Performance Trends, Inc.

Producing Quality Computer Tools for Racers and Engine Builders since 1986

Shock Dyno

Complete Shock Absorber Tester/Dyno System, or Computer Program and Electronics as Retrofit Kit

for Windows XP, Vista, Windows 7, Windows 8, Windows 10



for pictures showing how powerful our shock dyno is.


Our Complete Shock Dyno features include:

  • 1.5HP, 110 VAC motor (ideal for most trailers and generators).  220 VAC 2.0 HP option available.
  • Stroke is adjustable for 1 and 2 inch strokes.
  • Up to 14 inch/second shock velocity. 
  • 2000 lb load cell.
  • With standard 36 inch masts and 2 inch stroke and the load cell adjusted to maximum height, the eye to eye distance of the shock will cycle between 23 inches to 25 inches.  Obviously you can lower the load cell to any distance less than that.  Mast extensions are available to accommodate longer shocks.
  • Can handle forces over 1500 lbs and more. 
  • Optional shock temperature sensor, and warm up procedure before testing. 
  • Optional Plus version of Shock Dyno software with several advanced features.
  • USB computer interface.
  • Safety Shutdown if Max Force is exceeded.
  • Software compatible with Win XP, Vista, Win 7, Win 8, Win 10.  See features listed on this page.

We also offer the sensors, electronics and software as a "retro-fit" kit for your existing shock dyno, described at bottom of this page.


Overlay Graph of 5 Shock Tests (+ and - velocity), with Cursor to Pin Point Values



The Shock Dyno Retrofit Kit provides a load cell and length sensor, plus electronics to record both channels.  Once data is recorded, you can create reports or graphs of the results.  You can also overlay graphs from several different shocks for comparison.

Graph with just + Velocity


The program has several options, including:

  • You can graph results either absolute velocity (typical of most shock dyno programs) or versus velocity with direction.  This 2nd choice lets you pin point differences on the graph more easily with the cursor.

  • Modern USB electronics for easy installation on newer computers.

  • Overlay plots for comparison.

  • Infra-red (non-contact) temperature sensor (optional with Plus software).

  • Start testing immediately or when a user selectable temperature is reached (temperature requires Plus software).

  • Summary of results as shown below, for max Compression  and Rebound force, Stroke, RPM, Test Cycles, Average/Max/Min temperature, etc.

  • Programmed or user selected test time.

  • Over-Force shutdown safety.  If the system detects a force greater than user selectable limit, the motor is turned off.  This can happen if you install the shock incorrectly.

The program is compatible with Windows XP, Vista, Windows 7 or Windows 8, which means it is easy to use and you will be able to print the results on most any printer, usually in color if your printer supports it.



  • 24 x 16 inches x 12 inches high.
  • 165 lbs
  • Standard "masts" extend 36 inches above dyno enclosure.  With standard 36 inch masts and 3 inch stroke, the eye to eye of the shock will cycle between 22.5 inches to 25.5 inches.  At 2" stroke it will cycle from 23 to 25 inches, at 1" stroke it will cycle from 23.5 to 24.5.  Obviously you can lower the load cell bracket and shrink all these lengths down to zero.
  • Mast extensions available to accommodate longer shocks, typically in 12 inch increments.


Plus Version of Software:

The software provides for an optional Plus version, which adds several features:

  • Allows for temperature input, and for triggering recording to start at a particular, user selectable temperature.  This provides for better test repeatability.
  • Additional graph types including:
    • Force vs Velocity Loops (which will show hyseresis in the shock, very useful for troubleshooting problems in the shock)
    • Force vs Position (sometimes called "football graph")  See picture below.
    • Velocity vs Time (good for troubleshooting system)
    • Force vs Time (good for troubleshooting system)
    • Position vs Time (good for troubleshooting system)
    • Position vs Time - Raw (good for troubleshooting system)
  • "Real Time Graphing" prior to recording, so you can spot that the results will be what you expect.   See picture below.
  • Company Logo appears on main screen also, in addition to printouts.

Real Time Graphing - Green dots are current readings, black lines are from previous test


"Football" graph of Force vs Position for 2 different shocks



Some customer's have asked how results on our dyno compare to other dynos.  Most people consider the Roehrig tm dyno the industry standard.  We ran a couple shocks on our Performance Trends dyno and a Roehrig 3VS dyno and the results are displayed below.  I think you can see that our dyno produces the nearly same results as the Roehrig, and the difference could be easily explained by the small differences in shock temperatures.  When you consider the Roehrig tm costs about 3 times as much as our dyno, we definitely offer the best testing value.  

Performance Trends Dyno - QA1 shock tested at 93 deg (produced with v1.1B Plus software)

Performance-Trends-QA1.gif (27236 bytes) (click image to enlarge)

Roehrig tm Dyno - QA1 shock tested at 73 deg

Roehrig-QA1.gif (38650 bytes) (click image to enlarge)

Performance Trends Dyno - Penske shock tested at 102 deg (produced with v1.1B Plus software)

Performance-Trends-Penske.gif (25068 bytes) (click image to enlarge)

Roehrig tm Dyno - Penske shock tested at 80 deg

Roehrig-Penske.gif (36658 bytes) (click image to enlarge)



People sometimes wonder if a 1.5 HP motor is strong enough for testing some of the high rate shocks used in current circle track racing.  The graph below is for a JRI shock on the left front of a CRA Super Late Model, at 2 different and relatively high rebound settings, 7 and 9.  You can see we are easily measuring almost 2000 lbs at about 6"/second velocity.  We also have the 2.0 HP 220 VAC motor option for even higher performance.


Here's a picture of what happened to one of our shocks we used to test the durability of our Shock Dyno design.  Yeah, we're tough.

Shock-Dyno-Broken-Shock-HiRes.jpg (226212 bytes)  click image to enlarge


What You Need:

Computer with Windows XP, Vista, Windows 7, Windows 8, Windows 10. 


What You Get with the Retro-Fit Kit:

  • Shock Dyno v1.1 Software
  • Quick start documentation.
  • DataMite Mini USB data logger/electronic recorder.
  • 1000 lb "S" beam load cell, with optional ranges from 100 to 5000 lbs for nominal charge.
  • 3" length/position sensor, with other styles, sizes and lengths available for nominal charge.
  • USB Cable (which also powers system, no power supply needed).
  • Temp Sensor Optional
  • Shut Down Relay and Cabling Optional

The shock dyno kit expects your dyno to use a slider crank (like piston in an engine) or Scotch yoke design to cycle the shock, but does not need a variable speed motor.  We very accurately measure the speed of the shock as it goes through its cycle up and down.  When it is at the top of its cycle, it has stopped and then changed direction to go back down.  As it goes back down, it picks up speed to maximum speed at mid stroke, then slows down when it gets to the bottom of the cycle.  Then this whole process is repeated in reverse.  

So, as the motor turns at a constant RPM, we can measure the velocity and force at all points of the cycle, and produce a complete shock dyno graph with force at all velocities. This makes it very easy for the electrical motor, just set it to something like 150-300 RPM with a 1" to 3" stroke, get it up to speed and press F1 on the keyboard.  The software records several cycles and then presents the data.

Jim Butcher's do it yourself (DIY) Shock Dyno built from a small engine with our retrofit kit
Jim-Butcher-Shock-Dyno.jpg (184636 bytes)
  Jim-Butcher-Shock-Dyno-2.jpg (212707 bytes)  click images to enlarge



SDyn-SSAK  Three piece "Adapter Kit" for mounting production style shocks on the shock dyno.  Kit handles top stud/bottom cross bar type of front shocks, and top cross bar/bottom bolt hole rear shocks.

  Shock-Dyno-Adapter-Kit-2-Bolt-Mount.jpg (102613 bytes)  Shock-Dyno-Adapter-Kit-Stud-Mount.jpg (110036 bytes)  Shock-Dyno-Adapter-Kit-Through-Bolt-Mount.jpg (112708 bytes)  click smaller images to enlarge


SDyn-IR  Shock Dyno infrared (non-contact) temperature sensor with bracket.  If you order the retro-fit kit, we typically sell you the DT2-IRA, which is the same sensor but without the bracket.


More Information, Movies, Download Demo:

for some movies on setting up and operating the shock dyno Shock Dyno Movies.

to download a FREE Shock Dyno Demo.

to download the preliminary Shock Dyno's User Manual.


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for pricing.

for financing info on paying on installments.

To email us for a quote for the system to meet your needs  to send us an email.

To Order:

Call 248-473-9230. Visa and Mastercard accepted. Performance Trends can provide you an "unlocking code" number to activate all features (bring it out of demo mode). When newer versions are released, you can download the latest demo and activate all features with this same "unlocking code".

The "on screen" help explains all features, inputs and outputs.