Suspending the Sidewinder

 
     

For ultimate handling and truck performance, the Sidewinder Dakota diesel sport truck was fitted with custom coil-over suspension.

The stock spring and shock vs. the Progress Group coilover shock/spring unit.


Click thumbnails for larger image

 

Modified Stock Car Product spindles attached to the custom A-arms with Chrysler balljoints.

The front suspension uses Chrysler screw-in balljoints, modified Stock Car Products spindles, and Speedway Engineering Grand National front hubs.

 

Custom A-arms were made for the coil-over high-performance suspension on the front of the Project Sidewinder Dakota.

The front suspension lower control arm (top)and the the upper control arm (bottom) were custom fabricated by Sheldon Tackett in the Banks Race Shop.

 

Special racing front spindles were used with the coil-over high-performance suspension on the Sidewinder.

The racing front spindles required extensive machining for use on the Project Sidewinder Dakota.

 

The custom front suspension A-arms are both lighter and stronger than the stamped steel stock pieces for the Sidewinder.

New fabricated A-arms (top) versus stock (bottom).

 

The coil-over springs/shock were built by the Progress Group for Project Sidewinder.

This is a cutaway view of the Progress Group coilover spring/shock unit.

 

The Project Sidewinder diesel sport truck has low-deflection bearings for precise movement.

Banks’ front suspension as seen from above. Low deflection bearing system insures precise wheel movement.

 

New heavy-duty engine mounts were welded to the frame and the steering box was moved forward in the Sidewinder.

This overhead photo shows the relocated stock steering rack with custom tie rods. The rack was moved to eliminate bump steer.

A complete revision of the suspension was required for the multi-purpose Project Sidewinder Dakota sport truck. Unequal length control arm front suspension with coilover springs/shocks replaces the stock control arms, springs and shocks. At the rear, a four-link suspension with Watts linkage and coil-over springs/shocks will be used on both the special 9-inch rear axle assembly for the street, road courses, and drag racing, and on the quick-change assembly for Bonneville.

Front Suspension

A new front suspension system was designed by Don Alexander and Sheldon Tackett to optimize Project Sidewinder performance for its dual roles as a great handling street/road race sport truck and as a Bonneville record setter. The new suspension uses unequal length A-arms and coil-over springs/shocks. By using coil-over springs/shocks with threaded spring collars for ride height adjustment, the Sidewinder can easily be raised or lowered for specific needs at Bonneville, the drag strip or the street. Motorsports suspension experts, the Progress Group®, provided the coil-overs and springs.

During the Bonneville speed runs, it was necessary to get the front of the Sidewinder very low to minimize frontal drag and reduce the amount of air that gets under the front of the truck at speed. Ideally, the chin spoiler on the Sidewinder is “kissing” the salt at full speed. While the threaded coil-over springs/shocks provide several inches of ride height adjustment, dropped front spindles were also required to get the Dakota down to the desired height while keeping acceptable front end suspension geometry. As no acceptable dropped spindles were readily available, Sheldon Tackett machined two blank Stock Car Products® spindles designed for NASCAR Busch Grand National stock car racing applications. Tubular steel upper and lower control arms were fabricated to provide extra strength and to accommodate the dropped spindles. Heavy-duty Chrysler screw-in balljoints are used top and bottom. Oil-impregnated bronze bushings provide deflection-free A-arm movement. The suspension pickup points were also modified to reduce camber gain during suspension movement. Snubbers from a ’02 Chevy Suburban attached to the lower control arms limit upward travel of the front suspension, while frame mounted rubber snubbers limit the downward travel.

Because of the increased frontal weight with the diesel engine, 1200-pound front springs were used at Bonneville, with somewhat softer springs used for all other applications where the ride height is increased. A 1-1/4-inch outer diameter front anti-roll bar from Speedway Engineering® is used to control body sway. This front anti-roll bar has a .250-inch wall thickness, but it can be quickly exchanged for one with a different wall thickness to tune the suspension for optimal handling.

The stock rack-and-pinion steering box is retained, but moved forward, and custom adjustable steering arm ends with spherical bearings were fabricated to eliminate bump steer, which causes drag and can affect top speed. A custom steering shaft with Flaming River® u-joints was fabricated to connect the steering box to the stock steering column.
 
     

 

The rear four-link high-performance suspension on Project Sidewinder uses Progress Group springs/shocks, and an anti-roll bar.

The rear half of the frame is all custom-built, using narrowed, mandrel-bent 2 x 4 frame rails. The quick-change rearend is suspended by adjustable Progress Group coilover springs/shocks.

 

Four-link high-performance suspension allows precise tuning adjustment on this diesel sport truck.

The four-bar rear suspension (two bars per side) is adjustable. Lowering the upper bar at the front pivot point increases anti-squat, which increases rear wheel traction. Wilwood disc brakes are used at the back as well as the front.

 

A rear anti-roll bar and Watts linkage help control the quick-change rearend for Bonneville.

The rear anti-roll bar, which is also adjustable, lends stability at Bonneville, and is very helpful in any competition involving left or right turns. The Watts link is visible below it.

Rear Suspension

Just as with the front suspension, the rear suspension has been redesigned to use coil-over springs/shocks from the Progress Group. The rear spring rate for Bonneville was 450 pounds, with the street rate somewhat softer. And like the front, the rear coil-over shocks feature threaded collars for ride height adjustment.

While a Quality Machine® quick-change rearend assembly will be used for Bonneville and a Speedway Engineering® Track 9™ Grand National rearend used for all other applications, both assemblies are located by the same four-link suspension with Watts linkage to provide lateral control. All links use Delrin™ bushings for precise, low friction control. A Speedway Engineering 1-_-inch outer diameter rear anti-roll bar, with .090-inch wall thickness, controls rear body roll. This rear anti-roll bar, like the front anti-roll bar, can be quickly exchanged for one of a different wall thickness to tune the suspension. The anti-roll bar can also be preloaded using adjustable links to the rearend assembly. Deist® retainer straps are used to limit downward axle movement without bottoming the coil-over shocks. Rubber snubbers limit upward movement.

About the Shock Absorbers

The Progress Group coil-over shock absorbers are rebuildable to any desired valving, but they are not adjustable while on the vehicle. Since optimum shock valving varies substantially from Bonneville, to the street, to the drag strip, and for road course racing, the Progress Group has valved shocks accordingly for each application. The street valving, however, like the street spring rates, represents a good all-around compromise setup for this sport truck. After all, visits to Bonneville, the drag strip, and a road race course are only one-time things to demonstrate the Sidewinder’s capability with its Cummins diesel power. The rest of the time, this truck is meant for the street.