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View Full Version : How do you read the Cam Chart?



la4ge
04-02-2008, 07:28 AM
A friend of mine bought a Martin "Mag Cat" at Dick's and said it was "Last Years" model. I'm trying to get some info on the Bow but the Cam charts seem a bit cryptic to me. Here is the info on the Sticker. Can someone tell me what it means and how it is derived from the Cam charts. Specifically, can one look at the info below and determine the year of the bow and the draw length and range?
Draw: MP
Bow: 0543318
Let Off: H
Shoot: 87.5 (String)
Split: 35.75 (Cable)
Cam Mod: F5

bfisher
04-02-2008, 09:13 AM
It's not hard to figure the year of manufacture. The bow has an MPro cam on it, right? Then it's either a 2007 or 2008 model. The MPro came out in 2007. The 2007 model had a silver/grey cam. 2008 carries a black cam with a slot for a draw stop.

I looked the Bow Cam charts at string/cable lengths and his bow isn't on there. Often times bows are made for stores like Dicks and are just slightly different than standard models. Usually a slightly different riser configuration which changes the specs. That's why you can't find the info for it in the charts.

I'm not all that familar with the bows Dicks sells, but might be able to answer questions of a specific nature. What do you want to know?

Barry

la4ge
04-03-2008, 10:15 AM
Very helpful. Thanks. The specifice question is: From the info on the sticker, can I tell the draw length. I'm guessing it's 30", but I'd like to be sure from the data provided by Martin. The cam module is an F5, which is conspicuouly blank for the String and Cable lengths in some places on the chart and in other places its 29" or 30". The sticker says 45-60#, but with the limbs snug, the best I can get is about 50#. I'm a seasoned bowhunter, but new to the Martin line, but they seem like really good bows for the money. Light, Fast and not overpriced.

bfisher
04-03-2008, 11:18 AM
Very helpful. Thanks. The specifice question is: From the info on the sticker, can I tell the draw length. I'm guessing it's 30", but I'd like to be sure from the data provided by Martin. The cam module is an F5, which is conspicuouly blank for the String and Cable lengths in some places on the chart and in other places its 29" or 30". The sticker says 45-60#, but with the limbs snug, the best I can get is about 50#. I'm a seasoned bowhunter, but new to the Martin line, but they seem like really good bows for the money. Light, Fast and not overpriced.


OK, something is wrong. The weight should be higher. If you back the limbs out you should be able to see a number and letter near the butt of the limb. See what it is and tell me. I didn't see any limb numbers listed on the chart like prior years. SUCKS!!!!! It could be something as simple as the rigging being not twisted up enough to preload the limbs, but 10# is a lot.

As for the draw length, measure the axle to axle length and see what it is. I think the bow should be close in specs to the Bengal so compare to that. Just about any bow with a similar A2A length and same cam should use the same module for the same draw length. So the F5 mod should be OK for 29", but I'd actually measure the bow at full draw and see what it actually is.

Now I'll give you the best advice I can. Call customer service and ask for Jake or Joel. Pose your question to them, especially about the draw weight. Don't forget to get the limb number first. They may tell you to take it back to Dicks. I don't know. Or if you'd like you could PM Jake (aka PUG) on www.archerytalk and see what he says.

Hope this helps.

la4ge
04-03-2008, 12:39 PM
This is what I love about the archery community. No BS, just helpful information from unkown friends. Thanks again. The Limb numbers are 31 and the ATA length is 32.75. after I loosened and retightened the limbs, I now get 55# max, out of them, so the draw weight issue may just be the rigging as you suggested.

flytier17
04-03-2008, 12:57 PM
I think you mean 3L by that. The "L" means that it will most likely bottom lower than the peak weight, but only 2-3lbs.

bfisher
04-03-2008, 07:18 PM
Alec, you are right about part of your answer, but maybe wrong about the second part.

Yes, these are most likely 3L limbs. But even 3L should give the 60# if that's what Martin determined. Just that 3M and 3H would be somewhat higher. Next limb down would be 2H which should be about 58#.

la4ge, I've got a notion that the rigging isn't as tight as it should be. If the bow is anything close to the Bengal then the A2A should be closer to 32". Were the bow mine I would do as I stated before and twist up the rigging to put more preload on the limbs, if you have a press.

If the draw length is OK then take a pencil and mark the side of the cam where it passes through the limb fork. Use this as a reference for draw length (cam orientation). Then put about five twists in the cable and ten in the string. Put it back together and check the mark to see if it's close. Now check the weight, A2A and brace height to see how much they change.

I might also ask you a question now that I've typed all the above. What scale are you using to weigh the bow? If it's a Cardoza then the bow might be OK. The hand held Cardoza is notorious for showing about 4-5# light.

Keep us posted, please.

la4ge
04-04-2008, 11:20 AM
I'm using a Bear Archery "Tru-Weight" bow scale, which appears to be pretty accurate to the to shop scales that I've tested my own bow with. I'll try tightening the rigging, and see if I can get it to 60# Thanks again for all the great info.

flytier17
04-04-2008, 11:50 AM
OK, sorry I got that wrong.

According to the Tech info, his bow should be 32 1/2" A2A. I jes got that of the tech info page.

bfisher
04-04-2008, 02:50 PM
Well, I knew it was 32 something. Just goes to show you what I know. That's what's wrong with specs. My FireCat is supposed to be 33" according to the book, but it came out of the box at 32 1/2". I could probably change it and lengthen everything which would lighten the preload on the limbs and drop the brace height, but I got the string so there is no peep rotation and I hate to mess with it.

Besides, my body has a lot of healing to do beforeI'll be able to appreciate the effects of tweaking. Maybe some time this summer.

scepterman30x
04-07-2008, 10:08 AM
I think you mean 3L by that. The "L" means that it will most likely bottom lower than the peak weight, but only 2-3lbs.


I would like to clarify some confusion about how to interpret Martins limb nomenclature. It is very simple, it has nothing to do with peak or what the bottom will be; the limbs are numbered with a number and a letter. What this means is that in between each numer you will have a difference of about 5 lbs. of weight. in between each letter it is a difference of about 2 lbs. in weight. So if your set up for instance is pulling 53 lbs. with the limbs bottomed out with 3L limbs and you want 60lbs. you will need a limb deflection code of 4M ( one number higher=5 lbs. and one letter higher=2 lbs. for a total of 7lbs.)

If you need to go up 5 lbs. all you need is one number higher which would make it 4L.

If you need to go up 2 lbs. all you need is one letter higher which would make it 3M.

It works in reverse also if you want to lower your weight.

flytier17
04-07-2008, 07:26 PM
OK, thanks.

igorts
11-19-2008, 11:56 PM
i know that tread is old, but wanted to add that first 2 digits in serial stand for a model year , in this case 2005:D