3 link and a strange phenomenon.. I think.

[lowbuckex]

I built an Offset 3 link on my Nova. Which can be seen here in an old Post 3 link Lowbuckx style.
My father died and I lost interest for a few years but now Im back on it and got it running and almost road worthy.
Here is the strange thing happening. When I get into the throttle hard at low speed and break the tires loose only the right side is leaving marks. But both tires are spinning. It tracks straight and pulls very hard. But only the right leavs marks. The upper link is offset to the right.
What do you think?

[Peter Mc Mahon]

Do you know that both tires are spinning? I would setup a camera to watch the back of the car during a launch to see what the body is doing relative to the differential

[raustinss]

yep ..... wondering if the differential might be toast. what are the details on the rear end?

[Ron Sutton]

I built an Offset 3 link on my Nova. Which can be seen here in an old Post 3 link Lowbuckx style.
My father died and I lost interest for a few years but now Im back on it and got it running and almost road worthy.
Here is the strange thing happening. When I get into the throttle hard at low speed and break the tires loose only the right side is leaving marks. But both tires are spinning. It tracks straight and pulls very hard. But only the right leavs marks. The upper link is offset to the right.
What do you think?

You don't say how much the toplink is offset ... nor what the rear track width is ... which both matter. Please drop those specs on us.

[lowbuckex]

I do not have those numbers written down. Lost alot after my dad died. But I did use software I got from someone on this site. Cant remember. Think his name was Shope maybe. Ah its been to long.
As for the rear it is a new Eaton unit with less than 100 miles. When I brake tourqe it they both leave marks. Just from a moving start it leaves one. But the slight fish tail is tellig me both are going...

[Ron Sutton]

I do not have those numbers written down. Lost alot after my dad died. But I did use software I got from someone on this site. Cant remember. Think his name was Shope maybe. Ah its been to long.
As for the rear it is a new Eaton unit with less than 100 miles. When I brake tourqe it they both leave marks. Just from a moving start it leaves one. But the slight fish tail is tellig me both are going...

Sorry to hear of your Father's passing. It's a special relationship Dads & Sons have. When my Dad died, it changed my business career direction.

I'd recommend checking the posi, as the other fellas have suggested.

[ford396]

If both tires are spinning, the mark left by only one tire is more than likely due to the loading of that tire more with the offset third link. As you move the link to the right, the load will move with it.

Bob

[raustinss]

also maybe ron will chime in here again ....shock and spring rates ....? that would also have something to do with this yes ?
are they a matched set left to right . i.e same spring rates

[Ron Sutton]

Hey guys, I don't know what the problem is with this particular car, because I don't have enough information.

But in general, under power on corner exit ...
* All linkage style rear suspensions ... 4-link, truck arm, torque arm, centered 3-links, etc ... load the left rear tire 8-13% more than the right rear.
* If we offset the top link of the 3-link ... the correct amount ... the left rear tire & right rear tire will see the same load.
* If we offset the top link to the right too little ... we will get the tire loading closer than 8-13% ... but still not equal.
* If we offset the top link to the right too much ... we will load the left rear tire more than the left rear.
* If the spring rates are different side to side ... this will cause different tire loading side to side.
* If the springs are mounted differently side to side ... the effective wheel rate will vary from side to side ... and this will cause different tire loading side to side.
* If the shocks are not valved the same side to side ... this will cause different tire loading side to side.
* If the Watt's link is off center ... this will cause different tire loading side to side.
* If the panhard bar is level ... this will cause slight different tire loading side to side.
* For a panhrad bar to load the tires evenly, the side that mounts to the housing needs to be a little lower. The actual amount depends on how much roll angle the car has. Getting this dialed in is called "Balancing the panhard bar."
* If the panhard bar is out of balance ... this will cause different tire loading side to side. The more it is, the greater the effect.
* If the car's corner weights on the LR & RR are different ... and this will cause different tire loading side to side.

I'm sure I missed some things. Just trying to contribute to the discussion.


:cheers: