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Sway Bar arm attachment methods (why splines?)


New Member
I was just thinking about sway bar attachment methods to the arms. Typically systems use splines (if the bar isn't one solid piece including arms.

I've been reading up quite a bit on sway bars and it seems like a lot of people are saying that the splines strip out, and occasionally people even weld the arm to the bar to finish out a race.

Why aren't other attachment methods popular. You could do a key and a keyway method (like smaller gokarts use to keep the disc brake and sprocket on the axle) as seen here: goo.gl/1bn1cl

You could also do a hub style end. The stub with hub could be welded into a hollow tube, or onto a solid tube, similar to a CV flange seen here: goo.gl/ClFcWT

I'm not sure if I'm missing something, or if it's just a weight issue. but it seems to me that some grade 8 bolts or two-three keyway slots could work better than splines.

Splines give you multiple angles to attach the arms, but since the attachment points are only on both sides, as long as you have both sides symmetrical, you'd be fine.



Well-Known Member
Sway bars like torsion bars are spring steel, should not be welded as it messes up heat treat, splines are mostly so one bar can be used in many ways, there is no standard mount or connection method so splines accommodate many options


Well-Known Member
Short of making the arm and bar one piece, splines are the strongest way to connect two independent pieces together.

If people are stripping aluminum arms they should switch to steel (4130?), it has higher tensile strength and is better in shear. Or make the arm wider at the splines...

Shear strength - Wikipedia, the free encyclopedia


Bear on a Unicycle
I knoe sandy Cone built s sway bar on the back of a truck he helped on .. It doubled as spare axles .. Along with spare hubs.. Pretty cool design

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Well-Known Member
Splines on a sway bar are not needed for clocking the arms because the arms are parallel and the bar is floating in it's bushings.

Splines are vastly stronger for transmitting torque compared to keys and keyways.