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Long live the Duallys
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Discussion Starter #1
Question for BH tunning


Dual cam bow

62 lbs
28" draw
27" 400 gold tip arrows
100 grains up front plus insert tried 85 they seem better
3 inch fusions
these arrows weigh app 320 grains with 85 grains up front

I recently had this bow dialing bh out to 50 yards
But now 20 and 30 are reasonable(BH just right about one to two inch) and at 40 the bh start drifting right 6" to 8"
I know that indicates a weak spine so i have tried a stiffer shaft light speed 340 and it seems the result is worst they weigh 360 grains

I have timed and checked the lean on the cams and they are reasonable both at rest and at full draw using a draw board. If i lean them more they will not fall into the tracks on the mods with out that noticable click

My question is with dually bows can this be fixed buy twisting the yokes if so which side right or left?
Is there such a thing as not enough lean?

Thanks for any help
 

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Long live the Duallys
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Discussion Starter #2
My walk back with field points is fine to 50

Just for your info
Anyone
 

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She's baaaaack!!!!
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Have you tried bare shaft tuning?

Can you cut .5" off the shaft?

What kind of rest are you using?
 

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I would try a few different broadheads. Some just don't fly well.
 

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The faster the bow, the worse the fixed blade heads will fly. If you think you are getting a weak shaft, take a turn off the limb bolts and see what happens. Sometimes slowing the rig down is not a bad thing. I would rather have a 270 fps bow that drills than a 290 fps bow that is unpredictable at best. This also will help you identify a sweet spot for the spine.
You mentioned yoke twisting. Do your cams lean at rest? Best idea is to have them dead vertical at rest or even slightly tilted to the left (for a right handed bow), particularly a short ATA bow as the shorter the bow, the more severe the effect the cable guard has.
If your walkback is down the middle, then I would guess that you are just needing to take off a pound or two.
 

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I would try a few different broadheads. Some just don't fly well.
What kind of broahead are you using? fix blade? mechanical?
If fixed w/ a large blade you must increase your vanes or feathers to at least 4" and installed with a right helical. If mechanical get a stiffer shaft and I'll do the 3" vanes or feathers w/ right helical....................:darkbeer:
 

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Long live the Duallys
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Discussion Starter #7
BH flight problems

I have tried a stiffer spine going from 400 gt ul pros to 340 lights speeds

I can get the BAre shafts of the light speeds to group out to 20 yards
5 arrows all unfletched

I did have this bow shooting slick trick 85 grain heads at 40 yards with field points with small 2.3 3d vanes with the ul pros

then i messed with the bow and cam lean and now its out to the right (weak spine)

This is why i asked if the fp to bh relationship can be adjusted buy inducing cam lean and i think the answer is yes

since my last bump i have induced cam lean in only the upper cam and it seams to be better for the fixed blade broadheads slick tricks and wasp boss bullets but still to be improved, so i used Jack Hammers yesterday turkey hunting

Buy the way Jak hammers are tuff my buddy shot at a squab and messed the bh up a little so i took it and shot at a steel durm 45 gallon type and the BH held together the arrow broke at 8 inches from the back but the bh is still intack
i was impressed


Thanks
I'll try tinkering some more and post my results
 

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I have tried a stiffer spine going from 400 gt ul pros to 340 lights speeds

I can get the BAre shafts of the light speeds to group out to 20 yards
5 arrows all unfletched

I did have this bow shooting slick trick 85 grain heads at 40 yards with field points with small 2.3 3d vanes with the ul pros

then i messed with the bow and cam lean and now its out to the right (weak spine)
This is why i asked if the fp to bh relationship can be adjusted buy inducing cam lean and i think the answer is yes

since my last bump i have induced cam lean in only the upper cam and it seams to be better for the fixed blade broadheads slick tricks and wasp boss bullets but still to be improved, so i used Jack Hammers yesterday turkey hunting

Buy the way Jak hammers are tuff my buddy shot at a squab and messed the bh up a little so i took it and shot at a steel durm 45 gallon type and the BH held together the arrow broke at 8 inches from the back but the bh is still intack
i was impressed


Thanks
I'll try tinkering some more and post my results
Guess that is why you have the name you do:whistle:
 

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Fletched and 3D both have good points.

I have "taken a wrong turn" a few times in my tuning history, and sometimes it's surprising how much difference it can make. Rarely have I noticed that yoke adjustments make much difference, but I always get the lean as close to zero and work from there, timing is way more critical in my experience.

That said, BH tuning has a couple of important factors.
- The shaft must leave the bow "clean", no hi/lo/left/right bias.
- The shaft must start to spin before the BH takes over the steering.

The first is a basic tuning requirement for any bow/arrow combo.
The second has some more baggage. Speed can be a problem, and the smaller the vane, the more challanging the mission. Small vanes need more offset to achieve spin initiation. Any amount of offset produces the same spin rate, but small vanes take longer to get there. Anyone who has tried a controlled experiment with Quick Spins, and any other vane, will tell you they make a difference, especially as the vanes get smaller, and the arrows go faster. I always have a bunch on hand, but I prefer conventional vanes when I can get them to work.

The perfect shot, with perfect BH alignment wouldn't require any offset, or even any vane for that matter. In the real world vane surface area and offset, along with an adequate tuning effort will be required.

Some heads, and some arrows, are a lot harder to work with that others, from some bow setups. I never figured out exactly why. When the goin' gets tough, there's always Rockets and Spitfires.
 
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