Cam Rotation and Timing?
 

I was wondering if somebody can please explain to me what cam rotation and timing are? Also what affect these, and what problems can the cause? Will twisting the string a couple times to shorten draw-length affect this? Thanks-Sam

RE: Cam Rotation and Timing?
 

This will depend on the type of cam on the bow. What cam are you shooting?

RE: Cam Rotation and Timing?
 

yeah..more details plaase as it's a pretty lengthy subject..timing/cam rotation, synch, etc.

Cam Rotation and timing are basically the same thing and affect all types of cams

Cam Synch applies to dual cams & to a much lesser extent hybrid cams.

RE: Cam Rotation and Timing?
 

Well I was just wondering in general what can cause this, and what it does. I will be getting a new outback soon so the shop should set it up correctly. I was asking more out of curiosity than specifically about my bow. It seems like twisting the stiring would bring the cam back a little, and then it would almost constantly me like a drawn a very minute amount.

RE: Cam Rotation and Timing?
 

When you get the new outback you might consider replacing the tiger twist string with a low strech custom string. That way once you shoot in the string you wont have to worry about the cam timing.Winnerschoice and Berry strings are both good choices,and if your really interested i know a guy that can hook you up with a set for $50. He can have your string/cable to you in less than a week.

RE: Cam Rotation and Timing?
 

the wheels (or cams) of a two-wheeled compound rotate as you draw the bow. Since their axles are not in the centre, their rotation, in effect, changes the length of the bow. This, combined with the relationship between the large diameter of the string side and the smaller diameter of the cable side of the cam is what gives the compound its familiar peak weight and let-off. There is no need to go into the details, but it is important to understand that if the wheels are not rotating in unison, they are exerting different pressures on the cables, and allowing the limbs to move at different speeds. The end result is complex. Slow motion photography shows that the wheel that starts early does not necessarily reach the end of its stroke first, but at various times may be in the lead, or may be following. This can cause the arrow nock to rise and fall unpredictably during the power stroke, and give a substantial up and down movement at launch. In addition the double impact of the limbs arriving one after the other does nothing to improve accuracy or limit damaging vibration!

Finally, if the wheels are not timed in unison, you are likely to find problems at full-draw, particularly if you shoot off the wall or stops. One wheel will be solidly at the end of its draw, while the other will still be able to move. The end result is likely to be an unstable, rocking movement hardly conducive to a good aim (this is what is meant by the cams 'fighting each other').

RE: Cam Rotation and Timing?
 

So I understand the mathews have holes in there cam and the string is suppose to be between them. If I check this periodically it should be fine? What about twisting the string?

RE: Cam Rotation and Timing?
 

Actually on the Mathews cams when you run a straightedge through the center of those holes, the string should be directly parallel to the straightedge.

Buy yourself a high quality aftermarket string and cable..something like Winners Choice, VaporTrail, Stone Mountain, etc...and likely you will only have to put a twist or two at most in your buss cable after the harness/string settles.

RE: Cam Rotation and Timing?
 

best way to ensure that your string and harnesses are not creeping is to mark the cam in line with the limb check the poundage and record it for future reference
if you ever feel that the poundage and draw length has changed
you can check the poundage.if your draw weight has gone up the string has stretched, if the weight goes down your power harness has stretched
to remedy the problem simply press the bow and twist the string or harness (which ever has stretched) until it is back where it belongs.

this pertains to solo cam bows only

RE: Cam Rotation and Timing?
 

Sure is nice to see that some folks know the difference between timing and synchronization. Too bad most of the magazine writers don't; they almost always use the terms interchangeably!

RE: Cam Rotation and Timing?
 

magazine weiters are normally full of crap and know absolutley nothing about the mechanics of a bow.

RE: Cam Rotation and Timing?
 

So Is twisting the string while it is in timing going to affect it or not? Why would twisting the cable affect the string.

RE: Cam Rotation and Timing?
 

Typically on a single cam after a while on a new cable it will stretch and that will take the cam out of the optimal position. So you need to twist up the cable to shorten it so that the cam is brought back to optimal position.

RE: Cam Rotation and Timing?
 

thenuge15

let me see if I can simplify this
when the power harness stretches it will cause your draw length to become shorter and you will loose poundage and will not get full cam rotation
if your string stretches it will up the poundage and lengthen your draw and will give you more cam rotation.
either way will cause the bow toshoot off because the nocking point and peep will be in a different location.

sure you could move the peep and nocking point and have it tuned with a stretched string or harness but either way it has in effect changed your draw length and changed the rotation of your cam to some degree
which in turn has an effect on the bows preformance.
the best thing to do in such situation is to twist which ever needs to be shortened due to it stretching
this will bring every thing back to its original position

Is any of this making any sence?
I hope so because I dont know how to explain it any better[8D]

RE: Cam Rotation and Timing?
 

Bigpapascout this is making sense, I understood the first time. My question is...I will be buying this bow assuming it timed out correctly. They said they could put a couple twists in the string to shorten my drawlength. Will putting twists in a bow that has proper timing cause the timing to be off from the beginning?

P.S. If both the string and harness stretch than won't they cancel eachother out?

RE: Cam Rotation and Timing?
 

You can twist/untwist both the cable and the string to get the bow both timed and shooting to exact drawlength you prefer (assuming it's close to begin with). This can take a little tinkering with a bow press to get it precise. I wouldn't do this until you've shot 100 shots or more, to settle the string. If you move too far from the normal position, it will affect maximum poundage, because limb prestress is being altered. It can also sometimes make a bow a bit noiser. You are also limited as to how far you can twist or untwist a string, so a custom string may be necessary in some cases.

Try to order the drawlength that comes as close as possible to what you need. Remember, actual drawlength and what is on the bow tag, are generally two different numbers. A mistake here, can be very expensive with a Mathews. Use a measuring arrow to get your drawlength on your current bow, if it fits well.

RE: Cam Rotation and Timing?
 

by twisting up the cable to shorten the length of draw will have little effect but will decreace poundage

if both string and cable stretch equally, this will make the axle to axle length longer, shorten the brace and will decreace poundage.


the best way to get the bow right is to twist the buss cable up to the specified axle to axle length then to twist the string to the spesified draw length.

however it is not uncommon for people to play around with different cable and string lengths to where the bow suits them.

it is kind of hard to get a solo cam bow out of timing considering it only has one cam. what you have to be morer concerned with on solo cams is cam rotation, allways better a little too much than not enough IMO
that is of course me speaking as a speed freak[8D]

RE: Cam Rotation and Timing?
 

So when a bow is shot with the cam pulled back some because its under rotated it will not damage the bow, the cam will just stop right there and not want to go further?

RE: Cam Rotation and Timing?
 

No
It will not damage the bow.