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Old 04-06-2009, 07:36 PM   #1
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Default Roll Centre and Camber Gain Calculator

To relieve the boredom of a long winter I decided to teach myself Visual Basic. The result is an interactive program that calculates Static Roll Centre and Camber Gain for virtually any sedan suspension. Suspension models for the JRXS R are already in the database but the program will work for any car. I just takes a little time and some accurate measurements and you can model the suspension on your car.

There are two main pages in the program, a setup page and a model page. The setup page graphically displays side by side a scale picture of the front and rear suspension. To change the setup just click on the alternate positions in the graphic and the new roll centre and camber gain value is calculated.

The Model page is where models are created, edited and deleted.

Attached are pdf's of these two pages.

If there is any interest I'll try and upload the file to a FTP site. If anyone knows a good one let me know.
Attached Files
File Type: pdf Setup Page.pdf (166.3 KB, 3090 views)
File Type: pdf ModelPage.pdf (166.0 KB, 2189 views)
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Old 04-06-2009, 08:04 PM   #2
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Which cars would this work for?
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Old 04-06-2009, 08:18 PM   #3
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Any car with a double A arm (sedan) type suspension. Won't work for pan car suspensions if that is what you are looking for.
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Old 04-06-2009, 09:08 PM   #4
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I uploaded the program to a file hosting site for those who want to try it.

To install after download open the zip file and click on the setup file to start the installer. If you do not have Microsofts VB.net or SQL databae server on your system then the installer will download and install them if you agree. The program will not run if you don't install them.

I've installed it on both XP and Vista OS.

Here is the link.

http://www.mediafire.com/file/4m4tgm...CentreV162.zip

Last edited by BobW; 05-29-2009 at 09:59 PM.
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Old 04-06-2009, 11:16 PM   #5
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BobW, thank you for sharing. It's way cool!!!!! It going to be interesting to start using this as a tuning tool. Thanks again!
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Old 04-07-2009, 05:42 AM   #6
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So it installed and ran without any problems. That's great!!!!! This is my first attempt at creating and sharing something like this. I would love to build up the database with models for every car. If you build a model for something besides the Losi I would love to have the numbers.

If you find any bugs or have suggestions for improvements please post them.
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Old 04-07-2009, 05:49 AM   #7
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Man you really must have been bored to learn VB, not my first choice for a programming enviroment/lanuage.

great programme i'm sure alot of people will be interested in it and will find it usefull.
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Old 04-07-2009, 05:55 AM   #8
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Learning VB was definitely a challenge. I almost threw in the towel a couple of times. Took me three months and several thousand lines of code. I'm sure if a trained programmer looked at my code they would have a good laugh. It does seem to work though.

Thanks. Hope it helps.
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Old 04-07-2009, 04:31 PM   #9
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How do you find the CG? Could it be added to the software?
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Old 04-07-2009, 05:40 PM   #10
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Old 04-07-2009, 06:41 PM   #11
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Hi Bob,
great little program.
One thing I have noticed is that I don't think you can set your front and rear tires to different widths. (It is quite common where I race)

Now all I need is some to explain what it all means and how I can use it to help me setup the car.
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Old 04-07-2009, 11:24 PM   #12
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Thanks guys for your comments. I’ll do my best to answer your questions.

4WheelDrift, Calculating the location of the CG would be an enormous task, it’s much easier to measure it. Finding the front to rear and side to side location is easy just find the point at which the chassis balances. Finding the point where it lies from the bottom of the chassis is more difficult. I would think some sort of jig that would allow you to hold the car and find the point when the chassis hangs perpendicular to the ground would be the easiest solution.

Mark506, It’s looks like the program crashed or exited prematurely. The only suggestion I have is try again. Others seem to install it OK. It make take a while for the Microsoft Apps to install so you may have to be patient. I know it took a while when I installed it on my laptop with Vista.

Fatbear, Yeh I didn’t include different tire width option for front and rear. I don’t think it should make a huge difference though. Just make two models, one with each tire width and see what the difference is. I'll keep this in mind for future upgrades.

As far as setup is concerned in very simple terms the lower the roll centre the more grip and the more camber gain the more grip. Obviuosly there are limits to how much grip you need and sometimes you need to go the other way and reduce grip. The best advice would be to get a good setup book like the XXXMain Setup Guide and read it, then read it again, and again. Well you get the idea. You can find the book here:

http://www.xxxmain.com/bookz.shtml
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Old 04-08-2009, 01:01 AM   #13
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If any one does these measurements for an Mi3 pls post it and for any other car to help others that would be cool
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Old 04-08-2009, 03:12 AM   #14
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Thanx for this little program. D/L and installed and it looks like I have found an explanation for my lack of rear grip on transition. Should be able to fix that now.

Was trying to work out how to add a 1mm shim to the outer ballstud for the upper arm at the rear. I have looked and looked but can't work out how to put it there. Do I need to move the piviot points somehow instead?
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Old 04-08-2009, 05:54 AM   #15
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Quote:
Originally Posted by Dragonfire View Post
Thanx for this little program. D/L and installed and it looks like I have found an explanation for my lack of rear grip on transition. Should be able to fix that now.

Was trying to work out how to add a 1mm shim to the outer ballstud for the upper arm at the rear. I have looked and looked but can't work out how to put it there. Do I need to move the piviot points somehow instead?
Go to the model page and select the "Rear Suspension" radio button and then click on the "Alternate Outer Positions" button this will open a window where you can enter other positions for the outer camberlink. These positions are entered as offsets from the base point so a 1mm shim would have a horoffset of zero and a vertoffset of 1.0. A 1 mm shim is pretty small so it may be hard to click on it in the setup page. The other way to do it would be to increase the value for LKing on the model page by 1mm.
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