Shackle Angle Tech

This will require some discussion on the optimal flat-spring shackle angle. I say 50 ~ 60 degrees. Steeper angles should make for a slightly harder ride. Ride height shackle angle will depend on ride height spring arch.

Your full droop shackle angle really shouldn't go beyond 90* (straight up and down). To determine a good shackle length, measure your springs eye to eye (straight line, don't follow the arch), and if this length is less than your spring mount to shackle hanger seperation, try a longer shackle.



H = Sin(A) * L

Or, where SpL = spring length (dead flat), and MH = the distance between spring mount and shackle hanger:

MH = SpL - Sin(A) * ShL

For example, when using 47" waggy springs, 5" shackles, and a 60* shackle angle (with springs flat), the distance between spring mount and shackle hanger should be:

MH = 47 - Sin(A) * 5
MH = 47 - .87 * 5
42.65" between mount and shackle hanger.

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