Column To Rack: Design And Fabrication Of Your Race Car Steering

When performing any major modifications to your race car’s steering system, one of the most essential projects along the way is completing the linkage between your steering column and the steering box or rack-and-pinion unit. This scenario is precisely where our Project Rover Camaro stands as we are “teaching an old dog new tricks” by finalizing the steering assembly.

We set ourselves a big goal of dropping over 600 pounds on the front end of our Camaro. Replacing the stock front steering assembly not only dropped serious weight, but greatly improved our steering quality.

With Rover, we are not just working towards a much lighter front end, but we are also eliminating 55-year-old hardware that is now a little sloppy, especially for going fast. We previously installed an IDIDIT Steering Columns and Accessories Pro-Lite steering column. This new addition improved upon the old factory column, which was quite loose and just as tired.

We also removed the original, and comparatively, heavy manual steering box along with the iron center link, pitman arms, idler arm, and drag link assembly. These related steering pieces have been directly replaced with an aftermarket Pinto-style rack-and-pinion steering unit and lightweight aluminum billet steering arms.

Just stripping the original iron steering box and related steering gear had us excited about swapping in a new and much lighter Pinto-style rack-and-pinion steering, along with the related steering shafts and joints from IDIDIT.

The final step is the very involved effort of connecting the steering column and rack together with a proper steering linkage. There are typically two variations of steering joints and shafts used in drag racing.With a lightweight tube chassis, most builders use chromoly tubing and related aircraft-style steering joints. With our Camaro still using the factory front subframe, we opted for a heavier-duty steering system using solid double-D shafts and related steering joints designed to fit these shafts and the splined connection at the steering column and rack steering unit.

Eddie Mohr, Sales Manager at IDIDIT, added some of his experience to our steering project. “Remember, you might need to think out of the box when routing your steering around the chassis, suspension, and headers, while also designing a route with the minimum steering joint angles possible.”

We heeded Mohr’s advice when we realized that it would require some extreme fabricating compared to simply routing our steering around the Camaro’s engine mounts and main crossmember. First, the steering rack needed a much lower location to eliminate bump-steer, and the angle of the steering joint would be too extreme and cause binding.

With our IDIDIT lightweight steering column in place, we used one of their related supports to stabilize the assembly. They include a firewall bearing kit with the column, where we aligned the lower splined shaft with the original Camaro steering centerline.

The rack-and-pinion unit was centered and mounted with tubing that replaced the very front of the Camaro’s two crossmembers on the factory subframe. Careful fabrication prioritized the low rack placement to clear not only the engine’s vibration damper, but also to establish the rack’s proper height in relationship with the steering arm height.

This careful rack alignment eliminates bump-steer that can be caused when the centerline of the rack’s left-right motion is out of alignment with the Camaro steering arms.

Ultra-lightweight options for the full tube chassis are these aircraft-style steering joints combined with chromoly tubing and steering support bushings from RJ Race Cars. Even if you are going to retain your stock steering box, IDIDT offers OEM replacement joints that reduce vibration and offer a much more precise steering assembly.

Another benefit over the original steering box is an improved steering ratio. The original Saginaw steering has a slower steering ratio, with five total turns of the steering wheel from stop-to-stop. That action compares to the new and much quicker rack-and-pinion that turns from stop-to-stop at just under four revolutions of the steering wheel — much quicker for racing agility.

This rack-and-pinion location also requires a steering shaft path that carefully travels through the second, and larger, Camaro crossmember. A narrow path clears the factory engine mounts, the headers, and avoids the suspension’s lower support of the A-arm mounts. The path carefully cuts through the crossmember by removing minimal material to maintain the overall subframe’s strength.

Three factors can easily cause binding as you rotate your new assembly: steering path angles, steering joint phasing, and steering shaft support. These are critical for smooth steering function. – Eddie Mohr, IDIDIT

The rule of thumb when selecting your steering linkage hardware is to find the proper steering universal joint combination that will get you from the column to the rack without binding. “If you find yourself routing the steering mechanism around complicated headers and suspension, you might have to think outside the box,” Mohr adds.

Steering Joint Phasing

Phasing or “clocking” your steering joints can also prevent them from binding during rotation. To properly operate in unison, the two connecting joints must be phased at each shaft’s end.

This phasing is similar in theory to what is applied to driveshafts. The steering joint forks are in line with one another at each end of the shaft. If the yokes of the joints closest to each are not in line, binding of the steering will occur when it is rotated.

This phasing is especially critical when fabricating a steering system with round tubing — lightweight tube chassis race cars typically use chromoly tubing and aircraft-style steering joints. This arrangement of joints and tubing can be connected in any clocked combination before bolts or welding takes place.

In the case of our Camaro, we have opted for a heavier-duty combination of solid alloy steel double-D steering shafts, along with related steering knuckles from IDIDIT.

As we cautiously routed our Borgeson steering joint from IDIDIT through the suspension crossmember, we measured our steering joint angle to make sure we did not exceed the 35-degree limit, which will cause binding as you steer.

In the double-D design, all joints automatically connect to the shaft’s shape in the proper phase. This steering shaft design is very popular with street machines and hot rod applications. The advantage of a double-D shaft steering system is its flexibility during assembly and the durability related to the Camaros factory front suspension geometry.

The double-D shaft gets its name from the unique shape of the shaft’s length with rounded ends combined with two flat faces. In our case, we chose a standard 3/4-inch double-D shaft that measures across the rounded cross-section at .750-inch. The flats on this shaft measure across .550-inch.

Steering Joint Angle

“The first design rule is to not expose your steering joints to angles greater than they are designed to handle,” Mohr explains. “Most steering universal joints can typically offset the angle of your steering shafts by 35 degrees. Just make sure to learn the capabilities of your specific joints.”

Our hard steel shaft must be cut to length with an abrasive cutoff saw. One 36-inch piece from IDIDIT made both of our sections. Once fitted, we marked our set screw contact points and created small recesses to better seat the screws.

Mohr adds, “If you require greater angles, double-knuckle-joint designs can redirect your steering shafts through up to a 70-degree peak angle without causing the universal joint to bind.”

Considering these limits, our accumulated angles from the column to the steering rack required three steering joint knuckles. We are using one joint at the end of the steering column, one to redirect the overall steering at the midpoint, and one at the rack’s splined connection. With some heavy straight wire and a protractor, we mocked up the route of our steering so as not to exceed the knuckle’s angle capacity, meanwhile clearing our suspension mounts and other hardware.

The DD-shaft steering joints are manufactured with the shaft's insert slot aligned or "clocked" in relationship to the steering forks. If these forks are out of alignment, they also can cause binding.

Steering Shaft Supports

“Each time you use more than two steering joints in your overall steering assembly, you have to have a support to the shaft,” Mohr explains. “Using a support bushing or a rod-end, you must hold the shaft firmly so as not to deflect and cause binding.”

In all cases of steering assemblies, if your grouping totals more than two joints or uses a double-knuckle joint, you must support one of the shafts near the center joint. This support is accomplished with a bushing that matches the outer diameter of your steering shafts. In our case, we used a 3/4-inch rod end from Aurora Bearing.

Our rod end is mounted along the inner Camaro subframe with a fabricated pad. This rod end supports the steering assembly at a midpoint away from our headers. At this point, a second shaft will route through our crossmember toward our rack & pinion.

We also permanently aligned our steering column with one of IDIDIT’s column-drop supports; the aluminum dash was not supporting our column securely and allowed flex at our steering joint. We also added inner supports combined with the heavy-duty aluminum column drop to stabilize the assembly.

We maintained a direct path from our steering column to clear our headers. We then used a new teflon-lined rod end from Aurora bearing once our fabricating was completed. The DD-shaft is 3/4-inch across on the rounded faces.

Mohr’s final hints include the shafts’ engagement and steering knuckles. “When connecting the assembly, ensure you cut your shafts to precise lengths for proper engagement. You need a full 7/8-inch of shaft inserted into each joint. On the other extreme, make sure the shafts do not extend too far into the joint so as to come in contact with the knuckle mechanism.”

With the use of the rack-and-pinion steering, the IDIDIT lightweight column, and the IDIDIT steering shaft components, we lightened the weight of our front end by almost 180 pounds,

Weight transfer for our Camaro just took a big change for the better, as our long list of lighter front-end components transferred almost 20-percent of the car’s weight towards the rear.

Our overall goal was to knock over 600 pounds from the Camaro the next time we placed it on our scales. In addition to our new steering, we also added or replaced a long list of other items, including aluminum cylinder heads, a sheet-metal intake, lightened front subframe, tubular A-arms, aluminum steering arms, and spindles. With these updates, we were anxious to get Rover back on the scales.

Our finishing touch to the front-end package for the 2023 racing season is lightweight drag racing disc brakes that replaced the old cast-iron assemblies, and lightweight coil-over shocks that replaced the heavier springs and shocks. Our scales rewarded our overall effort by reading 645 pounds lighter than our original weight.

With the control of extreme front suspension motion off the starting line, and improved high-speed steering at the other end of the ‘strip, this accumulation of upgrades has us looking forward to putting Rover back on the track.

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About the author

Todd Silvey

Todd has been a hardcore drag racing journalist since 1987. He is constantly on both sides of the guardwall from racing photography and editorship to drag racing cars of every shape and class.
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