Speedtech Performance ExtReme Chassis and Sub Frames

All Speedtech Performance products are designed and manufactured in our factory in the USA.


Everything else is out, Speedtech Performance ExtReme is in.  The days of clipping cars with Mustang and Crown Vic front ends are over.  Speedtech Performance has revolutionized how custom car builders modify classic muscle cars.

Part of our “DNA” includes maximizing wheel and tire width without the need to change the styling of the car.  With stock fenders and original body panels you will be able to fit exceptionally wide wheels and tires with full steering equal to if not greater than the car’s original turning radius.  10.5” wide front wheel with 315/30/18 is common and, in many situations, wider is possible with no body styling modifications.


Our ExtReme product line is easy to install into the original body mount locations and provides an extraordinary driving experience.  If your dream car is being built to drive across country, across town or around the greatest road racing tracks in the world your search for the right suspension is over.  Our approach to designing award-winning suspension is ExtReme, the results are also ExtReme.

All our Sub Frames and Chassis are extremely ridged due to being fully boxed with internal gussets to maximize strength and torsional rigidity.  Our engine stands can accommodate all Chevy LS, LT, SCB and BBC as well as Ford Coyote and Mopar 3rd Gen Hemi & V10 power plants.  The transmission cross member will accept all engine and transmission combinations.  Along with making our chassis and sub frames very ridged we also have engineered the related components to be durable and provide a great driving experience.

Our optimized dynamic geometry is unlike anything else in the market.  Caster and Camber gain instills driver confidence and provide a direct connection to the road from the driver seat.  With virtually zero bump steer the driver retains a complete sense of control.  We have eliminated the sensation of the car changing direction during undulations even while cornering.  Cars equipped with Speedtech Performance ExtReme suspension are consistent and predictable on the road as well as at the limit on an autocross or road course.  Ride height is fully adjustable to meet your vision of the cars styling and stance.

The ExtReme Spindle is standard and inclusive on all ExtReme front Sub Frames and Chassis.  Our ExtReme spindle is forged from high quality 7075 (T73) aircraft aluminum, it is tough, light and thoughtfully designed to take caliper bolt pattern of a C5/C6 corvette.  Our spindle uses a large, robust sealed double bearing from a C7.  When possible, we look for an existing solution such as the C7 bearing so if you ever need to service it you can get going again quickly with a locally found part.

The steering rack is sweet and also ExtReme.  We have gone to extremes searching for a heavy-duty rack and pinion steering unit that will stand up to the higher loads generated by larger tires and brakes.  The steering racks are race proven dual power steering racks that can also be found in Sprint Car and Stock Car racing.


We offer primarily two ExtReme rear suspensions systems, Torque Arm Rear Suspension (TARS) and Independent Rear Suspension (IRS).

A Torque Arm Rear Suspension holds the rear axle longitudinally while allowing the body to roll horizontally during driving maneuvers.  The result is that no appreciable pinion angle change is possible, this minimizes driveline vibrations.  Rear roll center is adjustable via the pan hard bar and ride height is full adjustable.  One fantastic attribute of this design is all the rear axle loads are transferred to the center of the car minimizing pitch of the body during acceleration and braking.  Body roll is consistent and smooth over the rear axle because of our proprietary Articulink trailing arms. This system is easy to install and can be done in your garage in a weekend.

ExtReme IRS is the ultimate expression of Pro Touring rear suspension.  Game changing ExtReme IRS for your classic muscle car is fully realized in our award-winning rear suspension system.  We offer three different configurations of IRS including High Mount Shock (cantilevered/rocker arm), traditional mount shock and low mount (under car) rocker arm system.  The traditional mount shock IRS is fantastic for maximizing comfort and performance while maintaining maximum trunk area for luggage.  The cantilevered systems boast a greater motion ratio meaning a lighter spring rate can be used while improving ride quality and tire-to-surface compliance.  Our IRS control arms are the longest in the business providing smoother ride with improved durability.  All 3 versions offer fully adjustable rear alignment (camber, toe and bump steer) with some adjustment for roll center.  The half shafts and CV joints as standard are rated to 1200 HP and can be upgraded to handle 1800 HP.

We like cars that are enjoyable to drive, we do what we do for the joy of the drive.  You don’t need to be an extreme driver to appreciate the ExtReme products from Speedtech Performance.  Weather your goals are traveling in your classic muscle car or setting a new blistering fast lap at your favorite timed driving event we will help you reach your goals.  We are extremely passionate about delivering our customers the best driving experience possible.

Camaro front sub frame


4160 S. River Road,
St. George, Utah 84790

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