# All you Pearson R2B2 tuning guys.......HELP!



## BullElkKiller (Mar 13, 2007)

What is your draw length? How much weight do you have on the string? I have the Z-34 with R2B2 cams and it shoots the speeds it should. I lost some speed when I replaced my strings/cables. However once I added the speed nocks my speed came back. I am shooting a 392 grain arrow 29"/71.5 lbs., 15 grains on the string at like 312 fps.


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## Bert Colwell (Jun 25, 2005)

Thanks for pointing that out. I am shooting a 29" draw. Nothing on the string but a meta peep and small D loop.


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## BullElkKiller (Mar 13, 2007)

You should be getting close to 300 fps. Have you checked cam timing? Does your string have speed nocks on top and bottom? my bow was alot slower without the speed nocks in place. Check your specs: axle to axle, brace height, etc.


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## SonnyThomas (Sep 10, 2006)

Try this. It's supposed to be in the ballpark. Start with IBO; 70#, 30" draw and 350 gr arrow.

2 fps / 1 # of Draw Weight
10 fps / 1" of Draw Length
1 fps / 3 grains of arrow weight
1 fps / 3 grains of weight on the string


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## Bert Colwell (Jun 25, 2005)

BullElkKiller said:


> You should be getting close to 300 fps. Have you checked cam timing? Does your string have speed nocks on top and bottom? my bow was alot slower without the speed nocks in place. Check your specs: axle to axle, brace height, etc.


The axle to axle is 1/4" long, and the brace is 1/8" short. Should I twist each control cable equally, until the axle to axle is correct? The bow already peaks at 75# from the factory.


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## Bert Colwell (Jun 25, 2005)

ttt


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## MitchFolsom (Jan 11, 2006)

Sound to me that you may have a timing issue. With these cams you can lose a ton of speed on out of time cams. IMO forget the ATA, and brace height right now. Worry about the timing. 

Do you have heavy imbs on there? If it's a 70# bow, the cables are already pretty well twisted up it seems. I just think it's a timing issue. You'll need a drawboard to make sure.

Are there speed nocks on the string? These can make some difference.


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## SonnyThomas (Sep 10, 2006)

Are you measuring correctly? Should be outside of one axle to inside of the other axle. Ata 1/4" long and bow peaking at 75 pounds is way out of specs. How long have you had the bow? If not long and even if long I'd take it back and have it made right. At 75 pounds with limbs maxed out and bolts turned out to get down to 63 pounds might be pushing the limit of safety. Herein may be some of your problem.


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## MitchFolsom (Jan 11, 2006)

SonnyThomas said:


> Are you measuring correctly? Should be outside of one axle to inside of the other axle. Ata 1/4" long and bow peaking at 75 pounds is way out of specs. How long have you had the bow? If not long and even if long I'd take it back and have it made right. At 75 pounds with limbs maxed out and bolts turned out to get down to 63 pounds might be pushing the limit of safety. Herein may be some of your problem.


I know at one time there was a problem with some limb pockets that were causing the bows the peak out like crazy. I wouldn't think this would be it. The limbs were also running heavy one some sets. My 60# will get up to 66#, a friends will get to 68#. So IMO it's no that high of poundage. The limbs can take it, there Barnsdale.

On this bow the BH is important, but nothing is as important as cam timing. Timing, timing, timing is what makes the speed on this bow!


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## Bert Colwell (Jun 25, 2005)

This bow is only a few days old, and it one of the later releases. The limb pockets and strings are all current. I have already called Pearson, but will call them again tomorrow. I just can't find anything that tells me how to properly time the cams to ensure their rotation optimized. If any one can post or PM an explanation of the procedure, I would really appreciate it.


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## Bert Colwell (Jun 25, 2005)

ttt


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## JuniorsOutdoor (Apr 11, 2008)

Bert Colwell said:


> This bow is only a few days old, and it one of the later releases. The limb pockets and strings are all current. I have already called Pearson, but will call them again tomorrow. I just can't find anything that tells me how to properly time the cams to ensure their rotation optimized. If any one can post or PM an explanation of the procedure, I would really appreciate it.


There is a video on youtube about timing your r2b2 cams. It is very helpful. Search for "r2b2 timing" in the Youtube search bar.


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## Petapal (Nov 29, 2007)

*R2b2*

The You Tube vid is good but they don't give you a specific measurement to work with when timing.I haven't found anyone who could give it to me.What I did was to make sure my cables and string were to spec and then time the bow by making the measurements equal. Mine shoots awesome now. If you need some more help get in contact with Jim Rumps at Select Archery.He's here on AT or you can Google Select Archery and then E-mail him.Pearson is his Bow of choice so he's pretty knollageable about them.I don't have a clue what i'm talkin about so good luck LOL.


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## JuniorsOutdoor (Apr 11, 2008)

Petapal said:


> The You Tube vid is good but they don't give you a specific measurement to work with when timing.I haven't found anyone who could give it to me.What I did was to make sure my cables and string were to spec and then time the bow by making the measurements equal. Mine shoots awesome now. If you need some more help get in contact with Jim Rumps at Select Archery.He's here on AT or you can Google Select Archery and then E-mail him.Pearson is his Bow of choice so he's pretty knollageable about them.I don't have a clue what i'm talkin about so good luck LOL.


No they don't give you a specific measurement, but I don't know that there is one, is there? There might be a specific measurement, but I don't know what that would be or what you could measure aside from maybe the cable to post measurement shown in the video. I believe that is completely dependent on where each person sets their draw stop though. The key to timing and I believe what the video is trying to show is how to make sure each cam is in sync with the other.


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## Bert Colwell (Jun 25, 2005)

Thanks for all your suggestions and help. I am really just trying to learn all I can about these cams. My bow is not performing even close to what everyone says it should do. I have a new set of strings coming from Winner's Choice, so I though I would check everything when I installed them. Since the bow is already peaking out at 75 pounds, I have been reluctant to twist the cables up any more. I feel like the draw is running short, so I suspect the string is is too short.


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## MitchFolsom (Jan 11, 2006)

What I do for getting the cams in time is to:
1. Put it on a drawboard. Crank the bow back, with the drawstop in the shortest setting. Crank it back untill the stop hits the limb. Not buried into the limb, but hitting it like youwere going to shoot it.

2. While the bow is still at full draw, take a tape measure and measure the distance between the outer cable peg and the inner cable. Both the top and bottom cam should measure the same. If they aren't, twist/untwist the cablr to bring the cam back into speck. If I have one that is a shorter measurement than the other, I like to adjust that cam.
To my knowledge, there is not a written measurement on this. Jim from Select archery talked about this very same issue once before.

3. If you have a scale that will check letoff, now is a good time to do that. In small amounts move the stop out until you have reached your max letoff. It maybe 77%, or 80%. Some bows will only get so much, it's really luck of the draw.

4. Now that the bows cams are timed, anything you do needs to be done in eqaul twist/untwist in the cable. And now you can work on your ATA, and braceheight.

Note this. Installation of a drop away rest that attaches to the down cable can throw the cam timing off on the bottom cam. The timing needs to be done with the drop away installed on the bow for best results.

Hope this helps. Send me a PM if you have anymore questions.


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## Bert Colwell (Jun 25, 2005)

Thanks for all the input guys!


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## Petapal (Nov 29, 2007)

*R2b2*



Bert Colwell said:


> Thanks for all the input guys!


You're getting some great info here but;
without a specific measurement between the post and string you can time all day and not get max performance out of your bow.
FIRST YOU NEED TO GET YOUR CABLES AND STRING TO SPEC THEN TIME.
GOOD LUCK


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## JuniorsOutdoor (Apr 11, 2008)

Petapal said:


> You're getting some great info here but;
> without a specific measurement between the post and string you can time all day and not get max performance out of your bow.
> FIRST YOU NEED TO GET YOUR CABLES AND STRING TO SPEC THEN TIME.
> GOOD LUCK


Again, correct me if I'm wrong, but I don't think there is a specific measurement. I think the only thing that really matters is that the measurements on both sides are equal. I would think that because of the different size cams and different draw lengths that each draw length would have a different cable to post measurement. Any variance in string length, axle to axle length, and brace height would change that measurement as well. If there is a specific measurement I'd love to know, so if I'm wrong please help me out as well. I agree to get everything to spec and then time though.


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## MitchFolsom (Jan 11, 2006)

JohnBSox said:


> Again, correct me if I'm wrong, but I don't think there is a specific measurement. I think the only thing that really matters is that the measurements on both sides are equal. I would think that because of the different size cams and different draw lengths that each draw length would have a different cable to post measurement. Any variance in string length, axle to axle length, and brace height would change that measurement as well. If there is a specific measurement I'd love to know, so if I'm wrong please help me out as well. I agree to get everything to spec and then time though.


You are correct. Jim Rumps and I talked alot on the phone about this very same thing. My TX4 has the #3 cams on it. He was a longer draw. My measurement was some thing like 7/8". His was under 1/2" I think. But both bows were shooting the correct speed. I also spoke to Richard about this and I do believe he said that they can be different. It's all about tuning and finding trhe sweet spot. It took me awhile to find mine, and when I did it was like turning on a light switch.


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## Petapal (Nov 29, 2007)

*tuning*

John & Mitch,
As I have stated in my first post which you both have in a round about way agreed upon Pearson dose not give us a dimension between the post and cable. That being said, the point I am trying to get across is that the determing factor for this mystery dimensin will be the correct length of the cables and string. Lets just say the cables and sting are a 1/2" long you may still be able to time it properly by getting the mystery dimension equal but it will not be to Pearsons specs which one would assume to be close to optimum performance. And if I remember correctly that is what this thread is all about. I was merely trying to stress you have to brueprint your bow before you can time it properly in this case. I hope this is helpful and good luck.
Bryan
By the way I have a TX-4 and a Z-34, both with the RB cams and they are fast.


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## MitchFolsom (Jan 11, 2006)

Petapal said:


> John & Mitch,
> As I have stated in my first post which you both have in a round about way agreed upon Pearson dose not give us a dimension between the post and cable. That being said, the point I am trying to get across is that the determing factor for this mystery dimensin will be the correct length of the cables and string. Lets just say the cables and sting are a 1/2" long you may still be able to time it properly by getting the mystery dimension equal but it will not be to Pearsons specs which one would assume to be close to optimum performance. And if I remember correctly that is what this thread is all about. I was merely trying to stress you have to brueprint your bow before you can time it properly in this case. I hope this is helpful and good luck.
> Bryan
> By the way I have a TX-4 and a Z-34, both with the RB cams and they are fast.


I see your point. But my point is that sometimes a bow needs to be a little out of factory specs for ultimate performance. Now I'm not saying if the factory ATA is 33", then 35" is alright as long as it shoots good. Not saying that at all. Sometimes a 1/2 here and a .25 there is not really killing performance. I don't think any of my bows are what the factory has written down. I tune mine for me, and what shoots good.

But if you want to go with factory specks, take the string and cables off. Twist/untwist until they are factory. Reinstall them and go from there.

We're all doing the same thing, but just different.


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## Bert Colwell (Jun 25, 2005)

OK guys, this is blowing my mind. It my original post, I stated the draw felt short. I installed a new set of Winner's Choice strings this morning. Before installation, I double checked all the legnths. They were all right on the money. After a few minor tweaks of the cables using a draw board, I had the axle to axle, brace height and timing dead on. I shot it through the chronograph to see if anything improved, and it was still slow. I don't know why I didn't do it sooner, but I put it back on the draw board and measured the draw length. This thing meaures 27.5", but it has 29" cams. I am lost. Shooting a 350 grain arrow at 70 pounds, it is shooting 305 fps. This is exactly what I would expect it to shoot at 27.5". Any ideas? Is it possible that I got some mismarked cams. According to the paperwork that came with the bow, 29" cams should be #6. That is what these cams are labled. Thoughts?


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## JuniorsOutdoor (Apr 11, 2008)

Bert Colwell said:


> OK guys, this is blowing my mind. It my original post, I stated the draw felt short. I installed a new set of Winner's Choice strings this morning. Before installation, I double checked all the legnths. They were all right on the money. After a few minor tweaks of the cables using a draw board, I had the axle to axle, brace height and timing dead on. I shot it through the chronograph to see if anything improved, and it was still slow. I don't know why I didn't do it sooner, but I put it back on the draw board and measured the draw length. This thing meaures 27.5", but it has 29" cams. I am lost. Shooting a 350 grain arrow at 70 pounds, it is shooting 305 fps. This is exactly what I would expect it to shoot at 27.5". Any ideas? Is it possible that I got some mismarked cams. According to the paperwork that came with the bow, 29" cams should be #6. That is what these cams are labled. Thoughts?


Just to confirm, how are you measuring the draw length? Also, which pegs do you have your string on?


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## Bert Colwell (Jun 25, 2005)

JohnBSox said:


> Just to confirm, how are you measuring the draw length? Also, which pegs do you have your string on?


String is on the long posts. I am measuring the draw from the deepest point of the grip to the front of the string.


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## JuniorsOutdoor (Apr 11, 2008)

Bert Colwell said:


> String is on the long posts. I am measuring the draw from the deepest point of the grip to the front of the string.


That is why. You need to take your draw length measurement and add 1 3/4" in order to get the AMO draw length. Your measurement is only to the pivot point. My guess is if you put a 29" arrow on your bow, when you draw it will come just to the front of the riser. If that is true I think you are ok.


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## MitchFolsom (Jan 11, 2006)

Bert Colwell said:


> OK guys, this is blowing my mind. It my original post, I stated the draw felt short. I installed a new set of Winner's Choice strings this morning. Before installation, I double checked all the legnths. They were all right on the money. After a few minor tweaks of the cables using a draw board, I had the axle to axle, brace height and timing dead on. I shot it through the chronograph to see if anything improved, and it was still slow. I don't know why I didn't do it sooner, but I put it back on the draw board and measured the draw length. This thing meaures 27.5", but it has 29" cams. I am lost. Shooting a 350 grain arrow at 70 pounds, it is shooting 305 fps. This is exactly what I would expect it to shoot at 27.5". Any ideas? Is it possible that I got some mismarked cams. According to the paperwork that came with the bow, 29" cams should be #6. That is what these cams are labled. Thoughts?


I think you are still a little slow. Maybe 10-15 fps. But that's alot better than where you started. Did you put your speed nocks back on? That can cost you around 8 fps on these bows sometimes.


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## JuniorsOutdoor (Apr 11, 2008)

Where do you all have your speed nocks? I've got mine at 1 3/4" from the cam. Just curious as to what's been working for you guys.


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## MitchFolsom (Jan 11, 2006)

JohnBSox said:


> Where do you all have your speed nocks? I've got mine at 1 3/4" from the cam. Just curious as to what's been working for you guys.


Same on my TX4. When I had my Z 34 they were 1.5" from cam. 3 on top and bottom.


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## MoNofletch (Jul 28, 2003)

I shoot 29" Z34 with #6 cams.
The measurement you are asking for is different with each draw length. It is more important to have the cams timed. They should be close to the intersection of the cam cut outs while on the draw board. (or close). I will try and get a pic for you.


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## mobowhntr (Jan 29, 2005)

Bert Colwell said:


> String is on the long posts. I am measuring the draw from the deepest point of the grip to the front of the string.


Measuring like that, you need to add 1-3/4". Puts you at 29-1/4" AMO draw length. About a 1/4" long. I shoot a 27.5" draw and put a mark on an arrow at 25-3/4" to check my bows draw lengths.


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