Modules affecting draw length

whoami-72

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How does changing modules affect draw length? I was watching inside out precision. See link below. He mentioned that changing letoff by 10% on a mathews could affect your draw length by 1/2". Has anyone tested the same with changing draw weight? Would going from 70 to 75lb modules shorten the draw length?

 

Billy Goat

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Mathews changes the letoff percentage by stopping the cam rotation sooner. It seems to usually be 1/8" difference going from a 85% mod to an 80 on the SW cams, and about the same on the C3X cams on the TRX bows going from 80%- 75%. That's without making an adjustments. I have 75's on my 40 but twisted the string up a little, think I took a twist out of the cables and my letoff is at 67% now. Gets me close to the same holding weight across the board on all my bows.


I haven't seen changing mods of the same draw length effect it anywhere like 1/2".
 
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whoami-72

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Mathews changes the letoff percentage by stopping the cam rotation sooner. It seems to usually be 1/8" difference going from a 85% mod to an 80 on the SW cams, and about the same on the C3X cams on the TRX bows going from 80%- 75%. That's without making an adjustments. I have 75's on my 40 but twisted the string up a little, think I took a twist out of the cables and my letoff is at 67% now. Gets me close to the same holding weight across the board on all my bows.


I haven't seen changing mods of the same draw length effect it anywhere like 1/2".
Thanks, I ended up finding out that it was specific to the Traverse. Apparently Mathews knew about it and intended it that way. Have you noticed anything by changing draw weights?
 

Billy Goat

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Thanks, I ended up finding out that it was specific to the Traverse. Apparently Mathews knew about it and intended it that way. Have you noticed anything by changing draw weights?

I have seen the timing slightly change on SW cams by changing the mod poundage. Haven't seen a difference in draw length when staying with the same length and letoff. At least not too noticeable, I'm sure there's probably 1/32 or so if the timing is slightly off.
 

TheBootBowhunting

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I have VXR 28s set up at 70 and 75 lb. The 70 pulls 73, the 75 pulls right at 80, 79.7. The DL is nearly dead on between them. I had 70#/85% mods on the one that now has 75#/85% and didnt have to mess with the timing after I swapped the mods out.

Last year when I switched from 85 to 80% letoff for Colorado, it measured ~1/4" shorter. Glad CO did away with letoff reqs.
 
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BBob

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V3-31. ~1/16" ish shorter draw with 75lb 80% mods and 1/2 twist in a buss for timing coming from 70lb 85%. I'm sure some swaps there will be no timing change and some will with slight machining variances between the mods
 
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