C2 Rear Suspension Geometry( missing link)

[Jerry G.]

For you engineering /suspension geeks( I'm one). I am modeling the rear suspension on my 64 race car. I am having trouble finding a missing link. A suspension is free to move in 6 degrees of rotation in space. A suspension by design is constrained in 5 degrees allowing it to work properly. It takes 5 links for a suspension to work. An A arm counts for two, a steering link is one.FYI . I am having trouble finding the fifth link for the REAR suspension. At my count the half shaft counts for two since it contains in both vertical and side to side, The camber rod is one and the trailing arm is another for a total of 4. I know this works, what have I missed?

[Terry M.]

Re: C2 Rear Suspension Geometry( missing link)

For you engineering /suspension geeks( I'm one). I am modeling the rear suspension on my 64 race car. I am having trouble finding a missing link. A suspension is free to move in 6 degrees of rotation in space. A suspension by design is constrained in 5 degrees allowing it to work properly. It takes 5 links for a suspension to work. An A arm counts for two, a steering link is one.FYI . I am having trouble finding the fifth link for the REAR suspension. At my count the half shaft counts for two since it contains in both vertical and side to side, The camber rod is one and the trailing arm is another for a total of 4. I know this works, what have I missed?

Trailing arm is two since it constrains up and down (at the front) and side to side.

[Jerry G.]

Re: C2 Rear Suspension Geometry( missing link)

Up and down at the front i see. but side to side is managed by the half shaft and camber rod. If you remove half shaft and camber rod the trailing arm can move side to side

[Bill M.]

Re: C2 Rear Suspension Geometry( missing link)

Up and down at the front i see. but side to side is managed by the half shaft and camber rod. If you remove half shaft and camber rod the trailing arm can move side to side

The trailing arm removes three degrees of freedom: fore-aft translation, rotation about the halfshaft and rotation about a vertical axis. Take a look at a C4 rear suspension and you'll see the 2 trailing links and toe link that replace the trailing arm. That's how I see it.

[Jerry G.]

Re: C2 Rear Suspension Geometry( missing link)

Wow this is messy. Reminds me of static and dynamics class in engineering school. I just talked to Bill Mitchell who is a suspension"Guru" and wrote the software. He went over Zora's SAE paper on this and has suggested that the trailing arm does indeed impose three degrees of restraint. It acts as three links. All three begin at the pivot point in the front of the trailing arm. Two terminate at the axle hub, one above and one below the axle centerline. The third terminates at the hub but is INBOARD on the Y axis of the hub carrier. The other two links are the 1/2 shaft and the camber link. I'm going to put this into the suspension design program and see what pops out. This discussion has been very helpful for me. Thank you.