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Old 03-25-2008, 09:03 PM   #1951
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Old 03-25-2008, 09:19 PM   #1952
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A proper suspension of the front of a pan car intended for asphalt is not a little much. I have heard good things about the HPI front suspension on this thread.

I made a sketch. Adding 3 degrees of negative camber lowers the roll center .25 inch. Getting the same result with the upper a-arm requires changing the inboard pivot .25 inch in height. Now on the oval car I am using about 1.-2 degrees positive camber on one wheel. That is raising the roll center which is not my intent at all. This is not just a "little change".
I use windtunnel springs. The large cylindrical ones
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Old 03-26-2008, 04:08 AM   #1953
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Old 03-26-2008, 06:36 AM   #1954
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Old 03-26-2008, 10:43 AM   #1955
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Here is the sketch that I made on roll center change for the inverted strut Associated front suspension. The roll center change is indicated by the 1/4 inch markings near the bottom. The instant centers are off the page to the left.

The roll center on a twin A-arm suspension are adjustable in a predicatable way. Some guys that run touring car foams make roll center adjustment as they wear the tire. There is no problem shimming this suspension up if that is your desired way of setting ride height.

When I get an Associated front suspension, the first thing I do is go to lefthander-rc.com or RC4less.com and buy about $60 worth of stuff to make it work on outdoor asphalt. This includes
longer kingpins
kingpin shims
teflon coated pivot balls
long springs and spring buckets
(some guys get the inline axles and steering blocks)

Then you spend time trying to make the suspension smooth. It is not at all smooth out of the box. You trim eyelets and steering blocks. OK now it works pretty good, but it still makes the car fly at speed over the bumps because there is no shock.
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Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-inverted-strut-roll-center002.jpg  

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Old 03-26-2008, 11:32 AM   #1956
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Quote:
Originally Posted by John Stranahan View Post
Here is the sketch that I made on roll center change for the inverted strut Associated front suspension. The roll center change is indicated by the 1/4 inch markings near the bottom. The instant centers are off the page to the left.

The roll center on a twin A-arm suspension are adjustable in a predicatable way. Some guys that run touring car foams make roll center adjustment as they wear the tire. There is no problem shimming this suspension up if that is your desired way of setting ride height.

When I get an Associated front suspension, the first thing I do is go to lefthander-rc.com or RC4less.com and buy about $60 worth of stuff to make it work on outdoor asphalt. This includes
longer kingpins
kingpin shims
teflong coated pivot balls
long springs and spring buckets
(some guys get the inline axles and steering blocks)

Then you spend time trying to make the suspension smooth. It is not at all smooth out of the box. You trim eyelets and steering blocks. OK now it works pretty good, but it still makes the car fly at speed over the bumps because there is no shock.

You don't have to conform me to your opinions. If what you write makes sense I will conform automatically.

Could you point me on any links to read up about setting up the AE 12th scale for asphalt? I'm a newbie at this and having problems with bumpy asphalt tracks
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Old 03-26-2008, 11:34 AM   #1957
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Old 03-26-2008, 11:35 AM   #1958
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Old 03-26-2008, 11:37 AM   #1959
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Old 03-26-2008, 11:39 AM   #1960
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No, don't get the wrong idea, i'm not jumping in the ring here. Just that I'm reading up as much as i can about setting up 1/12 for low traction/slightly bumpy asphalt, so any links would be helpful.
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Old 03-26-2008, 02:27 PM   #1961
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You are figuring the roll center wrong.
Nope, that is how you find the roll centre for a macpherson strut.

After some searching around I didn't find a conclusive answer to whether the method needs to be changed at all when the strut is inverted, I doubt it does.

So if you have some info somewhere that says it IS changed then please enlighten us..
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Old 03-26-2008, 02:41 PM   #1962
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John check the design in the picture, it's a patent I came across that is designed to overcome some of the shortfalls of macpherson struts. Not worth using on an rc car as double wishbones can usualy fit in, but interesting anyway.

Rocker strut patent
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Old 03-26-2008, 03:33 PM   #1963
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Old 03-26-2008, 03:38 PM   #1964
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Old 03-26-2008, 03:56 PM   #1965
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That link tells me nothing I already didn't know, also it deals with double wishbone setup, which the AE front end is not, it is an inverted strut, the bottom arm is fixed.

I just did a rollcentre drawing myself and going from 0 to 3deg camber did indeed move the R.C. about 5.5mm, in fact it moved it below ground, I was skeptical myself at such a big R.C. change at first but I confirmed it.
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