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Check Out The Frame On That One!

A Look At Roadster Shop's Fully Bagged And Independent Tri-Five Chassis

Ryan Manson Jan 10, 2006

Whether it's a house, building, human body, or picture frame, everyone wants a secure, solid substructure. For those of us who pick up this magazine, we want the kind of chassis that to the commoners goes unnoticed--a solid foundation under our ride. Most of us want underpinnings that will handle, ride, have killer stance, and an all-around wicked look. Of course, there are a few different roads one can travel to get the perfect chassis. For instance, grafting IFS or IRS is one way. But the problem with that is it requires precise cutting, welding, detailing, and skills, which not everyone has. On the flip side, there are those individuals who want an easier alternative that will make people stop, stare, and say, "Would you look at the frame on that one!" The Roadster Shop in Elgin, Illinois, is in business for that exact reason.Roadster Shop has been building quality chassis for over 20 years, and in recent years has dived into the realm of the Tri-Five chassis. With the ever-growing demand for a cool Tri-Five chassis, and Roadster Shop's years of experience, they knew they could concoct some kind of replacement chassis that would benefit Tri-Five owners in areas of handling, ride, ease of installation, and the overall "cool" factor. What they came up with is a complete hand-fabbed (to the day every frame is handbuilt; no CNC'ing in this process) full replacement chassis that is built around handsculpted framerails, which are precisely formed, meaning no sharp edges.

The Roadster Shop chassis are constructed to physically resemble a GM Tri-Five foundation, but with a slight twist. The two main turning points of the RS chassis is that it lowers the car by 4 inches (without affecting suspension travel) and allows the use of larger/wider wheels while maintaining a proper turning radius. Roadster Shop also offers lower ride heights with their Pro Touring stance, which puts the rocker panels approximately 6 inches off the ground, or Roadster Shop can raise the ride height closer to stock, if desired. In order to accomplish these goals, Roadster Shop made a few changes to the OE design. The drop in ride height (actually car height--like channeling without the channeling) is achieved by lowering the chassis center main rails, which are constructed out of 4x4 quarter-wall tubing, while narrowing the front frame horns, which are constructed out of 1/8-inch mild steel but still retain the factory appearance and mounting tabs (bumpers, core support, etc.). From there, crossmembers are TIG-welded to the rails on jigs to assure accurate placement. Roadster Shop equips the chassis with 1 1/2 x 0.120-wall tubular center crossmembers, complete with drop-out trans mounts, and in the rear is 1 1/2x2 1/2 square tubing. Each chassis comes complete with body mounting tabs that require no modifications for remounting your sedan, convertible, or wagon--which calculates to a true bolt-on application. Starting with the front, the basic package includes a Heidt's Superide II IFS complete with 11-inch disc brakes, a rack-and-pinion, a sway bar option, and Aldan coilovers. Upgrades to chrome-plated and stainless components are also available. The rear suspension consists of a standard 9-inch Ford housing, 10-inch drums, triangulated four-bar, Heidt's coilovers, with optional sway bars. Third member options range from standard-type to Posi, in a wide variety of gear ratios. Roadster Shop can equip the chassis with any engine/trans mount combo, and set them up so no firewall modifications will be required. Other options include rack location that allows the use of stock steering column (or aftermarket), and Wilwood disc brake upgrade. Roadster Shop also offers custom 2- to 3-inch stainless steel exhaust systems and custom stainless steel fuel tanks with stock or 24-gallon capacity, which come mounted on the chassis.

Although an airbag option for all four corners has been around since the frame's arrival, the latest advent to the Tri-Five chassis takes things to a new level. Roadster Shop worked with Heidts and Air Ride Technologies to develop an IRS suspension system that utilizes airbags. The new Heidts IRS is fully independent and the geometry of the IRS is designed to be compatible with the front Superride IFS (which comes standard on the RS chassis). The rearend is based around a cast-aluminum alloy center housing, which is available fully polished, and includes a Ford 9-inch Third member. The IRS also features inboard disc brakes, and polished Wilwood calipers are standard. Halfshafts include heavy-duty 1350 U-joints and lower control arms are available standard in plain steel, polished stainless steel or billet aluminum. The outer uprights are heat-treated aluminum alloy and use Corvette bearing assemblies. Although coilovers or dual coilovers can be used with the IRS, Roadster Shop worked with Heidts to develop a complete airbag system for the IRS. The system uses four Air Ride Technologies ShockWave 7000 airbags in the rear and a pair of ShockWave 3.0 airbags in the front. The Air Ride doesn't affect the rearends geometry, handling, ride; nor does it affect the suspension travel. Basically, whether you're driving down the highway with the added comfort of Air Ride, or slammed on the ground in the parking lot, the system is more than accommodating. If you're looking to step up your chassis to a fully bagged independent chassis, the matching IFS and IRS with Roadster Shop ingenuity behind it is the way to go.


When Keith Curry shopped for a solid foundation for his '55 wagon, he settled on the Roadster Shop's full, independent-bagged Tri-Five chassis. Keith figured you can't go wrong on a frame that comes standard with a Heidt's Superide II IFS complete with 11-inch disc brakes, rack-and-pinion, sway bar option, and Aldan coilovers. However, considering Curry went with a full Air Ride chassis, the coilover was swapped for a ShockWave 3.0 airbag.

Check out this close-up shot of the Heidt's IRS based around the cast-aluminum alloy center housing, which is available polished.

Every framerail is handformed by a Roadster Shop technician. Each framerail is welded both inside and out for superior strength, completely boxed, and ground smooth for the cleanest look possible.

With over 20 years of experience, Roadster Shop has made chassis building an art. That's why each chassis is hand-fabbed with handformed framerails, precise accuracy, ingenuity, and style. Each aspect is represented in their full independent Air Ride chassis.

Along with a polished center housing the new Heidt's IRS features disc brakes, polished, chromed, or billet aluminum lower control arms, heat-treated aluminum uprights with Corvette bearing assemblies, four ShockWave 7000 airbags, and more.


Roadster Shop
Mundelein, IL

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