Typical lateral movement of triangulated four link

[Rhino]

I realize that this question is rather open ended, although I'm wondering how much lateral movement I should expect from a triangulated 4 link. Due to packing restrictions, I'd like to try running without a panhard bar. I wouldn't mind running a bar, although I think it will be getting tight with a stock tank, coil overs, and exhaust.
The car is a '68 Camaro, and will be mini-tubed. I'll be running coil overs and canting them in toward the top to also help with lateral stability. It will see mostly (75%) street driving, although will be driven hard on the autocross the remaining 25%.

The reason I ask about lateral movement is that I need to determine rear end width and also insure the wheels I have picked out will clear.
I've always planned on having approximately 1" space between my wheel and tubs. By my calculation, I should have roughly 1.2" clearance on either side of the wheel. (10.5" wheel with over all width of 11.5", .25" brake rotor thickness with a 14" total wheel tub diameter)



Is the 1" cushion enough? Is it too conservative? Am I crazy for not wanting to run a panhard bar?

[claytonisbob]

It depends on how tight/new your components are, but I would bet 1" cushion would be plenty.

[GMracer]

All depends on how much triangulation, what kind of bar ends. Way to many variables, but 1" cushion should be plenty for a well setup tri4

[Rhino]

I'm glad that it should be enough.
With this in mind, Is there any resource I can utilize to determine potential deflection given a specific G load and geometry? If it turns out I can run an 11, rather than 10.5, I would be open to doing so.

I realize more triangulation=less deflection, but haven't really decided on a set up yet.
My plan has been to use a quality joint. Currie johnny joints or some of the nicer 3 piece QA1's are the current choices.

[claytonisbob]

Technically a triangle shouldn't deflect at all (assuming everything is perfectly strong and tight)... joint slop and component bend is what creates the deflection. More triangulation will help compensate for joint slop. But I don't think there is a formula for it.

I'm running a 315 tire on 11" wheels under stock '69 Chevelle rear fenders. I think I had less then 13" of space at the lip and everything clears pretty well. With 14" wells Id imagine you'd be fine with an 11" wheel assuming you get the right BS.

[silver69camaro]

For a reference, we find our tri 4-bar moves laterally about 1/4" in hard cornering. We can allow 1/2" tire-to-fender without issues.

[Rhino]

Thanks Matt. I appreciate your input. That at least puts me in the ballpark. I should be able to run an 11 and still have a fair amount of clearance.

Claytonisbob... Are you running the stock 4 link in your Chevelle, or a custom setup?

[claytonisbob]

Stock 4 link, Edelbrock uppers and some lowers I made from aluminum trailing arm stock and poly bushing rod ends on one side and JJoint rod ends on the other side. Bilstein shocks, 175lb springs.