PSE Cam Lean Tuning

2013_Supra_Max_BK

The objective of cam lean tuning is to get zero cam lean at full draw, this may/usually will, mean that there will be some lean at brace, this is ok.

You will need a drawboard for this as it is impossible to be accurate doing this by drawing the bow and looking in a mirror/getting someone else to look.

If you need to shim lower cam to remove lean at full draw you will need a press capable of fully relaxing your bow. (and a stout heart)

Tip: If you decide to fully relax your bow, you only need to remove string and cables from one end, in the context of this article, the lower cam, I use clothes pegs to clip the string/cables to the riser so as to not allow them to untwist, this will minimise the need to re-synch upon reassembly. When you remove the circlips retaining the cam axles, they will fly across the room and slip into another dimension, be warned and take precautions. Take photo’s of string/cable paths around cam before removing to aid in reassembly. (you know how I discovered the need for this)

Cam description is for right handed shooter looking @ cams from behind.

Make sure of the following:
Your draw length is not set to long so that you draw arm is not in-line with the arrow @ full draw.
Check cam lean @ rest, lay an arrow along the cam and see how parallel the arrow runs with respect to the string.
Do this with both top and bottom cam.
Top cam can be adjusted with the buss cable yoke, two twists can have a profound impact.
Bottom cam cam be adjusted by moving axle shims around. A little goes a long way, PSE use three thicknesses of shims the thinnest being 20 thou (0.5mm) use this first.
Adjust rest centershot so that the arrow is parallel to the notch machined in the riser shelf. It may or may not be directly above the line but make sure it is parallel. Fine tuning later.
Make sure you are not getting rest contact.
move bottom cam shims to produce zero lean on bottom cam at full draw, it will probably look like this /at rest (exaggerated), as you draw, the cables will cause the cam to straighten, becoming vertical at full draw. If the lower cam looks like this \ at full draw, shim the cam further to the right, closer to the cable’s.

More on this later.

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