Custom-Fit, 4 x 2” Frame Systems

The custom-fit frame design system is an extremely versatile engineering and construction approach, which enables Chassisworks to expertly prepare a sub-assembled kit or complete factory-welded frame, built precisely to your project requirements. Front hub-to-hub width, ground clearance, wheelbase, and rear frame width can each be varied independently to create a correct fitting frame and vehicle stance for projects including g-machine and pro-touring muscle cars, custom street trucks, pro-street classics, and more.

g-Machine front crossmember

The heart of the custom-fit frame system is Chassisworks g-Machine front crossmember, featuring rack and pinion steering, and double A-arm suspension with anti-roll bar.The crossmember and frame rails are made from 4x2x.120”-wall box tube, mandrel-bent on a computer-controlled tube bender for precision fit and wrinkle-free bends. One of four rear suspension configurations can be selected, each with its own list of options. Chassisworks flexible manufacturing approach enables frames to be built for the broadest performance range of any manufacturer.

Front Hub Width

Our exclusive crossmember design is available in fifteen different widths, allowing the front hub-to-hub width to vary between 51” and 65” in one inch increments. The crossmember, rack and pinion, and anti-roll bar are built specific to the each hub width to maintain correct suspension and steering geometry.

Using measurements taken from the vehicle and actual tire and wheel combination, the correct hub-to-hub and crossmember width can be determined. Dimensions are simply filled in on the crossmember worksheet and submitted along with your order. Worksheets available here.

Ground Clearance

Frames are available in two different ground clearance heights of 4-1/2” and 6” measured at the lowest point of the frame rail. This dimension is based on a 25” rolling radius tire. Further adjustments to ride height can be made using different tire and wheel combinations, optional extended-eye shocks, and to a small degree, spring preload.

Wheelbase Length

Factory-welded frame wheelbases are made in one-inch increments and can accommodate nearly any type of vehicle. When shipped as an unassembled kit the front frame rails are left intentionally long and are trimmed to the desired length by the builder.

Rear Frame Width

The rear frame width is based on tire size and clearance between the fender and frame rail. This information also determines the proper width of the rearend housing and placement of the suspension brackets.

Our custom rearend worksheet helps calculate all the dimensions needed to accurately build the rear frame and rearend housing to correctly fit your project. Worksheets available here.