Steering Geometry

There is a resto-mod trend to change out worn Studebaker stock steering gear boxes with modern rack and pinion set-ups. There are design challenges in doing this correctly.

The new rack has to be mounted safely and solidly to the car frame. The steering column shaft has to clear the engine, exhaust, etc…during engine operation. Even the smallest amount of rub or bind will compromise your steering control and safety. Well engineered, sturdy parts are important. Its not a good idea to go cheap with your replacement parts in this area. Safety is paramount.

Studebakers have a rear steer system. The majority of new cars have front steer. The new steering set-up you install also has to be a rear steer so when you turn the car steering wheel left, your car won’t go right.

Case in point: A person who didn’t understand steering geometrics, installed the wrong set-up in a custom ’58 El Camino. He backed the freshly finished car out of the garage, turned the steering wheel right…the car turned left. He hit a power pole. It took me a day and half to repair his damage and a week to stop shaking my head in disbelief.

This Studebaker steering assembly diagram, from the perspective of the driver’s side front of car shows a stock set-up. Ideally you want the pivot of the tie-rod (which attaches to the end of part #1202-34) to be in the same plane (height and width) as the control arm inner pivots (which bolts to assembly parts #1204-85, #1024-86, #1204-91, #1204-93). By keeping the pivots in the same plane and in close proximity to each other, their working radias of arcs are more closely matched.

When these fulcrum points are not closely matched and the vehicle tires hit a road bump, you will experience bump steer. This is when the car motion suddenly grabs and darts without any steering wheel input from the driver. This bump steer phenomenon will be mild to extreme depending on the placement of the steering pivot (fulcrum) points and can be very dangerous.

It’s advisable to have a custom steering rack made that has both pivot points placed in the same plane as the lower control arm inner pivot points (rubber bushings).

There’s presently a company producing custom width Dodge Omni steering racks that can be modified further to fit the Stude. Another option is to modify Chevy Corsica or Pontiac Grand Am firewall mounted center steering racks. To modify these racks, mount them on the stock cross member at the same plane, using stock Studebaker tie-rods. These type of mods will give you a more precise road feel, however you won’t gain any geometry advantages over the original stock Studie design.

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