle.
Other aspects that you should be considered in the design are T-junctions, down bars, kicker bars, and padding.
3. Bend the tubes for a perfect roll cage
This step depends on the tube bender and specific dye that the roll cage construction shop use. But, here are some technical guidelines that must be essentially followed during the step. So, make sure to check with your roll cage builder whether they are following these or not.
- Using a lubricant while bending make the bends smooth and clean while minimizing the scrap.
- Ensure the bends are without deformities as the authorities may inspect them and reject the ones that have deformities.
- Check for the guidelines provided by the authority of your particular race event. For instance, the regulations of some races specify that the roll cages must have Mandrel bends.
4. Cutting the Tubes
With the help of the tube notcher, the roll cage builders cut the tubes in a precise manner ensuring that they will fit together well. The authorities even provide rules for the fitment or weld gap.
For instance, the gap must be as much as the diameter of the welding filler rod material in case the roll cage joints are made with the TIG welding method. This particular rule is applied by SFI which sets and administers standard requirements for racing car equipment including safety equipment.
5. Welding
We come to the last step of roll cage fabrication i.e., welding. For ensuring high-quality joints, we recommend you use the TIG welding method. Also, top-level authorities in the racing field like NHRA made it clear that TIG welds are suitable for roll cages.
Before the roll cage builders start welding, it is compulsory to check that all the tubes fit well into each other. We make fishmouths on the end of tubes to make the job of welding and fitting easier.
A pro tip for welding:
Make sure that every weld is fully penetrated and not just over the surface to develop a strong joint. Also, never clean the welded joints mistakenly using a grinder which can instantly weaken the strength and rigidity of the welds.
What is the Cost of Manufacturing a Custom Roll Cage?
Now that you know what are roll cages used for or how they are built, the next crucial question that we thought to answer for you is what is the cost of building a roll cage. Well, there is no precise answer to this.
The cost of a roll cage fabrication depends on the time needed to build the cage, the material, type of the welder used, and so on. In general, the cost of a custom roll cage made using simple tools range between $2,500 and $4,000, if there are no high-end parts involved.
5 Essential Factors to Consider While Building a Roll Cage in a Car
In the last part of this comprehensive guide, we thought to make you aware of a few decisive factors to keep in mind during the roll cage fabrication for your custom race car.
1. Focus safety over good looks
No doubt, your race car needs to look cool and dashing on the race track for creating an impact on the audience. But, that does not necessarily imply that the safety aspect of the car can be sidelined. So, emphasize more on the safety aspect of your cage construction rather than giving importance to the looks.
2. A costlier approach means safer and better
Never hold yourself back from choosing the costlier materials and expensive fabrication tools. It means you are spending on the sturdiest or toughest cage structure that provides added protection.
3. Go for specific roll cage construction
While roll cages are nowadays also a usual safety requirement also used in street cars, they are an inevitable specification for race cars or off-road vehicles that involves aggressive driving. Those cars are prone to risks of accidents, massive rollovers, or collisions.
A roll cage that is built perfectly according to the dimensions of the car and specifically fits into it is required to protect the racer and car.
4. Weld in the right way
Most structural failures of any equipment occur due to poor welding. Welding holds all the parts of your roll cage together to give complete protection. As experts, we recommend you specifically go for a manufacturer of custom roll cages that has professional TIG or MIG welders.
5. No compromises
Remember that a roll cage is life-saving equipment that you need in your high-speed racing car. So, pay for whatever basic and specific roll cage fabrication accessories are needed for your structure. Whether it’s gussets, crossbars, door bars, or windshield brace, just add it!
Best Roll Cage Fabrication for Your Race Car at Redeye Race Cars!
Roll cages, mostly made of welded steel tubing, are mandatory safety equipment for a sports car. Due to their aggressive driving styles involved in drag racing, those cars can collide or rollover during an accident on the track. Roll cage prevents the car from collapsing and injuring the racer or causing any fatality.
However, what causes the superior strength and rigidity of the roll cages? It is the powerful tools, methods, and fabrication parts used in the cage structure. While we hope that this guide on roll cage fabrication will help when you are about to build a cage for your car, you can also lend our expertise in making it.
At Red Eye Racecars, we are specialized custom race car builders offering services for full custom turbo kits, custom carbon fiber interiors, full tube chassis kit, and custom roll cages. Get in touch today for fabricating a roll cage that flawlessly fits into your car and assures maximum safety!
FAQs
Q1. How Should I Design My Roll Cage?
A. To design your roll cage, look for a specialized custom roll cage builder. Find the best manufacturer out of the lot that can offer you a roll cage made with top-grade materials and welding techniques. Remember to choose a race car manufacturer that offers custom structures and not just kits. After evaluating the dimensions of your car, they will design the cage and fit it seamlessly into the car.
Q2. What are ERW, DOM, and Chromoly?
A. All of these are mild steel types, especially alloys used for manufacturing roll cages. ERW (Electric Resistance Welded), DOM (Drawn Over Mandrel, and Chromoly vary in their strength depending on their composition. All of these result in perfect tubing material for building roll cages. However, of all the three, Chromoly is the hardest. DOM comes next and ERW is the weakest of them.
Q3. What kind of tubing is needed in the manufacturing of a roll bar or cage?
A. For a roll cage or a roll bar, welded steel tubing is always used. The dimensions of the tube usually depend on the weight of your race car.
Q4. In what cases DOM tubing is better than ERW?
A. Both are mild steel products but DOM is considered superior to ERW by some of the manufacturers. Technically, there’s no seam line inside the tubing, and fabricators consider it more suitable for use in a roll cage.
Q5. Do half and full-roll cages considered illegal for public roads?
A. It completely depends on the laws or regulations provided by local authorities in the places where you are driving the vehicle. Many cars today have half or full roll cage protection as it is legally permitted in those regions but the same is not allowed elsewhere.
Q6. Which type of weld TIG or MIG is used in roll cages?
A. While both types of welding are used in roll cage fabrication, many manufacturers and even race car authorities consider TIG welding to be appropriate for the roll cages. It’s because TIG welds offer better penetration of the metal which makes it stronger than MIG.
Q7. Is the TIG welding process easier than MIG welding?
A. MIG welding is a lot easier than TIG welding and it is also faster to grasp. But, technically, TIG welds are cleaner, more precise, and stronger than MIG.
Q8. Do I need to install a roll bar?
A. If you are thinking to install a roll bar, we suggest that you shouldn’t do it. Roll bar kits are also safety equipment for cars but they do not provide enough protection to the cars in case of rollovers or accidents. A car just having a roll bar can bend and deform causing serious injuries or fatalities.
On the other hand, a car with a roll cage can withstand the immense shock or collapse from the rollover or accident. The cage structure has enough strength due to the welding and tubing. It flexes before the head or any part of the driver strikes against the hard body of the car. That is why you need to put a roll cage instead of a roll bar in a racing car.
Q9. Do I need a roll cage kit or a custom roll cage?
A. The roll cage kits are cost-effective but they aren’t always the ideal solution for race cars. The tubes in a kit are already cut and notched. However, they may again need some extra cutting and notching to perfectly fit into a car’s design. For this reason, it is recommended to build a custom roll cage fabricated by an expert custom car builder.