how much effect does draw weight have on draw length?

[sambow]

I have two merlin bows, when I compare their draw length with the specifications for the cams and modules fitted, one is 0.5 inches longer, the other is 0.8 inches longer. On both the power and control cables are not quite inbetween the tuning guidelines. I have measured all three cables on each and they are to spec.

Both bows are set at their lightest setting with the limbs fully wound out.

The question I have is if a compound bow is wound fully out, is there an appreciable difference in draw length compared to fully in? (I can't test it because I could never draw them fully wound in!)

[pwiles1968]

As Far as I am aware Poundage has no effect on Draw length, if you are worried about the bow you should PM Ben - Merlin Archery, he may even post on here if he sees it.

[sambow]

I might talk to Ben. My Supernova with Omega 2 and OM5 Modules is coming in at 29.8" draw length wheras I need 29.25". To get any smaller with cams and modules will require a new cam as well as module, which I was on the verge of ordering, then I realised its quite a lot longer than spec (spec says 29"), so I was just investigating if there was a cheaper way, to get down to what I need.

I found out something interesting while tuning the cams on my other bow. One twist of the control cable affects the draw length by between 6 & 10 mm which I found really hard to believe. I think I will be playing with my super nova tonight.

[geoffretired]

I don't know the answer but I may know a way to find out.
With the bow set as at present, measure the axle to axle length very carefully. Also note the rotation of the cams in relation to the bow string.
Then wind in the limbs fully and measure the axle to axle again and note the rotation of the cams.
If there are changes, such as the cams have rotated, you will have your answer.

[sambow]

I like that, its easy to do also!

Originally Posted by geoffretired

I don't know the answer but I may know a way to find out.
With the bow set as at present, measure the axle to axle length very carefully. Also note the rotation of the cams in relation to the bow string.
Then wind in the limbs fully and measure the axle to axle again and note the rotation of the cams.
If there are changes, such as the cams have rotated, you will have your answer.

[pyroarch57]

Originally Posted by geoffretired

I don't know the answer but I may know a way to find out.
With the bow set as at present, measure the axle to axle length very carefully. Also note the rotation of the cams in relation to the bow string.
Then wind in the limbs fully and measure the axle to axle again and note the rotation of the cams.
If there are changes, such as the cams have rotated, you will have your answer.

Or a quicker way, check the brace height.

[geoffretired]

Pyroarch, don't leave me in suspense, how does that work?

[pyroarch57]

Originally Posted by geoffretired

Pyroarch, don't leave me in suspense, how does that work?

The same as your way. Any change in limb/cam position (if any) will show in brace height.

[geoffretired]

I see what you mean.Thanks for that.
Either way, I will be interested to know the results.
From sambow's other post, and the extra twist in the cable making so much difference, I would think that the slightest error in cable length could be the reason for his long draw length.

[pyroarch57]

Originally Posted by geoffretired

I see what you mean.Thanks for that.
Either way, I will be interested to know the results.
From sambow's other post, and the extra twist in the cable making so much difference, I would think that the slightest error in cable length could be the reason for his long draw length.

Yes me too. I`m struggling to see how one twist on the control cable can change drawlength by 6-10mm though.