Uukha Sx50 extra long bracing height

indegold

Member
Just invested in a pair Uukha Sx50 extra long 72” after using their Evo 2 limbs.
finding that the recommended BH of 232 mm is way too short on my trusty GMX
I had to add an inch or more to get them sounding half decent. Never had any trouble with the old Uukha limbs.
Anyone got any take on this?
 

Rockets

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I've found the same. SX50's 38# extra long on a 25" Chaser Python riser. I set the brace at the recommended 232mm but the bow didn't sound good at all. Some one shooting next to me described it as "sounding angry". I've just pushed it out to 240mm and it sounds a lot better. I'm going to push it out a little more towards 242 mm which is still within Uuhka's +/- 10mm recommendation and see if I can get it better again.
 

Rockets

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Wow, 265mm seems really high. Well I think I'll be more aggressive with increasing mine then. What string material are you using? I'm using 8125. I was talking to a former member at my club who got some 36# extra long SX50's just before he left the club and he had the same issues. He's got a MYBO Elite 25" riser. I chased him up about how he was going with his SX50's now. He said he played with the brace height a lot, tried some limb savers, dampeners then he put a fast flight string on, replacing 8125. With that he was happy and was able to set the brace to the recommended 232mm. He makes his own strings and offered to make a fast flight one for me. I might take him up on that if I can't find some thing I'm happy with.
 

indegold

Member
Hi there
Thanks for reply
Yes 265mm is really high everyone tells me it looks wrong but it’s at the place where the bow is quietest
Tried a 652 (?) string which is fast flight apparently and it sounded worse!
I am thinking that the reason bows make a noise with too low a bracing height is that the string is slamming into the bit before the recurve.
These sx50 limbs do have a pronounced recurve though not as extreme as the XX things?
Would that mean they need a higher BH?
anybody who shoots with XX UUKHA limbs like to say what they found with them in regard to BH?
 

Whitehart

Well-known member
XX are the normal curve VX+ are the extreme curve but not a lot more than your SX's - the SX's sit between the XX's & last years EX1's and the VX+ & last years VX1000's.
Shooting a 72" bow uukha 27" Riser and XX limbs my BH is 23cm.

In the past I have found that VX+ & SX prefer a lower BH, but Tiller and riser choice if not uukha will have a big influence on the optimum BH. I always start with a positive tiller 4mm Nockng point is also 4mm above sq and I can see about 1cm of string groove not touching the string at BH. Also I look at the bow and ensure that both limbs have atleast a small bend if the bottom limb is flat then BH is too low.
 

Rockets

New member
Was playing again with the tune on the weekend. Set a neutral tiller and wound the limbs bolts out a turn, on advice from another club member and it’s sounding better again but more importantly it just plain feels better to shoot. He’s helped a couple of other members tune their Uuhka limbs but both were on Uuhka Pro 2 risers. We’re going to slowly increase a positive tiller and see how it goes.
 

indegold

Member
Thanks everyone. I have been playing around a bit and found that the bow is quite happy with 22 strand 8190 but BH is still high (4mm beyond UUKHA max)but sounds better and feels great.
The reduced string angle makes everything more comfortable also the 22 strand is very solid stable like shooting with a cable.
 

indegold

Member
XX are the normal curve VX+ are the extreme curve but not a lot more than your SX's - the SX's sit between the XX's & last years EX1's and the VX+ & last years VX1000's.
Shooting a 72" bow uukha 27" Riser and XX limbs my BH is 23cm.

In the past I have found that VX+ & SX prefer a lower BH, but Tiller and riser choice if not uukha will have a big influence on the optimum BH. I always start with a positive tiller 4mm Nockng point is also 4mm above sq and I can see about 1cm of string groove not touching the string at BH. Also I look at the bow and ensure that both limbs have atleast a small bend if the bottom limb is flat then BH is too low.
hi Whitehart
Yeah that’s about my tiller in my GMX
not sure what you meant in the last sentence tho?
 

albatross

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I am glad I found this thread. I shoot a Fiberbow 6.9 Driz TeXtreme with Uukha medium #32 SX 50 limbs (68" bow). I have tried a whole range of brace heights to get a 'quiet' bow without success. Other archers have said my bow sounds 'angry'. I have set the tiller at '0'. I have gone as low as 7 3/4" up to 10 1/4" brace height. I have tried 652 FF, 8125 & 8125G. Strand counts of 14/16/18 The quietest I managed to get it was with 9 7/8" (16 strand 8125G) but it is still noisy and the groups at 70M were rubbish. I have just made an 18 strand string using D97 in the hope that that material will help. A video I watched (australian archery shop) stated that Fiberbow risers were dificult to tune ands I am inclined to agree.
 
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Timid Toad

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My guess is your arrows are striking the riser. In my experience, angry bows, sharp crack noises etc are back end contact, often caused by incorrect spine also giving false tune.
 

albatross

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Definately not arrow striking the bow. It is always a harsh string noise. I had this same problem when I used to shoot a GMX years ago with an 8125 string. I found that tuning the tiller with the limb bolts as I shot each end combined with changing the string to D97 eventually cured the problem. I have tried unsuccessfully to do the same with this riser.
 

Timid Toad

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Don't forget moving the tiller bolts changes the poundage, and changing the string material affects speed and efficiency too. Everything you have described suggests too stiff an arrow, but I'll toddle away now and leave you to it.
 

albatross

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Yes I appreciate what you have written. Don't toddle away I am always ready to listen to 'genuine' advice. Not sure about the stiff arrow - but I have some weaker spine ones that I will give a couple of ends to - just to see the effect.
 

Timid Toad

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Definitely report back, yes. Also, early Fiberbows had limb slots that were prone to wear, so alignment could be variable. I don't know what your riser is like, but just have a quick squint down the string and check the limbs are still seated nice and true to the riser.
 

albatross

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Update. I shot the 6.9 today what a difference to before. I changed the setup to 4mm +tiller. Dyna97 16 strand string. Set the brace height to 9 1/4". I noticed that the nock fit on the string was 'less tight' than with the 8125g string - which may have accounted to some of the noise. I arrived at the +4mm tiller by setting the tiller to '0' then reversed the limbs and measured the tiller. It came in at 8mm. So iI halved it and set it to +4mm. I tried 6 twists above and 6 twists below the 9 1/4" - both made the bow noisier. Job done I hope.
 
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