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Usually round tubings are the choice for fabricating the LCAs. But I'm wondering why we can't use the square tubings. Looks like the square tubings can save the trouble of tube notching, which I've been trying to avoid... The only drawback i can think of is the adapter on the end of tube where it connects with rod ends. It will have to be square and you will have to mill it. But that's not too much trouble comparing to the part on round tube, which will be done on a lathe.

So why we don't see many LCAs made out of square tubings? Is it because of the strength? To acheive equal strength you will have to upsize the dimension and it ends up being too heavery, or what?

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Peace, Ron

Either way is fine. Mostly it has to do with the dims of the parts on the ends. but for the same material square is stiffer and heavier than the same size round. No special milling setup is required for either one.

Some mistakes are using too small a tube (bending), too thin of a wall thickness (buckling), LBJ too far from the coilover (bending), or two hard/high carbon material for the tube combined with size/wall (cracking).

Ideally, when overloaded/in an accident, the arm will just bend without damaging the frame and not break off the car with the wheel.

I'm using "1 inch" black pipe (like from home depot) for my rear lcas with 1.5 inch pipe for the lcap bushing shells. You find most aftermarket control arms are heavier than the original arms.

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

I would hearty recommend the Kinetic setup. Easy to build, flexible build options, super strong, great price. Mine have stood up to a lot of abuse.

Graham