Agreed with everything stated..
i do have a goofy one thought, i super tuned my diamond nitrous, but to get broadheads and field points to fly together i have to have a tiny high tear through paper..

 

I've read that persistent high-tears on single cam bows may be due to an overly stiff spine. I've not yet had any problem with arrow spine being too stiff. However, I have run into problems with spine being too weak.

Although I'm an avid reader/researcher, I've learned much of this the hard way - shooting hours and hours, day after day at the range, in my garage, etc until my arms can't take it any more.

Another common misconception is to use side-to-side arrow rest adjustments too early before you get the cam lean correct. You can get decent arrow flight by doing that, but I got better results by starting with eveything in line, then getting cam lean right, then making micro adjustments to the rest only during broadhead tuning.

Edit: I used the term "cam lean," but it is more correctly "idler wheel lean" as the yolk attaches on either side of the idler wheel. I'm not sure how I came to call it cam lean.

Ray

 

First, great write up. Thanks for taking the time to share that

But that just looks like run of the mill tuning to me

 

Posting to bookmark this. I may be adding an inexpensive single cam bow to my stable.

 

posting to bookmark this. I may be adding an inexpensive single cam bow to my stable.

+ 1

 

Nice job, but I do have one question. Are you talking about Cam lean or Idler lean. The cam on a Mathews bow should always be very close to parallel with the string. The Idler wheel on the other hand should always be close to straight up and down at full draw, and at rest have some lean.

 

Yes, it is idler wheel lean. I've always heard it called cam lean, but I should have called it idler wheel lean. The yolk attaches on either side of the idler wheel, so that is what we are adjusting.

I have never seen a tuning guide that start with idler wheel lean adjustment to get bullet holes. They usually start with adjusting your arrow rest.

Also, if you get it to shoot bullet holes through paper with a bare shaft, you can put on a mechanical or a lower profile fixed head and it will probably group field points and broadheads pretty well - at least under 50 yards.

Ray

 

Good write up / info.

 

This might be common knowledge but I didnt know any of it so I appreciate the write up. Thanks. I will be printing this and adding to my Archery 3 ring binder.

 

Great post Ray. I see way too many people start tweaking their rest before making sure the bow is spec'd out and the string is tracking true.String track is the cause of 90% of the tuning problems, imo.

 

Hi Krieger.

Yes, and things get pretty strange when you try to patch an idler wheel lean problem by shifting the rest.

I often hear of guys who say they just can't get a bullet hole and I'm pretty sure it is due to either 1) idler wheel lean or 2) spine problem. You rarely hear about how to adjust your idler wheel properly.

Ray

 

bump

 

I am just starting to play around with tuning my mathews bow and my wife's mathews bow. I was just wondering about one measurement you gave in #4 (11/16" from riser to center of arrow on Mathews). In the mathews manual it says to start at 13/16" from the riser to center of the arrow.

Actually, I always align the string, cam, wheel and arrow so they are all in allignment. I do it by eyballing down those various points. It ends up being 11/16" on both of my current type of bows (Mathews LX and Mathews Conquest). If it came out at 13/16", then that is where I would start. Remember, this is just the starting point, but you will use it to get your idler wheel lean correct and your rest height correct. I don't adjust the rest side to side until after I get bullet holes with bare shaft, then start doing broadhead tuning. And if you get bullet holes with bare shaft, when you go to broadhead tuning, you will not have to make much rest adjustment at all - usually less than a 32nd of an inch in any one direction. In your case, I would start with what the manufacturer recommends for you to start at 13/16" unless you want to eyeball it like I do.

Also, I have read several places about setting the nock up to 1/2" above the 90 degree point to start out. Why do you do this and not set it perpendicular initially?

Single cam bows have vertical string travel due to the cam, but this only happens from below where the cam is. Dual cam bows both travel so the nock does not move up and down during the release, so I would expect that you start the nock point level for dual cam bows. It does not hurt to start where they recommend because you are going to change it after shooting your bow and only to improve the flight of your arrow and broadheads.

Have fun! It is fun and rewarding to do your own equipment and to be self-sufficient. And if you have any questions, I'm always happy to help.

Ray

 

Nice write-up

However, If i set my rest at 11/16ths on my SBXt, and idler wheel tuned, i bet the string would fall off before I got a bullethole.

 

SBXT must be one of the 13/16" models. Like I said, I prefer to eyeball it so the string, cam, idler wheel, and nocked arrow are all in line. That should work in any case. Any specific measurement is likely to be right for some models of bows.

Ray

 

Thanks

 

My new LX string and cable arrived today from H&M. I'm gonna go put them on right now!

Ray

 

Interesting read. I shoot custom strings on most of my Mathews bows and have my string guy make a floating yoke. I really haven't had any issues with idler lean, though I do typically look for it.

I have had great results just "bench tuning", starting with the d loop at dead level (and thru the center of the berger button hole) and centershot set with a guage......9 times out of ten I can just go out and walk back tune right off the bat, generally with broadheads. I have never worried about my broadheads and FP's hitting the same place. But by walk back tuning the fixed blade broadhead first, the FP's and expandables generally follow and shoot in the same hole all the way out.

I've had great luck going with a fairly stiff arrow. In fact, I have yet to have a problem with "too stiff" since I started shooting carbon about 10 years ago. I have however gotten burned "too weak", especially with Gold Tip arrows. Great arrows, but their spine charts were always on the weak side IMO.

Gotta love the single cams, though....Even a rookie can get them shooting good, and if you spend the time Ray does, you can have a true tack driver.

Thanks for a good thread.

 

Interesting read. I shoot custom strings on most of my Mathews bows and have my string guy make a floating yoke. I really haven't had any issues with idler lean, though I do typically look for it.

I've seen these floating yolk on other bows and wondered if they would be better or worse. 1) you don't have to adjust lean, but 2) you can't adjust it if you need to. I would expect that, as long as your limbs are consistent in strength and not twisted, the floating yolk would be better.

I have had great results just "bench tuning", starting with the d loop at dead level (and thru the center of the berger button hole) and centershot set with a guage......9 times out of ten I can just go out and walk back tune right off the bat, generally with broadheads.

My experience is consistent with yours except that I invest the time to get bullet holes through paper with a bare shaft to ensure I'm super close before I start shooting broadheads. If I get it shooting bullet holes with bare shafts at my shop, it is usually good enough to shoot broadheads and fielld points together for most hunting situations. However, I like all my bows to be tack drivers (like you said), so I do the minior tuning of the arrow rest to get Muzzy's and field points together out to 100 yards.

I started on this quest when my buddy bought a brand new Mathews Switchback (four years ago) which was set-up by a pro hunter who has his own shop. It would not shoot broadheads with field points no matter how we adjusted the arrow rest. I suspected the broadhead, the arrows, (and tried all variety of alternatives), but nothing fixed that problem. He took it back to the pro shop-owner twice, but he could not get it done correctly. Finally, I read about setting idler wheel lean and tried it. Adding twists to the right yolk reduced the left tear, so I kept doing it until I got bullet holes. Then the problem was fixed and I was able to make his bow a tack driver too.

I've had great luck going with a fairly stiff arrow. In fact, I have yet to have a problem with "too stiff" since I started shooting carbon about 10 years ago. I have however gotten burned "too weak", especially with Gold Tip arrows. Great arrows, but their spine charts were always on the weak side IMO.

Amen! My experience is exactly the same! I just bought a dozen Victory 350s that were correct for my bow by the spine chart, but there is no chance they will fly right out of my bow. I really need the 300s. I've always been able to shoot the stiffest arrows made with no problem.

Gotta love the single cams, though....Even a rookie can get them shooting good, and if you spend the time Ray does, you can have a true tack driver.

Great point! They really are simple and easy. While I was trying to figure them out, I kept telling myself, "this isn't rocket science, it is just a bow and arrow."

So, Manybows, have you tuned dual cam or cam and a half bows? How are they different than single cam?

Ray

 

Good post Ray! :thumbs_up

Lots of Mathew shooters look at other things besides the idler when they can't get consistent, good arrow flight, and it can cause problems if it's not set right.

You mentioned cam timing, but you forgot to mention Mathews cams HAVE timing holes, and yes, a single cam bow CAN be out of tune.

If you fiddle with it long enough, you will find a sweet spot in your cam rotation, and if you have a quality aftermarket string, it most likely will not move.

My cams work best on my Drenalin slightly under-rotated.


Very helpful post Ray!

 

...a single cam bow CAN be out of tune...if you fiddle with it long enough, you will find a sweet spot in your cam rotation...My cams work best on my Drenalin slightly under-rotated.

Wow! I have not tried setting the cam forward or backward from recommended timing. I always set the cam timing as part of the "get the bow in spec" part and assumed it would behave best where it was designed to.

That is interesting your Drenalin works best slightly under rotated.

Ray

 

Last night, I put my new H&M string on my LX. I set it to spec, then set the rest where I explained above, then I never moved it. I only adjusted idler wheel lean (via twisting the yolks) and nocking point (by removing and reattaching the D-loop. Now it shoots perfect bullet holes. Tomorrow, I'll head to the range and do broadhead tuning.

I always set the initial idler-wheel-lean so when I place an arrow on the shelf side of the idler wheel, the arrow is perfectly parallel to the string. That is usually pretty close to right. I had to add a few twists to the left (the side without the shelf).

Ray

 

How do you determine idler lean? Just by looking at the idler while the bow is undrawn, while you draw it, on a draw board, or while someone else draws it?

 

The main point of this thread is it can only be set correctly by achieving bullet holes through paper with a bare shaft.

Cam timing and ATA can be set properly by static setup and measurements.

You can eyeball the setup for initial rest windage (arrow, string, cam, and idler wheel all in alignment) and elevation (arrow even with the burger button).

You can set the initial idler wheel lean setting by placing a straight edge (like an arrow) against the shelf side of your idler wheel, then seeing how well it parallels the string. I look at the point near the nocking point. I start with the arrow pretty much parallel to the string, then do dynamic adjustments from there.

But then comes the shooting a bare shaft through paper and twisting yolk to remove nock-right or nock-left tears. You can raise or lower the nocking point to remove nock-high or nock-low tears.

Ray

 

On my Marquis I get the bow in spec, I measure axle to axle on both sides of the bow and then look at the idler wheel and take the strings/cables away form the roller guard. When there is no pressure from the rollers the idler wheel will be dead straight and when on the rollers it will become straight at full draw. Seems to work for me.

Totally agree with No.7

Saves you from running out of adjusment within the pin guard.

 

Good post but i'm not sure about the berger button hole.I was told to center the bottom of the arrow shaft with the middle of the holes and thats how i've alwasys done it and seems to work great for me.I've also seen shops that lined up the bottom of the shaft with the bottom of the holes and i guess that would work to,but i perfere the other way.All rests are different.....and not all rests will allow for vane clearence.A few rests on the market will allow the adjustment for raising the launcher.....not launcher arm.Some rests that only allow you to adjust the launcher "arm" up and down doesn't mean you'll be able to have total vane clearence.....because your only moving the arm.....not the launhcer.2 shops that i know of say to set nock 1/8 high....another says nock level....for single cam.....i use the 1/8.Not sure if 1/8 or level makes that much difference.....but 1/8 seems to work good for me.

 

you're reading too much into it. Bows are different and some will tune better one way while others another way. Unless you know specifically that the bow in your hand will tune better with the bottom of the shaft lined up with the center of the berger hole, then just centering it is a good starting point. And to be quite honest, in my experience unless the bow is just finicky and has some funky nock travel, you will be able to tune it either way.

Same thing with the nock height level. 1/8 or level as a starting point is just that, a starting point and some bows will tune differently. Not all single cams are created equal

 

Nice write up.

 

Wasn't reading to much into it......i said good post.....and your right...it's just a starting point and each will tune different in the end.What i said wasn't ment to be cast in stone.....just a post.But thanks for being concerened and enliteing me on what i read.:darkbeer:

 

sounds like this would work well and be easily done with the cable adjusters that spot-hogg made. but i don't see them on their website anymore.

 

The entire thing is not too bad if you have a good bow press. I press my bow quite a few times when setting it up.

I consider a bow press essential equipment if you have a compound bow. That is why I was happy there are now affordable ones that are pretty good. I use an Omni Press that cost about $150 shipped and it does the job well.

I don't consider the portable bowpresses suitable for serious bow work. Sure they work, but they just are not quick enough to allow you to do all the minor adjustments you should do to get it right. I have a BowMaster, but only keep it in my gear bag in case I should ever have an emergency while hunting such as needing to reinstall my peep.

Ray

 

Just to show that these initial numbers don't stay the same after you start dynamic tuning, I measured how they came out after getting my LX to shoot bullet holes last night.

Distance from riser shelf to center of arrow: 12/16" (not 11/16" or 13/16" which are two common recommended starting points, my Conquest came out right at 11/16"). This is where the string lined up with the cam, idler wheel, and arrow on my LX.

Distance nock is above level: 1/8" (and that was critical to get the bullet holes)

Distance of straight edge from string nocking point when placed on riser side of idler wheel: 3/16"

Notice how much the idler was adjusted to get it right. I started with 1/8" which had the straight edge nearly parallel with my string, then added quite a few twists to get the 3/16" distance.

I bet not all LX bows are the same. They may all be similar, but there are going to be slight differences in materials and configurations that may or may not affect the setup that gives optimal performance.

Yes, I don't think it is critical to have your arrow even with the berger button, but it is pretty close to the center of the string and as good a starting place as any. It may affect where your sight ends up which may be too high or too low depending on your anchor point.

Ray

 

Tuning

I have been reading this thread with great interest. I have a drenalin LD that I am struggling to tune. Dren LD @ 59 # , 28.5 DL, Trophy taker shaky hunter{ Fletch does not contact arrowrest, did a lipstick test to make sure} gold tip 75/95.The 55/75 was worse. Helical 4 " fletch. Persistant stright left tear.The only way I can get it to bullet hole is to move the rest way too close to the riser where I just barely have clearence and reach way too deep into the grip. Grip is a hicks low wrist. Factory grip did not work. I have a torqueless wooden grip coming. The bow does have a string stop on it. Looking at the Idler wheel it appears to be ever so slightly tilted to the right. from what i was reading in the previous stuff, a left tear calls for twisting up the right yoke which will further increase the cam lean. I suppose untwisting the left yoke would strighten the idler and give the same effect as twisting the right side. Any suggestions on the DLD would be appreciated.
wayles

 

How do you adjust cam timing?
What are your steps?

 

I've found that my best shooting Mathews rigs always ended up being under rotated.
Starting with 1/8" above square for nock height is always good, but sometimes it goes a little higher to get the bow to hold (aim) better.
This is a great thread.
Adjusting cam lean helps settle out the little tail whip issues. Its all for naught if you don't have a good, consistent grip though.
I wrote down the major points of your tuning guide, even though I do them normally. Its good to see it all on a list so when you can get them all systematically when you change out a string (like I did last night) and not forget anything. Great thread.