DESIGNING MY OWN CROSSBAR! need help

[rob323]

Originally Posted by Sabretooth

Well all the guys who built cages so far, haven't actually mounted them on the rear shock tower, they are mearly welding to the unibody before the shock tower

Yep, if the dropkick that did our cage had done it as we had asked, it would have attached directly in front of the top of the shock, not over on the wheel arch.


Luckily for us, the rear torsion beam suspension design (with shocks, not struts) means that it's not a problem and still works as it was originally intended to work.

So I think your in for a bit of trial and error finding how to mount onto the shock tower.

Echo's have a semi decent mounting point on the top of the shock tower (between the shock tower and the sides), does the Yaris? If so, use that.

But, you say you want to stiffen it. What do you want to stiffen, and in what direction?
The typical cross braces (from upper seatbelt points to floor etc) stiffen the upper rear of the body to the floor pan, but that means it puts more torsional forces on the floor pan (which is where your rear torsion beam mounting points are).
We did not attach to the upper rear part of the body to anything for 2 reasons.
1 - We don't care if that area flexes as it doesn't affect suspension geometry or anything else.
2 - We would prefer for that area to flex by itself rather than transferring those forces to the floor pan and making the floor pan have to work harder to resist them.

(off topic - I found a surprising amount of play in the rubber bushes in the top of the rear shocks and I expect the Yaris would be the same (Take a trim off and bounce the car up and down and have a look). We swapped them for much harder durometer and larger bushes on our competition shocks. There is no play left in the rubber now, the shocks now have to do all the work.)