tierod location

[TonyTheTiger]

Hey Guys,

In RCVD the author mentioned that the tierods should be mounted at either bottom front or upper rear locations of the wheels. I know this mounting method gives under-steering, which is more preferable than over-steering and it has something to do with the lateral force, but what is the mechanism behind it?

[nowhere fast]

The mechanism is camber compliance steer. Camber compliance caused by the ball joints, a-arm deflection, and chassis deflection will cause the wheels to steer out of the turn (thus understeering) if the tie-rods are placed in those positions. This is assuming the tie-rods and their mountings will deflect less than the a-arms under the cornering loads.

That said; the comment in RCVD was probably directed at road cars with suspension mounted on rubber bushings, and there are other reasons why you would want to place the tie-rods in a different location.

Edit: I should point out that I was referring to the front wheel tie rods/steering rack location since from memory this is what the mentioned section of RCVD refers to.

[Shebert]

I won't tell you to do a free body diagram(but you could), as it can get messy when working with linkage in 3D.

What I suggest you is to do a FEA 3D link model, it allows you to do a first estimate of complience before you done any mechanical design.

It feels good to see peoples that worries about those kinds of things.

Cheers,

[Thomas MuWe]

I would like to add that you must consider for the position of the tierod what's happening during cornering......