Just an update, Kyle and I were talking and came to a conclusion, when most of us say roll center, we really mean center of gravity. Roll center is a whole different animal, that is covered very well in
this article.
On another note, I noticed the Maxima guys are replacing the Russel link bushings with delrin. I thought that was a no no, but someone pointed out that Mike K was actually talking about the bushing that connects to the link body of the car itself. The Delrin bushing should not bind at all.
How To: Install Delrin Rear Beam Bushings + Review!
ES bushing for Axle beam ? - Maxima Forums
Originally Posted by
speedymax99 Originally Posted by
jac121479don't you want big soft rubber bushings in a Scott Russell. i thought the reason for the squishy stuff was to keep the beam from binding causing an infinite spring rate???
You want a bearing that allows the parts to rotate/swing smoothly, that's what this is. There's no binding, which is why I mentioned I could swing it up and down smoothly by hand when installed on the car.
You don't want a big squishy bushing that allows the parts to move side-to-side unwantedly and that doesn't rotate smoothly, but rather twists, adding an unknown spring rate into the equation. Originally Posted by
speedymax99 Originally Posted by
jac121479here's a quote from Mr Kojima, whom i trust when it come's to suspension.
Originally Posted by
MikeTo keep the stock rear suspension from flexing sideways under load, Nissan uses a device called a Scott-Russell linkage. The linkage does reduce flex but the big soft rubber bushings needed to keep it from binding up hinders it. The linkage causes binding and uneven wheel rates from side to side.
I don't think you're understanding or looking at the pictures right. There are 4 bushings back there. Only 1 is made to flex sideways, and that's left alone. 2 are in the link, and these make that link operate much smoother. The remaining bushing is almost too small to replace with delrin/alu and would require a spherical bearing because it moves in more than 1 axis.
Originally Posted by
speedymax99
Originally Posted by
ajm8127Point b is where the bushing goes that allows side-to-side flex. Although this diagram is a simplified version of the linkage on the 4th gen. Notice how it is lacking the extra link at c. I suspect that the addition of this smaller link, the one that is getting the delrin bushings, better approximates vertical motion of the rear beam without inducing as much side to side motion of the beam, or flex in the bushing at b. Less flex = less bind. Point b is on the very right side of this picture:
http://upload.wikimedia.org/wikipedia/commons/thumb/2/20/Scott_Russell_Linkage.jpg/800px-Scott_Russell_Linkage.jpg
Speedymax, are these delrin/aluminum bushings for sale, or are you just trying to generate some interest?
That diagram is actually exactly like our rear beam setup, as view from front to back. It does show the 2 links we have. Imagine points "A" and "C" not being able to rotate freely, but depending instead on a hard rubber to twist. The whole assembly will not move up and down smoothly, but will still move side-to-side because it's rubber. Not what we want.
Be the first to like this post.
Back to top
