40 fps slow!!!

[rdmwc]

Ok, I just got my new 70# limbs and cams and roto cups! I put the cams on the limbs and they were pretty snug. When I say snug I mean they weren't very free spinning...
I just got back from the range where I had them weigh my arrow, 441 grains had them check my draw weight, 75# and my draw length is 31". I shoot a Martin warthog. I ran the numbers on an online calculator and it said I should be at 327 fps. The shop chrono averaged me at 293 fps!! What are you guys getting for numbers from your warthog? Is there anything I could do to get this thing closer to where it should be shooting?

[Ehunter]

First thing I'd do is check ATA, brace heigth, and make sure the strings and cables are at their correct length. 75# is a bit over what I would want with 70# limbs. If that all checks out, I'd look at the cam timing. I also think that 327fps might be a bit optomistic for that arrow weight. Also, what do you have on the string (D-loop, silencers, peep, etc.)? All of those slow down a bow. Give us all the info you can about the bow, and I'm sure others will pitch in too. As far as the limbs being tight in the roto cups, that's normal with the new style. Mine are a very tight fit.

[martinbowhunter]

x2 on everything above poster said

[rdmwc]

The cams weren't free turning... I would have expected them to be very free turning.
As far as measurements, my brace height is dead on, 6.25" my ATA is off though. It's at 34 5/8. I'm not sure on how to get that to where it needs to be. As for what's on my string, I have a tied on nock, tied on d loop and 2 cat whisker silences, I don't shoot with a peep. I had it chronoed before I put the silences on and after, when I had my 60# limbs on and they only cost me 1fps. As far as cam timing, I have it timed to the specs on the archerytalk.com thread on cat cam timing.

[Ehunter]

Sorry about the misunderstanding there. The cams should be pretty easy to turn. Did they send a new set of shims with the new cams? It may be that there are too many, or too thick of shims between the cam and limb. When I upgraded my old '09 Firecat, I didn't get a new shim set with the new limbs from Martin. Ended up having to use part of my old ones, as well as come up with new ones. For the ATA, you need to untwist your cables to lengthen your ATA. Do it two twists at a time in each cable. Then recheck ATA and BH. This will also lessen the draw weight of the bow a little, and slightly change the draw length. It sounds like your cables are running a little short, so untwisting them will lengthen them, getting your ATA back to specs.

[rdmwc]

The new cams didn't come with spaces, and they actually are quite snug in there little pocket. But it was like the hub on the bearing was rubbing in the limbs, as if the bearings weren't actually doing their job. What is the ATA supposed to be on the warthog because I have seen 34" and 35".

[rdmwc]

Well, I just shot about 30 shots through my chrono... average, 296.3 fps. Now my question is, is there a break in period for the cams to loosen up or something, I just feel it should be at least shooting in the mid 300 teens... like 315 I would be happy.

[rdmwc]

I just had a friend draw my bow while I watched the cams rotate. The bearing hubs are rotating with the cams, shouldn't that part be stationary as to lessen the friction from rubbing on the limbs?

[gibson 787]

I just had a friend draw my bow while I watched the cams rotate. The bearing hubs are rotating with the cams, shouldn't that part be stationary as to lessen the friction from rubbing on the limbs?

On your specs my 09 warthog with same conversion is around 312fps. My A2A and BH are almost identical to tours. Your cams should be turning freely but without any movement on axle. I think this is your problem. I would contact Martin tech, unless you feel confident about doing a little filing and sanding yourself. There is a spacer kit containing many different size spacers that Martin sent me upon request, as I had a similar problem when upgrading an 09 Moab recently.

[Spiker]

I just had a friend draw my bow while I watched the cams rotate. The bearing hubs are rotating with the cams, shouldn't that part be stationary as to lessen the friction from rubbing on the limbs?

If you have the new 'shouldered' bearings ( the bearing sticks out past the cam surface and acts as a spacer to prevent the cam itself from touching the limb) then yes - that is going to rotate with the cam. It is the outer bearing race and is pressed and staked into the cam so it will rotate with it. The inner bearing race stays stationary along with the axle.
If it, the cam and bearings, fit too tight in-between the limb forks then it could cause excess drag and lose of speed.
If you are saying that the inner bearing race is turning with the cam and not staying static with the axle - then you have a problem.