I just got a set of Ex1 Evo2 longs at 32# and cannot seem to get the vibration out of them. Theyre on a Gillo G1 riser. I've tried brace heights from 8.2" up to 9 and also wound the tiller bolts from about half out to almost full in. The limbs vibrate like tuning forks for a few seconds after a shot or even a pluck on the string. Should I just try getting more radical with the brace height? I've used two different strings as well, one BCYX with plenty of twists in it and an 8125g with almost no twists in it.
Uukha limbs with Gillo riser
Warmuth
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I just got a set of Ex1 Evo2 longs at 32# and cannot seem to get the vibration out of them. Theyre on a Gillo G1 riser. I've tried brace heights from 8.2" up to 9 and also wound the tiller bolts from about half out to almost full in. The limbs vibrate like tuning forks for a few seconds after a shot or even a pluck on the string. Should I just try getting more radical with the brace height? I've used two different strings as well, one BCYX with plenty of twists in it and an 8125g with almost no twists in it.
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In my case, uukha limbs sound better bolted in, especially if the arrows are on the weak side. Brace height is always high for me which is uncommon. I could only decrease the vibration with weight on long rod while using a back stab as well, but Im interested in how barebow handles the vibration.
I went up to 9.25 and they sound better and vibrate less but still oscillate after the shot. I may try a bit more BH since going up did seem to help. The draw on them is very nice and was the main reason I got them so I'll figure out how to settle them down one way or another.
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I have a G2 riser and long Uukha Ex1 Evo2 in 34#. I run a flemish 8190F string and shoot a 8 7/8” BH. I have a set of limb savers on it and it doesn’t jump around anymore. Doesn’t sound like a .22lr going off now either.
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I have a G2 with Uukha limbs and must say they are a bit boingy, but Limbsavers quiet that down a bit. Shooting tiny VAPs and stringwalking I figure there is no way the thing will be quiet. Keeping plenty of mass weight on the bow is nice too - either the brass weight or the aluminum weight plus internal weights - seems to isolate the limb vibration from the hand. It shoots like you are holding a brick, very solid and relatively dead in the hand, but I think that also kind of leaves the limbs out there to flap around a bit. Brace height is at 8 7/8" on a 25" riser, string is D75 endless loop, arrows are .500 VAPs with 120gr points with 2" vanes.
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Also Astro flight string is definitely has less noise but slower.
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Uukha limbs like higher brace heights. 9+ might be the way to go. I shoot about 8 3/4" on my Vx1000's. It could also be the tiller. People often look over tiller as the vibration culprit. If your tiller is off, the limbs are not launching simultaneously so after the shot they oscillate back and forth because one limb came back to brace height before the other. Its like shooting a compound with mistimed cams. Sometimes the recommended tiller setting doesn't work. Just depends on the set up. You may actually need to go outside the recommended range to get it to tune. They're usually just starting points anyway.
I learned how to find the sweet spot for tiller from an RA at the Olympic Training Center and the method has worked well for me ever since. You are shooting BB 3 fingers under, but the process is the same I would think. I could be wrong but this is just my suggestion.
-Take any weights off the bow and shoot it as a raw bare bow, just riser, limbs, rest, and plunger.
-Shoot a few ends, keeping your technique as consistent as possible, all while paying attention to how the bow reacts. Make sure you're not grabbing the bow at all.
-If the bow tends to consistently kick upwards, you have too much negative tiller because the bottom limb is reaching brace before the top. Vice versa for the top limb.
-Start adjusting by backing off (or driving in, depending on the reaction) the tiller bolts 1/8 turn at a time until you get a consistent neutral reaction where the bow doesn't kick up or down, but straight forward.
At this point, the bow should be much quieter.
Again, this method is used by Olympic shooters using split method but maybe it will work for you. Bare bow experts feel free to correct me...
I'm certainly not opposed to trying that. I'll admit I set zero tiller for no other reason than that it's just the common way people are told to set it for three under. I do have a friend who is a bowyer and he has a tillering tree that tracks nock travel so that's worth a shot as well, should reveal a limb imbalance.
Something to check, I had the same issue, what I found was that the UUKHA limbs were not really seated all the way. The U notch in the limbs as just slightly too narrow to allow the Gillo bolts all the way in, a small amount of sanding in the limb notches fixed the issue the limbs fully seated and the vibration was eliminated.
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Try with a negative tiller of 2-3mm and you may be surprised (in a good way).
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Have a G2 and Uukha lims, had some vibrations as well. Able to take most of the vibration out with brace height adjustments. At 8 7/8 “. Hope this helps
It sounds like you're already within the zone after your recent adjustments, assuming you're using a 25" riser. But just for reference, here's the suggested brace heights from their manual:
G1-27
-68" bow (short limbs)-------> 8" to 9"
-70" bow (medium limbs)---> 8 3/4 " to 9 3/4"
-72" bow (long limbs)--------> 9 1/2" to 10 1/2"
G1-25 / GQ-25 / G2
-66" bow (short limbs)-------> 8" to 8 3/4"
-68" bow (medium limbs)---> 8 1/2" to 9 1/4"
-70" bow (long limbs)--------> 9 " to 9 3/4"
The manual can be found here: http://www.gilloarchery.it/gillo-g1m-25-.html (https://www.dropbox.com/sh/8bc3vrdv...H7VDInkR65Q-ReMa?dl=0&n=154593104&oref=e&preview=GILLO_Riser_Manuale_EN_500.pdf)
G1-27
-68" bow (short limbs)-------> 8" to 9"
-70" bow (medium limbs)---> 8 3/4 " to 9 3/4"
-72" bow (long limbs)--------> 9 1/2" to 10 1/2"
G1-25 / GQ-25 / G2
-66" bow (short limbs)-------> 8" to 8 3/4"
-68" bow (medium limbs)---> 8 1/2" to 9 1/4"
-70" bow (long limbs)--------> 9 " to 9 3/4"
The manual can be found here: http://www.gilloarchery.it/gillo-g1m-25-.html (https://www.dropbox.com/sh/8bc3vrdv...H7VDInkR65Q-ReMa?dl=0&n=154593104&oref=e&preview=GILLO_Riser_Manuale_EN_500.pdf)
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In general, tiller should be 0 to natural positive (the one built in the pair) for Recurve Olympic, were bow rection can be controlled much easily with stabilizers. For BB, controllig the reaction by weights has limited range of interevent, because of the 12.2 cm ring rule, and tiller adjustment becomes very important. As drawing line in BB stringwalking is much lower than in recuve split fingers, negative tille becomes a must to get agood syncro between limbs. So, basic tiler should be 0 to natural negative (usually reversing limbs upside-down), but as a starting point only.
Then tiller needs to become much more negative depenting from grip used and distribution of weights. Typical BB archer tends to control tilting and syncro by increasing bottom weight, but this has a very limited effect if weight is not added far to the front, and will easily end up adding too much internal weight to the riser, getting it unbalanced on the vertical axis without significant effect on synchro.
Things are a bit different for asymmetric risers (G1-27 and the Luxor 27), as center of pressure on hand is almost on the line of draw (if you use the original grips) and therefore 0 tiller may work without too many adjustments.
Noisy bow comes mainly from
- wrong tiller
- wrong brace
- Tiller bolts unloaded too much
- Not enought turns on string
Then tiller needs to become much more negative depenting from grip used and distribution of weights. Typical BB archer tends to control tilting and syncro by increasing bottom weight, but this has a very limited effect if weight is not added far to the front, and will easily end up adding too much internal weight to the riser, getting it unbalanced on the vertical axis without significant effect on synchro.
Things are a bit different for asymmetric risers (G1-27 and the Luxor 27), as center of pressure on hand is almost on the line of draw (if you use the original grips) and therefore 0 tiller may work without too many adjustments.
Noisy bow comes mainly from
- wrong tiller
- wrong brace
- Tiller bolts unloaded too much
- Not enought turns on string
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