Kitabel, with all due respect.kitabel wrote: ↑Thu Aug 18, 2022 2:43 am The brake arm can act in tension from below the axle, or in compression from above the axle. Since the rear axle is fixed (no suspension travel), even allowing the caliper or bracket to rotate until it contacts the frame. The length and position of the link do not matter as long as the caliper can be bled. The link for a swing arm should be floated at both ends to transfer braking load back into the chassis, rather than loading the suspension.
If in compression, the attachment must be stiff enough to prevent bending; in tension even a 5/16" rod is enough.
Any lateral misalignment (link not parallel to the wheelbase) should be cured with shims (rather than a Heim joint).
His rear brake anchor tab is on lower tube of rigid frame, hence without welding, he needs a tension brake stay.
On most Harleys, but especially on a rigid frame, a floating rear brake support with parallel link does absolutely nothing, except create unnecessary work and more things to go wrong.
It is my humble opinion that, only those with a death wish would use a 5/16" tension rod on a rear brake, floating or not.
I don't doubt that a 5/16" rod material could be found that, on paper, exceeds the tension force induced by the caliper. But when you cut a thread on it, weld some eyes to its ends, or whatever to make it actually work as a brake stay, all your calculations go out the window.
No production motorcycle uses anything close to a 5/16" rod for a brake stay, they all use similar to above Willwood pic, its called added safety factor.
Sure, the brave and knowledgeable could thin it down a bit, at their own risk...
The poster Nanonevol appears to be an ordinary guy, building a motorcycle, to me, what you suggest Kitabel, is downright dangerous and potentially lethal.
Nifty