Speedtech Performance USA llc

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Mustang II Suspension and Corvette Spindle Geometry are Things of the Past!

Extreme suspension

Many aftermarket chassis' suspensions are based on the Pinto/ Mustang II, a suspension that was developed using early 1970's technology; intended for an econobox car that was produced at a time when real performance handling wasn't much a part of American cars’ vocabulary. As an effort to handle better, some aftermarket suspension systems have adapted in the Corvette (or Corvette Copy) spindle and geometry. While that 1990's technology has proven to work better than the older Mustang II, it’s still outdated by today’s standards.

Serious Hot Rods, Pro Touring cars and YOU deserve a more modern ride and handling capability. While others continue to play with the outdated and overrated, we’ve added to our already fantastic line up of performance suspensions an entirely new ExtReme suspension that really is the best system available, period.

The ExtRreme Difference


Through years of development and testing our current Pro Touring line of suspension systems has met the needs of customers world wide, from daily cruisers to weekend track warriors. As track day events are increasing and the competition heating up Speedtech has once again stepped up to lead the industry into the next level of street car cornering performance. Together with veteran road race and Nascar chassis builder Ron Sutton, we've produced a totally new, optimized, push-the-envelope type of suspension that outperforms anything else in the Pro Touring market.

Said Ron, "...we needed to achieve the optimum front dynamic roll center for any suspension strategy the customer wants to run, and we did it, it turned out perfect. This is combined with the best Ackerman of any available front end, optimum camber gain and minimal jacking effect." 

What does this mean to you? Ron continues, "... This makes these the Best handling, steering & driving frames available. They are an upgrade from frankly any full chassis or front subframe in the Pro Touring market today.”

Scroll to the bottom of the page, our diagrams and their following explanations point out some of the reasons why this suspension surpasses them all. For specific vehicle application and ordering information click the following links...

For more information on your specific application, click the link to your car below.

ExtReme Full Frame systems for '67-'72 C10 trucks are available >Click Here<

ExtReme Subframe systems for '67-'69 Camaros are available >Click Here<

ExtReme Subframe systems for '70-'81 Camaros are available >Click Here<

ExtReme Subframe systems for '68-'74 Novas are available >Click Here<

ExtReme Full Chassis systems for '64-'72 Chevelles will be in production mid year 2016 >Click Here<

ExtReme Full Chassis systems '55-'57 Chevy will be available later in 2016. >Click Here<

For Pre 1955 Hot Rods of all makes click .>Here<

Call 435-628-4300 now for more info or to order yours!

Chevelle Chassis

Camaro ExtReme Subframe

A. Each ExtReme frame is Jig welded in our manufacturing facility in  St. George, Utah, USA. Individual frame rail components are laser cut and CNC formed to ensure consistent close tolerances and are tab-through internally gusseted construction for superior strength. Includes all factory based mounting points for an easy bolt-in installation. 

B. ExtReme frame rails and crossmembers are designed to allow the most available ground clearance with aggressively low ride heights. Run-through, large tubing exhaust ports along with our custom headers keep the entire exhaust above the frame rails.

C. ExtReme CNC formed tubular transmission cross member works in conjunction with engine mounts to help achieving optimum pinion angle. Our adjustable cross member allows a wide range of mounting positions that allows near any GM engine and transmission combination.

D. ExtReme tubular control arms are CNC cold formed and precision TIG welded for superior strength and consistency. They feature ultra high clearance profiles for more steering angle, additional built in caster and camber gain geometry, billet stainless cross shafts with adjustable caster shims, Delrin bushings and performance ball joints.

E. ATS ExtReme front spindles allow any C5/C6 Corvette based caliper to bolt directly on. Rear brakes are based on the popular 9” Ford axle. These types of mounting bosses allow a wide range of brake options, from mild to wild. Speedtech Performance is a direct dealer for both Baer and Wilwood brake systems so we can help customize your brake package specifically to your needs.

F. Performance Rack and Pinion steering systems are standard with all ExtReme chassis and subframe packages.  Rack and pinion offers precision steering with a quicker feel and  better feedback in a lighter weight package.

G. Exclusive to our ExtReme suspensions are race tuned, three piece splined sway bars. This allows each individual chassis or subframe to be custom fit with sway bar spring rates specific to your vehicle and driving style.

H. Race valved Viking Crusader double adjustable coilovers are standard ExtReme equipment. Your choice of spring rate, both compression and rebound valve adjustment, and easy ride height changes allows complete tuneability for street cruising to full race settings. Ridetech and JRI are also available shock options.

I. Better  than any other spindle available, our NEW forged 7075 aluminum ATS ExtReme spindles offer reduced KPI/SAI angle, max Ackermann, virtually ZERO bump steer, up to 30 degrees of steering angle, low scrub radius, heavy duty C7 Corvette hubs, and C6 based caliper mounting.

J. A perfect match to our ExtReme suspension, our Torque Arm is superior to leaf spring and 4 link type systems, allowing the most amount of suspension travel without bind. Our design offers easy ride height, roll center, pinion angle, instant center, and wheelbase adjustability, with more clearance than competitor’s systems.

K. Speedtech Performance’s exclusive Articulink design allows smooth suspension travel without the bind that plagues rigid trailing arms. Standard equipment on all ExtReme suspensions, Articulink control arms are adjustable for correct pinion angle, instant center and wheel location.

L. Exclusive to ExtReme suspensions is the option of a splined rear sway bar. Not only can you order your choice of bar spring rate, the arms have three end link mounting positions for fine tuning the bar to your specific vehicle.

M. ExtReme full chassis systems include a 9” Ford axle housing, large bearing Torino style housing ends and 31 spline axles. Optional 35 spline axles and complete center section are available along with a super strong True Trac posi differential with your choice of axle gear ratio.