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Discussion Starter #1
Sorry, it is not for sale ;)

I am putting in new opentracker roller perches that I just made (Hats off to John!!). I decided
to make a detailed measurement of the bumpsteer, while the springs were off. I won't go into
detail as to how I measured the BS, but I have a good, repeatable process that I need to write up some time.

What I found was that I can improve the BS characteristics when the wheel is loaded, but at
the expense of worse BS when the wheel is unloaded. In other words, improve BS when the
wheel moves up, but increase BS when the wheel goes down.

So, it seems like there is a range I need to be optimizing for, instead of trying to remove BS
altogether (which I don't think is possible).

Does anyone have an opinion about what range of wheel motion should be optimized to reduce BS?

Here is a chart that shows what I have measured. One set of data is from using no shims on
the Baer kit, and the other uses two shims that move the outer tie rod down about 3/4". I think
using no shims is the best setting for me.

BTW - I have TCP R&P, which supposedly reduces BS. Also have Global West UCA/LCA, and
Shelby drop. Your results may/will be different.

http://home.swbell.net/rwking/bumpsteer_metrics


Randy
 

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Sorry, your chart doesn't show up for me...

Good article here - see section C for corrections.

Most people look for .020 or less toe change per inch of vertical travel. Obviously, less is better, particularly -2" to +1" from static ride height.
 

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You're on the right track. You can't easily remove it, only minimize it.

I would determine the position the suspension is at when at normal ride height. Then use a small range of motion either side of it for my target movement.

You'll love the improvement when you drive it!
 

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Discussion Starter #4
Sorry for the chart problem, it should work now.

I will follow up after I read the article posted by GT350Clone

rk
 

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For the stock geometry guys, I did a similar study comparing the '65 and '71 spindles over at c-c.com

http://corner-carvers.com/forums/showthread.php?t=26792

I haven't had a chance to try out the Baer Tracker kit yet, but it's on my list. Floor repairs have consumed my time.
 

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For the stock geometry guys, I did a similar study comparing the '65 and '71 spindles over at c-c.com

http://corner-carvers.com/forums/showthread.php?t=26792

I haven't had a chance to try out the Baer Tracker kit yet, but it's on my list. Floor repairs have consumed my time.
I'd be interested in seeing your results, however, unregistered users can't view attachments at C-C, and I refuse to register.... ;)
 

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Discussion Starter #7
I saw the same thread at C-C a couple of weeks ago. The call for additional data from other
folks is part of what prompted me to do the precise measurement. I tried to register on the CC
forum, but I guess I was not accepted. Never heard back from them :(

rk
 

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Here are the results of my bumpsteer test on the stock suspension parts.

I tested both a '65 V8 spindle as well as a '71 drum brake spindle. The tie rod height varies between the two, so this is effectively a nice indication of how the Baer Tracker kit would change the bumpsteer (at least directionally).

Here are the results:
http://forums.vintage-mustang.com/forums/photopost486/data/500/3725065_spindle_curves.jpg


Here's my ride height for the 'zero' point. It's a 225/50/15 on a 15x8" wheel for reference.

http://forums.vintage-mustang.com/forums/photopost486/data/500/37250Zero_Height.JPG

This is the Bumpsteer Gauge that I used for the test:

http://forums.vintage-mustang.com/forums/photopost486/data/500/37250Setup.jpg


Here's the Pro-Motorsports Bumpsteer Kit:
http://forums.vintage-mustang.com/forums/photopost486/data/500/37250ProMotorsports_Bumpsteer_Kit.JPG

Here's a picture of the Baer Tracker kit.


I don't have one, so I haven't tested it yet. Interpolating out the effect I saw from the PM kit, the Baer style seems to be the way to go for the '71 spindle with sock suspension components. Comments from others, such as Opentracker have shown that the Baer Tracker kit can pretty much dial out all of the bumpsteer. As soon as I get my hands on a set of them, I'll retest that part and post again.

http://forums.vintage-mustang.com/forums/photopost486/data/500/37250Baer_Tracker_Tie_Rods_136-3261002.jpg
 

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you know this may sound kind of stupid but it looks as if you could use the baer kit along with the pro-m kit and get the advantage of the quicker steering ratio and reduced ackerman of the pro-m kit and also get rid of some of the bumpsteer and use the baer kit to fine tune the rest of the bumpsteer out. of course i could just be talking out my ass too
 
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