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Old 07-15-2019, 11:45 AM
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phantomjock phantomjock is offline
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Exclamation Suspension Tools

Not the ones you buy from Snap-On. Computer Aided Tools!

I have posted a few Excel files to the DOWNLOADS section. I came across these in one of my quests for “easier, simpler, cheaper” methods for suspension analysis. As luck would have it, I found a most comprehensive set. Luckier still, they are built around a C3 Corvette modification project!

Coincidentally, the owner of the webpage is based in Sarawak, Malaysia. Recall I spent over 10 years off-and only a few hundred miles away on my boat. Had I known then; I would have taken the opportunity to connect with him in person. I have reached out several times but have not been successful in getting an email through to him. Never-the-less, I have reaped his files and provide him appropriate attribution, here and on the files.

Bill Harbin is the Technical Director of BND Techsource. He has made a nice webpage as well and encourage all those interested to take a run over there and check it out. His C3 project involves a Tube frame, with C4 rear suspension and C5 front setup. These spreadsheets are available as Imperial or Metric. His spreadsheets cover:

MASTER PAGE – All entries made here carry to the appropriate pages
CENTER OF GRAVITY (height) – Process description and Table for Calculations
SPRUNG UNSPRUNG WEIGHT – Table for entries [Could be expanded to calculate these weights by individual components. I’ll do as I have some time]
FRONT and REAR TIRES – Tabular entries linked to following pages for calculations
DAMPER RATE CALCULATOR - self explanatory
ROLL CENTER AXIS – Includes Jacking Force Calculations
ROLL RATE/ROLL STIFFNESS – Includes tables for calculating
ANTI-ROLL BARS – Size, length, Angle of Bend, Bushing Calculations
CAMBER and TOE (DESIGN) – Includes service manual details
TIRE SLIP ANGLE – Includes 300ft Skidpad @ 1G sample calculations
TIRE GRIP – self explanatory
CAMBER THRUST – Discussion and some calculations
STEERING MOMENTS – Focused on Rack and Pinion
LATERAL LOAD TRANSFER AND BODY ROLL CALCULATOR – Calculates Vertical load on wheels and analyzes tire adhesion
STEADY STATE CORNERING – Analyzes inside/outside tires (2 TABS)
GILLESPIE – BUNDORF ANALYSIS – Analyzes CONTRIBUTIONS TO Understeer from various sources
There is a "Cover Page" that is kinda' a Work-Breakdown sheet. Lets you track What/When/Who for the project. Color coded symbology can let you see what you have left to complete. Adding a Bill Of Materials (BOM) would be quite useful, and a comprehensive table for summing up the components used in UNSPRUNG WEIGHT Calculations (I'm working on that.) The document is missing a comprehensive BRAKES Section. I'm looking for more there too.

Meanwhile, I have included a copy of his BRAKE FORCE CALCULATOR, at “no extra charge…”

Also, on his site he has several useful supporting texts, PowerPoint Presentations on Load Transfer, and much more information useful to us. Hopefully others here will find them equally useful. His page is at:
[Only registered and activated users can see links. Click Here To Register...]

I have also added a copy of a very comprehensive Suspension Geometry Textbook by John C. Dixon. You may have to dust off your Calculus book - but I said, "It is Comprehensive!"

Hope you find these useful. I'm using a number of these tools just now and if there is a problem will cover it here.

Cheers - Jim
Rebuilder's Zen Saying:
One thought leads to another. If these thoughts link into a chain we become bound to the project. This bondage is subtle and remains until we complete the tasks -- or, STOP Thinking!
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Old 07-15-2019, 02:48 PM
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BBShark BBShark is online now
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I was looking for information on static tire radius (and its influence on ride height) about 5 years ago. I searched every where and the only information I could find was on that site. I think he even has a calculator for static radius based on tire size.
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Old 07-17-2019, 09:43 AM
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OZgreen69 OZgreen69 is offline
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Thanks, much appreciated.
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Old 07-17-2019, 07:03 PM
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phantomjock phantomjock is offline
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Free is cheaper than the Performance Trends and other tools out there.

You'll note the x and z axis conventions are based on the front axle (x + is forward) and ground (z + is up.) Clever persons might be able to build some visual depictions like in the [Only registered and activated users can see links. Click Here To Register...] or the Performance Trends models.

But, free goes a long way. For me, it almost justified buying RHINO for CAD. I am researching pushing the data points into Rhino. Would be a nice addition.

Cheers - Jim
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