Performance Trends, Inc.

Producing Quality Computer Tools for Racers and Engine Builders since 1986

Circle Track Analyzer v3.6 for Windows XP, Vista, Windows 7, Windows 8, Windows 10

Computer Program to Simulate, Setup, Predict and Analyze Race Car Performance (including Late Models, Modifieds, Sprint Cars, Midgets, Go Carts, etc.) on Oval Track.

for list of new features in Version 3.6 (Mar 2009).

for list of new features in Version 3.5 (Jan 2006).

for a table comparing Circle Track Analyzer with our other Suspension Analysis programs.

New Suspension Analysis Screen features in v3.6

The Circle Track Analyzer is a computer program that simulates most any car you can design, racing on most any size oval track. It will let you predict and understand the effects that various modifications have on handling, performance and lap times.


  • Mouse driven interface compatible with Windows 98/Me/XP/2000/NT/Vista

  • Full 32 bit version uses long, more descriptive names for saving files.

  • Detailed front suspension layout screen, very similar to our popular Roll Center Calculator.

  • Detailed rear suspension layout screen.

  • Many specs can be picked from general descriptions, rather than from detailed engineering specs. However, engineering specs can still be entered.

  • On screen help by simply clicking on any input spec.

  • New graphing features let you graph MPH, acceleration rate, engine RPM, just like a data logger used by the pros. Options include graphing up to 6 tests, zoom, shift, modify titles or labels, different background colors, line styles, etc.

  • A log of the last 25 runs is kept to track your modifications. You can select runs from the log to keep longer to recall or graph in the future .

  • Loads power curves automatically from the proper versions of Engine Analyzer.

  • Print most all menus and screens.

  • Feature to automatically find the best gear ratio for a particular track.

  • Program can automatically "dial in" critical specs to match your car’s lap times.

  • "Corner Jacking" Screen to estimate the change in ride height and corner weights from adjusting (jacking on) springs.




V3.5 added these features:

  • You can now do an Symmetric Angled 4 Link rear suspension, like a Chevelle or Mustang.

  • You can create tables of Roll Center Position and Camber for various combinations of dive and/or roll

  • You can Graph the output from the Roll Center Position or Camber table above

  • Program now calculates Tire Track change (scrub) and draws tires correctly for this change

  • Program now calculates a " Handling Rating" based on the weight transfer of the front versus the rear.  The car is "balanced" at the apex of the turn (not accelerating or braking) when theses weight transfers are equal.

  • The program can automatically find the roll center heights or Spring Rates or front roll bar rate to produce various balances between the front and rear weight transfer.

  • The "Corner Weight" (virtual scales) now determines the ride height and/or corner weigh changes from changing a tire size or moving/removing/adding weight (ballast).

  • Swing Arm length calculation has been added to the Front Suspension Screen.

  • You can link to our Circle Track Log Book.  The log book is for record keeping of all your car's settings.  With the Log Book linking to the Circle Track Analyzer v3.5, you can also keep records of calculated parameters like Roll Center (static and dynamic), Balance, Camber Gain, and more.



V3.6 added these features:

  • You can now included a rear anti-sway bar, and have the program make handling suggestions about it's size.

  • You can now specify separate front and rear aerodynamic lift coefficients.  This lets you see how adjusting aero affects can affect handling.  A special 'Clc' screen lets you estimate some aerodynamic adjustments, like rear spoiler angle and design adjustments.

  • You can now optionally enter more details about the front suspension layout for Double A Arm and McPhearson strut suspensions.  These details better locate the exact frame mount for the A Arms and/or struts, and will calculate Anti Dive (a suspension tuning parameter).  Click on blue link for a pic of these front suspension layout details.

  • Oversteer/understeer rating to estimate the handling of the vehicle at any corner on the track.  This calculation is more detailed than the Front Lateral Load Distribution handling calculation discussed above because it includes corner weight effects, aerodynamic downforce, and accelerating and decelerating weight transfer.  Click on blue link for a pic of these Oversteer/Understeer rating calculations.

  • You can now get suggested starting point adjustments for a Big Bar Soft Spring setup.  The program continues to also give Traditional starting point suggestions.

Additional Optional Front Suspension Details Screen in v3.6

What You Need:

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

What You Get:

Program CD with 200 page manual on CD in PDF format, many example vehicles and components preloaded.

More Information, Download Demo:

to go to our Demo Downloading page to download a FREE Circle Track Analyzer Demo. This demo also lets you evaluate our smaller Roll Center Calculator programs.  When you start the demo, it asks if you want to see just the Roll Center Calculator, Roll Center Calculator Plus or full Circle Track Analyzer.

to view PDF file of Circle Track Analyzer User Manual Supplement of v3.5's and v3.6's new features with Adobe Acrobat (tm).

to view PDF file of Circle Track Analyzer User Manual with Adobe Acrobat (tm).  User manual is v2.0 manual + v3.2/v3.5/v3.6 supplements as Appendix 3, 4 and 5.

to view the Suspension Analysis Programs Comparision Table that compairs the Circle Track Analyzer with our other Suspension Analysis programs.

To Order:

Our DOWNLOAD ONLY option. If you only want the unlocking code and DO NOT want a CD shipped, click on Add to Cart below. You will not be charged shipping.


If you want a CD shipped to you, click on Add to Cart below. There will be shipping charges added to your order. You can still download the demo and get your unlock code sooner with this option.

$169.95 plus shipping

To order a CD with a PRINTED manual, click on Add to Cart. Manuals are included on the CD's but in PFD format. You can still download the demo and get your unlock code sooner with this option.

$199.95 plus shipping

Call 248-473-9230. Visa or Mastercard accepted.

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