New Tri-Five Pro-G IRS for ’55-’57 Chevys

Wauconda, IL, August 15, 2012 – Heidts Automotive Group used the 43rd Annual NSRA Street Rod Nationals Plus at Louisville, KY to introduce a bolt-in, high-horsepower Independent Rear Suspension System for 1955 through 1957 Chevrolet cars. This bolt-in rear suspension system is based of the proven and award-winning Pro-G IRS design and adds yet another popular vehicle to the ever-growing lineup of fully engineered front and rear suspension systems and components.

The Tri-Five Chevy owners have been asking us to develop a true, bolt-in IRS solution for them to put under their cars,” says Mike Hawley, Heidts Sales Manager. “These cars are hugely popular with both customers and our dealers and are built from mild to wild. This new bolt-in high horsepower Pro-G IRS will allow them to take the ride and handling of these classic builds to a whole new level of performance.”

“When we set out to develop this product, our engineering team had one goal: make the BEST bolt-in IRS solution on the market – period,” says Jim Shaw, one of the Engineering Team members at Heidts that developed  the Tri-Five Pro-G IRS. “The bolt-in feature means this Pro-G IRS can be installed on cars that are already complete or easily added to builds already under way. The ’55 to ’57 Chevy chassis provided some unique challenges, but we addressed them all and even made a few design enhancements to make exhaust routing easier.”

“We know that this application is going to be a big hit with our dealers and will allow them to introduce Heidts’ award-winning design and engineering, along with our best-in-the-industry customer service to a whole new segment of hot rod and street rod customers,” adds Hawley.

New: Tri-Five Pro-G IRS (Independent Rear Suspension)
Responding to the request of our dealers and customers, the Heidts Engineering Team has developed a high-horsepower, ’55-’57 Chevy application of the award-winning Pro-G IRS design and geometry.

The Tri-Five Pro-G IRS features a fully welded and boxed upper cross member, heavy-duty upper and lower control arms, fully welded uprights, heavy-duty constant-velocity joints and axle shafts as well as Heidts’ own cast center section that can be loaded with a ride range of gear ratios and posi-traction differentials.

The Tri-Five Pro-G IRS also makes use of standard 10.5-inch inboard mounted disc brakes with four-piston Wilwood calipers. Based upon the intended vehicle applications, the Heidts Sales Team will help the customer select the proper spring rates for the coil-over shock assemblies. The Tri-Five Pro-G IRS is available in both 56- and 58-inch wheel track versions.

The Heidts Tri-Five Pro-G IRS package includes:

  • 9-inch aluminum housing
  • 3rd member, iron, posi-traction differential
  • HD CV Joint Half-Shafts
  • Tubular Upper and Lower Arms
  • Steel Outer Uprights
  • Fully welded and boxed Top Cross Member
  • Frame Mounting Brackets
  • Front Pinion Support
  • 10.5-inch Wilwood brake rotors
  • Black Wilwood brake calipers
  • Billet, Single Adjustable Coil-overs with Chrome Springs

Heidts Tri-Five Pro-G IRS Options include;

  • 56- or 58-inch Wheel Track Widths
  • Choice of Gear Ratios
  • Choice of Spring Rates
  • Choice of component finish: Raw or “Show Package” of polished and chrome steel components and polished center section
  • Parking Brake Kit and Cable Kit

Manufacturer Suggested Retail Price:
MSRP for the new Tri-Five Pro-G IRS starts at $7,995 (options extra) with units in stock and ready for shipment.

For more information on this or other industry-leading Heidts products, contact your local Heidts dealer, call Heidts directly at 800/841-8188 or visit our website at

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