Converting Single A-Arm to Double
Converting Single A-Arm to Double
I'm new to this forum, but I have read a few of the posts and found your information helpful. So I decided I would attempt to have my own question answered here. Currently, the vehicle I am working on has a rear suspension design similar to this (I apologize in advance for the very basic "paint" drawing):
It is a basic rear suspension with a single a-arm. The spindle is attached to the lower control arm and a macpherson strut which is mounted to the frame. The tie rod is mounted to a lower cradle (mid engine)and then to the spindle. Hopefully that picture depicted it well.
I would like to modify the suspension so that the result is something like this:
This suspension is a double a-arm design with a shock replacing the strut in the original configuration. The lower control arm remains exactly the same and the spindle mounting point for the tie rod remains the same. The rest I'll explain. The supports (purple lines) are coming from the cradle because at the moment the cradle is not solid mounted to the frame. If I am going to add another a-arm, I'd rather it not be solid mounted while the other is under possible influence from the cradle shifted on it's mounts. A simple way to counter that is solid mounting the cradle, but as I need to be able to drop the cradle to perform engine work, I can't just weld it in. I plan on using aluminum bushings to make it as solid mounted as I can, but if there is even the slightest movement, I'd like both a-arms to be under that influence. The spindle will be attached to the upper control arm in a way that will allow it to rotate. The tie rod is leading to a steering rack as I would like to eventually add some sort of four wheel steering system. All the other components are already set up for this, but the use of the strut in the original configuration doesn't allow for movement of the spindle. So that just leaves my questions.
1.) Is it possible to do this and retain the suspension geometry that was the original design? If so, what are the critical things that I should do to retain this? I'd like to improve the geometry if there's room for it, but it's far more important to have at least the same geometry after this endeavor.
2.) In the original design, the camber adjustment is made by the bolt linking the spindle to the strut:
What do I need to do to retain this adjustment point?
The purposes of this redesign are to improve handling characteristics. The overall goal is add in the four wheel steering design, but before designing the four wheel steering system I'd like to ensure that the attachments themselves will work before the system is added. Even if the four wheel steering cannot be developed after this is added, it would allow me to have the same style of suspension in the front and rear. Also allowing my to use the same dampening equipment at all four corners of the car (the front suspension is a double a-arm with a shock so I could just gather four of the same shocks for suspension parts). I'll be the first to admit that I don't have an extended knowledge of suspension design so I'll take your advice and criticisms openly, however if you are giving either, please explain the reason for giving it. Also, if you notice something that I have not considered, please let me know. If you even read this far, thanks already for your attention. I appreciate any help I can get.