Modules affecting draw length

whoami-72

Lil-Rokslider
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Sep 13, 2021
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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?

 
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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

Lil-Rokslider
Joined
Sep 13, 2021
Messages
230
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?
 
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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.
 
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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

WKR
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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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