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MM Mustang Roll Bar Tech

Maximum Motorsports Roll bar installation photos for each Mustang chassis can be found here.

Increase both safety and the rigidity of your Mustang's chassis with a Maximum Motorsports Roll Bar. Originally designed for the rigors of drag racing, we have expanded our offerings to include roll bars suitable for road course and street driving. Some of the 6-point MM roll bars conform to NMRA and NHRA rules. Designed to fit with the stock Mustang interior, MM 6-point roll bars are more suitable for street-driven cars if swing-out door bars are selected.

Unique Features of MM Roll Bars

Maximum Motorsports manufactures our Roll Bars from the highest quality materials and hardware.

  • All roll bar tubes except the harness mounting tube are 1.75" diameter by 0.134" wall DOM tube (much stronger than the more commonly used 0.120" wall ERW seamed tubing).
  • All MM rollbars are constructed from 1020 mild steel for ease of welding.
  • Harness mounting tube is 1.5" by 0.134" wall DOM tube (this size exceeds the NHRA/NMRA minimum size requirement).
  • Contour-hugging 6" x 6" mounting pads with backup plates sandwich the unibody for safe and strong mounting.
  • All hardware is Grade 5 or higher.
  • Designed to fit with stock Mustang interior.
  • NO WELDING required inside a hardtop Mustang! (Some welding required for convertible models)

Installation

To keep delivery costs to a minimum, we designed these roll bars to ship without the rear braces attached. This requires a minimal amount of welding during installation to secure the rear braces to the main hoop. To conform to the NHRA and NMRA rules, a qualified welder must MIG or TIG weld the rear braces to the main hoop. Once the rear braces are welded to the main hoop, the MM roll bar bolts into the final position in the vehicle, and can be removed from the car as a complete unit. MM roll bars are uncoated, bare steel. For a high quality finish, the installer should paint or powder coat the roll bar as part of the installation.

   Coupes & Hatchbacks

  • During installation, the rear braces are temporarily bolted to the main hoop. This keeps the rear braces precisely aligned to the main hoop, allowing all welding to be done outside of the car. This means you do not need to remove your car's entire interior to avoid damaging it while welding.

   Convertibles

  • We include reinforcement plates for the convertible chassis. These reinforcements are welded into place behind the rear seat to provide a good structural attachment point for the rear braces.
  • During installation the convertible top can be lowered and stowed, which provides very easy access to protect the interior and complete the required welding.
  • The roll bar bolts into its final position, and can be removed from the car as a complete unit.
  • Convertible tonneau covers will not fit after a roll bar installation.
  • Roll bars in convertibles will not accommodate a light bar.

Rear Braces

Rear braces connect the top of the main hoop to the back section of the car. They keep the roll bar upright in the event of an accident, and greatly contribute to chassis rigidity.

  • The rear braces of hardtop roll bars mount to the strong compound curve of the rear inner wheel well, leaving space for the back seat.
  • Unlike some roll bar designs, the rear braces do not extend rearward of the centerline of the rear axle. The MM design maintains a crush zone at the rear of the car for optimum safety.
  • The rear braces are straight, with no bends. This is much stronger and safer than roll bars with bends in the rear braces. NHRA rules prohibit any bends in the tubing of the rear braces.

Door Bars

Door bars increase side impact safety. All 6-point Drag Race roll bars include door bars. Maximum Motorsports makes three different styles of door bars, two of which conform to NHRA and NMRA rules. We build several different 4-point roll bars that do not include door bars, but do have an option for low-slung door bars. The 4-point roll bars, even with the low-slung door bar option, do not meet the NHRA or NMRA rules.

    Standard Door Bars

  • Designed for easy initial installation (no welding), but are not intended to be removed. Conform to NHRA and NMRA rules.

    Removable Swing-Out Door Bars

  • The swing-out door bars pivot outward, parallel with the doors, for easy entry. They can also be completely removed from the car in a matter of seconds! Conform to NHRA and NMRA rules.

    Low-slung Door Bars

  • Designed to stiffen the chassis while also allowing easy access into the vehicle.
  • Made of 1.5" by 0.134" wall DOM tube.
  • Easy installation (no welding) as part of initial roll bar installation, but are not intended to be removed.
  • Does not meet NHRA or NMRA rules.
  • Currently available for the 4-point roll bars for 1979-93 hardtop Mustangs and 1994-2004 convertibles.
  • Available only as an option when ordering a new roll bar. Not available separately.

Diagonal Brace

A diagonal brace significantly increases chassis rigidity and provides additional roll over protection. A diagonal brace may be added to anyMM roll bar. The diagonal brace is made from 1-3/4" diameter by 0.134" wall DOM tube. For the best protection and most chassis stiffening, order the optional diagonal brace (MMRBO-1).

Padding: Roll bars should have padding wherever any part of an occupant's body may come into contact with the steel tubing. This includes hands, feet, arms, and legs, not just the occupant's heads. If you purchase a roll bar, you should also order roll bar padding.

To check the rules for your racing class, we recommend that you get your own copy of the latest NHRA rules by calling them at (626) 914-4761.

Tech: Fox Chassis Convertible Roll Bars

The early 1983-93 convertibles started life as hardtops, and were then shipped by Ford to an outside vendor for conversion into convertibles. This construction method resulted in large production tolerances. The MM roll bar for the Fox convertibles accommodates the large variances in the location of the convertible top components by allowing the installer to easily tailor the rear brace fitment to match the vehicle.

Chro-Moly Steel

MM does not use Chro-Moly steel tube. Because of the metallurgical properties of Chro-Moly, any welded area will have a higher concentration of stress than the surrounding, non-welded area. This concentration of stress can lead to failure of the tube at the welded joint unless a proper post-weld stress relieving treatment is done. Because the MM roll bar design requires that the two rear braces for the main hoop be welded during installation, if we used Chro-Moly tubing those welded joints would not be properly stress relieved before final installation of the roll bar.

Bolt-in vs. Weld-in Installation

The MM Roll Bars for hardtop Mustangs are designed to bolt to the chassis, without welding. The floorpan is sandwiched between the roll bar mounting pads and the back-up plates underneath the floorpan. There is a significant clamping force between the two pads, providing a very secure method of attachment.

While any MM roll bar may be welded into the car, there are serious issues to consider. If the installer is not a qualified "expert welder", the installation may be much less safe than a bolt-in installation. Welding anything to the thin sheet metal Mustang floorpan will create a heat-affected zone around the weld. If the welding is not done by an expert, that heat-affected zone may fail and cause the roll bar to poke through the floor in a rollover accident.

The MM Roll Bars for convertible Mustangs do require some welding to the floorpan. Someone who is a qualified "expert welder" is required for installation of a convertible roll bar.

Roll Bar vs. Roll Cage

A Roll "Bar" is different from a Roll "Cage". A Roll Cage has tubes that extend forward from the main hoop, up near the roof, to the A-pillar, and then extend down to mount to the floor, near the firewall. This puts a lot of structure above and around the driver, as well as providing substantial support for the main hoop. The primary component of a Roll Bar is the single main hoop. The main hoop is supported primarily by the rear braces, and secondarily by door bars, if so equipped. A Roll Cage is difficult to live with in a street-driven car. It reduces headroom and foot room, restricts access, and often requires extensive modifications to the dashboard.