Making adjustable LCA, start with OEM length?

[proxlamus]

I'm going to be fabricating adjustable front and rear control arms and I've read the stellar FAQ post about LCAs.    

 

 My question is, should the new control arms (front or rear) start at OEM dimensions and the adjustability only increases the length rather than decrease the length?

 

 I ask because I understand the following:

"Rod ends should never be set so that the amount of thread engaged is less than 1.5x the diameter of the end itself. So a 5/8" rod end would need 15/16" threads engaged in order to be considered properly installed. A typical 5/8" rod end has 1 5/8" of threaded shank, so that means that you have 11/16 available thread to adjust with. Subtract the thickness of the jam nut which is 3/8", and that leaves you with not a whole lot of adjustment--5/16" to be exact."

 

 

I was going to initially "split the difference" and with the threads completely collapsed on the rod ends, the LCA will be shorter than OEM length, therefore I could adjust it out to OEM length and beyond for more adjustability.  Would that be incorrect? 

 

[JMortensen]

I would suggest that you consider what you're going to want for camber and work from there. If you want more neg camber than plates will get you, then I'd make the LCAs at least as wide as the stock ones at full compression. With this setup you'd have 5/8" adjustability before you fell afoul of the 1.5x rule. I can't really tell you what plates and stock LCAs will get for max neg camber. I suppose it depends on your ride height. I don't think you can go farther than about 2.5 degrees (would be good to have someone else verify that), so if you are running newer radial slicks or Dot R tires you might need more camber to make them happy. Bias slicks don't need much camber by comparison.

Also keep in mind that there is not a lot of thread engagement in the tie rods, so if you add a bunch of width there you'll need to deal with those too. That's easier now as there are aftermarket ones available.