Basic Spring Setup Tool

taufikp

taufikp

Registered
I made a little car setup tool, called Basic Spring Setup. This is a browser based tool, because I want to be able to use it anywhere, from my smartphone or tablet.


Basic Spring Setup by simfactor, on Flickr

Some say that it is easier to do initial spring setup based on known natural frequencies for specific car type. Some also say that these frequencies can be used to get good balance between front and rear spring rate. And of course this "math based" setting is purely for basic/initial car setup, after that you still need to do some laps and change some settings, in order to get good car setup.

I created this tool in order to learn (relearning to be exact) car physics, especially the correlation between front spring and rear spring frequencies/harmonics.

How To Use
First, you need to enter:
- weight
- weight distribution front-rear
- lateral weight distribution
- all spring rates

This tool will calculate and show you:
- frequency for each spring
- total average frequency at front and rear
- recommended rear spring frequency

There are three recommended rear spring frequency values: low, medium, and high. Change both rear spring rates (left and right) to mach the recommended frequency you want.

Access the tool from this URL: http://racingtracks.net/springsetup/


Have fun and happy new year 2013 guys!


CHANGE LOG:
- 2013.01.03.04.02, fixing calculation error in recommended suspension rates
- 2013.01.02.09.10, adding spring rates to recommended values
- 2013.01.01.23.48, first version launched

RELATED/SOURCE LINKS:
http://autospeed.com/cms/title_Springs-and-Natural-Frequencies/A_112279/article.html
 
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Nice one. It would be handy to be able to enter a front spring value and have it calculate 3 rear spring rate options based on the recommended frequencies.
 
kaptainkremmen said:
Nice one. It would be handy to be able to enter a front spring value and have it calculate 3 rear spring rate options based on the recommended frequencies.
Click to expand...

Yeah, at the moment you have to enter those values manually to match the recommended frequencies. Well, maybe for the next step, should be easy to compute and show them.
 
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SLuisHamilton said:
Great tool taufik. A lot of thanks coming.
Is it possible to download to pc?
Click to expand...

you're welcome SLuis. As for the download question, while still opening this tool in your browser, right click the page and choose Save Page As... and save it as a HTML file locally.

To run it, you have to open the local file with your browser, just right click on the file, and choose Open With... and select the browser. I've made this tool with simple HTML and Javascript syntax, nothing fancy, so you'll be able to run it offline without the need to install a web server application.
 
lordpantsington said:
Shouldn't you be considering the sprung mass and motion ratio? (Not just corner weight)
Click to expand...

Please bear in mind that this is a very simple spring natural frequency calculator, not a complete suspension solver :D

CarFactory is an example of good suspension solver, since its purpose is to create a complete car.

Actually, I made this tool based on what we see in Garage/Vehicle Setup screen. Dampers (bump/rebound) are not in equation yet, since I have no idea how to get the damper rates from Garage/Vehicle Setup screen. Also I've read from the article in given link above, damper's effect on spring's natural frequency is very small, almost have no effect at all.

So this tool is pretty much solving just a very small part of the much larger/complex suspension system.
 
taufikp said:
CarFactory is an example of good suspension solver, since its purpose is to create a complete car.
Click to expand...

No, it is not. Horribly flawed is what I call K!CF. Generally, the kinematic trends seem to follow, but the actual values are astronomically incorrect. If in doubt, look specifically at roll center analysis.

Anyway, if you didn't know, there is a switch in the ini to give damper rates in the garage (instead of click numbers). If you need some general theory of what to use for rates I have a link: http://www.optimumg.com/technical/technical-papers/ The Springs and Dampers section is a good read for anyone with interest in the subject.
 
Thanks for the link my lord! :D

I'll check it out soon.

Wow, I didn't realize that CarFactory is flawed. When I was using it for the first time, I thought all suspensions produced were excellent, the car was firmly planted to the road and so much stable.
 
I really wanted to trust K!'s numbers. But the car drove so horribly with good numbers that I took a few months and built up my suspension as modeled in rf, in a solid modeling program. FWIW I have only used K! for the analysis tab. Perhaps the issues are isolated to analysis only?
 
lordpantsington said:
Shouldn't you be considering the sprung mass and motion ratio? (Not just corner weight)
Click to expand...

Don't you mean un-sprung weight (mass)?

ie; tires, wheels, brake parts (assuming outboard brakes), suspension parts, and the springs themselves... Anything that the springs aren't "holding up"?

Those would all be contributing parts of the harmonics of the springs. Or am I missing something?

Bryan
 
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It is easy to think of the body fixed in the air with the springs and such doing the work on the unsprung (thus the mass on the oscillating system). But, in actuality the wheels are fixed to the ground and the springs work on the sprung mass. I do have issues remembering which is what at times, and checked the formula from the OptimumG pdf prior to posting. Short answer: nope. :D :D
 
I am curious about the calculation equation used? The output values appear odd? I cannot reproduce the same values as the tool with a hand calculation?

So it appears to me there may be a discrepancy that needs to be resolved!:confused:

I hope taufikp replies. I have also sent him a PM?
 
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