# questions on idler wheel lean



## RobP (Jun 16, 2009)

so I've been trying to BH tune my bow after getting a new cable and string put on recently and I've been having some trouble. I took some time to shoot in the string before I did any tuning. I was getting some great groups out to 60 yards. I walked back tuned with good results and thought I was on the right track to get my BH in tune but my BH are off a little to the right at 40 yards, didn't try any other distance. After a little research here I'm finding out about idler wheel lean. This is all very new to me so I have some questions on the subject. I'm shooting an 08 Diamond Marquis RH. I shoot with an open grip. FOC is 12%

1. Is my BH group indicative of an idler wheel leaning to the left?

2. Looking at the idler wheel from behind the bow the top of the wheel appears to lean a little to the left. Plus measuring ATA on right side of bow is 1/16 greater than ATA on the left side. would any of you consider this to be significant idler wheel lean? 

3. which direction should the twists in my cables be? Does it matter? I don't necessarily trust the bow shop that put them on. 

4. What other affects can a leaning idler wheel have on your shot group?


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## Rhody Hunter (Jul 14, 2008)

It is very important that you know and understand how the bow works with your strings. The information below will explain how your bow works and how strings and cables work. This information is needed before tuning. 


The first step in tuning your string and cables is checking the bow to make sure its hooked up right. Check where the cables cross by the cable guard. There should be a small space between the cable and string on a solo cam and on two cam/hybrid cam should cross in the middle.














After you have checked the bow to make sure its hooked up right its time for cam or idler wheel alinement. Add twists to either side of the split "y" on the idler wheel or cam until it runs true with string. Most bows you will need to add 5 or so twists to get the cam or idler wheel level.You can use a arrow on the side to make sure it runs true to the string. This fixes any cam lean and sets cam or idler wheel for level travel.


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## cornfedkiller (Feb 16, 2008)

RobP said:


> so I've been trying to BH tune my bow after getting a new cable and string put on recently and I've been having some trouble. I took some time to shoot in the string before I did any tuning. I was getting some great groups out to 60 yards. I walked back tuned with good results and thought I was on the right track to get my BH in tune but my BH are off a little to the right at 40 yards, didn't try any other distance. After a little research here I'm finding out about idler wheel lean. This is all very new to me so I have some questions on the subject. I'm shooting an 08 Diamond Marquis RH. I shoot with an open grip. FOC is 12%
> 
> 1. Is my BH group indicative of an idler wheel leaning to the left?
> 
> ...


Very good thread on single cam idler wheel tuning in this thread..It is alot easier to just post a link than try to explain it...

http://www.archerytalk.com/vb/showthread.php?t=1056299

also check out this one (same concept):

http://www.archerytalk.com/vb/showthread.php?t=1118006

To answer your questions:

1) Yes..it is indicative of idler wheel lean, but I cant tell you which way (it actually may not be leaning enough to the left..). I have read opposite ways of fixing bad broadhead flight and paper tuning tears. The thread above says to add twists to the opposite yoke, and I have read that you are supposed to add twists to the same side, and both have proven results, so who knows?? Twist one side, and depending on if it gets better or worse, you know which one to twist. 

2) Most bows will have some lean in them at brace since the cable guard is off to the right. Your string should track straight at full draw, and for this to happen, there has to be left lean at brace (since the cables pulling down on the left side pull less on that side of the limb on the draw than the right side). A quick way to check is just to draw your bow, get set, and then look up the string and see if it is tracking straight down the wheel..

3) Generally, people twist them clockwise while looking at the loop at the end of it (so the bottom of the cable is twisted opposite of the yokes..this keeps them from twisting up on themselves) There is an excellent diagram in the thread here (post #7): 

http://www.archerytalk.com/vb/showthread.php?t=1186928

4) That is pretty much it..

Read through the two tuning threads I posted above..they are both full of a TON of good information from very knowledgeable people...


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## bassman409 (Jul 19, 2006)

RobP, try 1 twist in the left side of the yoke. This may be too much because you are very close to the best. Dont forget that a BH hitting right of FP also can be from a too weak spine on your arrows.


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## RobP (Jun 16, 2009)

thanks guys for the responses. this helps me out a lot. I'm shooting Maxima hunter 350s cut to 27 inches with 100 gr head and blazers. draw weight is right around 60lbs so I don't think it's a spine issue based on Carbon Express's arrow recommendation. I guess I'll have to do some tinkering with it.


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