# Got a Set of Uukha EX1 EVO2 Limbs Today



## DM-SC (Jul 30, 2017)

The postman was nice enough to delivery my Uukha EX1 EVO2 limbs today. Love the looks and the way they draw, though I haven't been able to shoot them yet.

I had to put quite a few twists in my string (as compared to my previous limbs) to get the brace height to Uukha's recommended 8.5" (68" bow).

I'm assuming that is due to the more extreme curve of these compared to my previous limbs.

Anyhoo, can someone please explain why these limbs have more curve to them? What's the advantage?

Thanks!









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## ButchD (Nov 11, 2006)

The curves lighten the feel of the final few inches of the draw cycle. They primarily bend at the end of the draw, enabling a kind of let off feel. Check the brace height/ string length recommendations. The brace height seem higher than I recall.
Butch


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## DM-SC (Jul 30, 2017)

ButchD said:


> The curves lighten the feel of the final few inches of the draw cycle. They primarily bend at the end of the draw, enabling a kind of let off feel. Check the brace height/ string length recommendations. The brace height seem higher than I recall.
> Butch


Thanks, that's what I was thinking.

As for the brace height, Uukha recommends 218mm for 68" bow. My conversion from 218mm to inches equals 8.583".

BowBrace height +-10mm
74"239 mm
72"232 mm
70"225 mm
68"218 mm
66"211 mm
64"205 mm
62"198 mm
60"192 mm
58"186 mm

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## theminoritydude (Feb 11, 2013)

Recurve bows are often touted to be superior in terms of performance when compared to longbow varieties but that part is seldom explained. 

My ANALysis (*chuckle*) of the recurve phenomenon suggests that it exploits an aspect of incremental gear ratios. 

Every racer knows the importance of using incremental gear to get to high speeds. It starts from the first gear and ends with the 4th or 5th (depending on how rich you are or if you’re driving stick). Not so different in archery, whether we are talking about compounds or recurves.

Recurve works in the same principle. Energy stored in the limbs at full draw is initially transferred at the limb tip region, like a coil spring. Most of the movement at the beginning is isolated at a short length from the tip, the rest of the limb either static, or if you go far enough into the limb, you might find parts of it going in a totally opposite direction due to initial recoil. As the power stroke progresses, a larger part of the limb starts to “activate” and move. This gradual progressive power stroke mimics the low to high gear of an automobile. So this describes the cast. Let us now look at the energy storage process.

At brace, a recurve bow limb has what I would call “dead zones”. These are locations on the limb that are in contact with the string. At the initial draw, these zones are not doing any work; by virtue of the fact that no measureable displacement of the string from the limb surface exists, is evidence that it is not working. Those regions only work when the string is displaced. Hence, at the beginning of the draw, you’re really winding up the high gear, which is the larger portion of the limb, away from the tips. As you increase your draw, you eventually get to the tips, and activate the lower gears. In a reverse sense when compared to the release.

How these “extreme (Re)curves” work, is by making the archer feel like the draw is easier and smoother. If you have seen how a flat spiral spring (used in old clocks or watches)with a spring constant close to zero works, that’s what’s really happening. Spring constants measure the per unit extension with every incremental force. In a zero spring constant situation, increasing the displacement requires no additional effort other than deciding when to stop. Which is why Border was able to come up with a “let off” with some of their limbs.

On the release, these systems work their magic by carefully designing the limb profile to incrememtnaly activate the limbs from the tip, progressing to the whole limb, with very little back movement from the recoil. You may notice that when you compare an extreme recurve with a more conventional recurve, the mid section of the limbs of the extreme recurve has a flatter gradient, which helps to reduce the amount of back movement, since it is closer in gradient to the action/reaction vector of the nocking point.


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## DM-SC (Jul 30, 2017)

theminoritydude, thanks for the explanation. 

I don't understand most of it, but thanks for taking the time to reply. 

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## theminoritydude (Feb 11, 2013)

It’s ok, I hate reading too.


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## ButchD (Nov 11, 2006)

DM-SC said:


> Thanks, that's what I was thinking.
> 
> As for the brace height, Uukha recommends 218mm for 68" bow. My conversion from 218mm to inches equals 8.583".
> 
> ...


That is correct.


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## DM-SC (Jul 30, 2017)

theminoritydude said:


> It’s ok, I hate reading too.


I read just fine.

It's the comprehending part I'm have trouble with! 

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## mikeallanclark (Feb 20, 2019)

Hi

How are the limbs.

I am really tempted to buy a set, which are roughly £300 I Think (i'm in the uk)

The only thing is, did you have to buy new arrows, i read that you may need a lighter spine, which is the only thing stoppign me ordering a set( I bought a new set of ACEs last year, dotn really want to have to do that again because I have changed limbs)


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## DM-SC (Jul 30, 2017)

I really like them. They draw smooth from start to anchor (27.75" DL).

As for needing different spine arrows, it's going to depend on which end of the range your current arrows are on.

For me, my arrows were fine. I am shooting barebow with GT Traditional 600 (full length with 100gr points).

These limbs are more efficient. My gap at 20 yards is about an inch greater.

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## Montalaar (Jan 26, 2008)

mikeallanclark said:


> Hi
> 
> How are the limbs.
> 
> ...


I didn't get new arrows when switching to the Uukha limbs. While the Uukha limbs are great to draw they really start to shine for archers with a longer draw, at least in my opinion. They "feel" really "smooth" at around 32" draw (70" bow, and i usually don't like to describe such things with how they "feel") compared to many other limbs that get really hard to draw.


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## dunninla (Oct 17, 2018)

Montalaar said:


> I the Uukha limbs ... really start to shine for archers with a longer draw,


 So if i may ask, what about them shines for those with a 28" draw? I am not a particularly strong person, and i don't lift weights or exercise (against my religion  ), so I'm planning to stick to around 30# - 32# on a barebow rigged ILF riser of 25", which at the moment looks like it will be a used Nilo. I have limbs now of the beginner variety (Sanlida X9 glass/foam), but will upgrade sometime within the next year.

Given that, I am interested in whether the UUkha will *allow me to draw 2# less weight for the same velocity*, without losing consistency? It seems lots of people like these Uukha, the SF Elite carbon foam, and the MK inpers in the $250 - $350 range. Those appear to be the big 3 in that price segment that each have their fans. And after all the posts I read about the Hoyt 720 carbon problems, I don't think I would trust Hoyt for limbs.


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## lightning25 (Jul 18, 2017)

I got a set of these limbs 40# about a month ago. 
I have a 26 and 5/8 draw length.
I shoot Victory VAP1 800 (with 110 points and spider vanes) and 700 spine (120 points and XS wings) arrows.
I shoot a 14 strand D97 string.
On conventional limbs, the 800s tune at 40.54 lbs on Win & Win limbs and the 700s tune at about 42 lbs on Samick limbs.
I started with the brace height at 21.8 centimeters per their recommendation. 
I set the tiller split at 4mm and string nock at 4 mm as well.
The 800s shot well right away. In fine tuning the 800s I raised the BH to 22.1 and adjusted the plunger a bit lowered the string nock a tiny bit ½ mm and they shot better.

So I thought I’ll try and tune the 700s to those limbs and see if they’ll tune.
I set the BH to 21.5 and played with the plunger adjustment and those arrows also tuned.

Also at 20 Meters on the conventional limbs I would have to set the sight mark at about 20. With these limbs I have to set the sight mark at about 15.These limbs are faster. 
I tried the limbs with the recommended 18 strand 8125 string and they’re a bit faster still. 

There are 2 other guys here that have these limbs and one has the 1000s and they are getting the same kind of result regarding the speed of the limbs. One has a set of 28# limbs and he said his arrows are tuning as if the limbs would be a set of 33 # conventional limbs. The guy with the xcurve 1000s are faster still.

I did run into the same issue with the number of twists on a 68 AMO string (about 65 inches) in that I had to twist the string up several extra twists to reach the BH. Right at BCYs recommended maximum number of twists for that length.

I tried a string at Uukhas recommended length and that worked fine but I feel that the longer string twisted up more seems to pull smoother. That’s probably just me.

In my case the limbs turned out to be very versatile in allowing me to tune both the 800 and 700 spined arrows. 
The point is I didn’t have to buy new arrows. 

Hope this info helps you, I like these limbs, and I hope you enjoy yours.


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## mikeallanclark (Feb 20, 2019)

I dont suppose any of you guys has, or has the opportunity to shoot some UUkhas through a Chrono


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## PaulME (Jun 11, 2014)

Any comments on how these react to an imperfect release? Comments at my club by. A couple people say something that would move your shot a couple inches on other limbs moves it 5-6 in Che’s on the uukhas? I’m somewhat skeptical as some of these same people are preaching the need to be shooting 40# or more to get to 70m (and seems like they should know better).


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## PaulME (Jun 11, 2014)

Looks like I need to proof-read when using phone/tablet, autocorrect/autocomplete weirdness and looks like I can’t edit it. Stray punctuation and “in Che’s” instead of inches.


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## Montalaar (Jan 26, 2008)

dunninla said:


> So if i may ask, what about them shines for those with a 28" draw? I am not a particularly strong person, and i don't lift weights or exercise (against my religion  ), so I'm planning to stick to around 30# - 32# on a barebow rigged ILF riser of 25", which at the moment looks like it will be a used Nilo. I have limbs now of the beginner variety (Sanlida X9 glass/foam), but will upgrade sometime within the next year.
> 
> Given that, I am interested in whether the UUkha will *allow me to draw 2# less weight for the same velocity*, without losing consistency? It seems lots of people like these Uukha, the SF Elite carbon foam, and the MK inpers in the $250 - $350 range. Those appear to be the big 3 in that price segment that each have their fans. And after all the posts I read about the Hoyt 720 carbon problems, I don't think I would trust Hoyt for limbs.


Sorry, i did not see your post. If you compare your current limbs to Uukha limbs you might actually be able to achieve what you are looking for. Even on a shorter draw length you will have benefits of the more curved shape. One reason is the more efficient layout of the 'rolling' of the recurve, another thing would be the shortened moving part of the string, as it is having more/earlier contact to the recurve (which is what theminoritydude called "dead zones"). You probably gain speed (or don't lose any), as the Uukha limbs are way lighter than your current limbs, and that is actually what makes most of the speed. Less limb mass weight with a given draw weight will result in a higher velocity. I cannot comment on the SF Elite and MK Inpers, but i know that also the WNS FC-100 are said to be really good.


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## ugeiger (Jun 14, 2011)

Did not notice a big difference on arrow impact between a set of Wiawis one and Uukha 1000 on bad release. Good torsional stiffness on Uukah's. With 33 lbs OTF for both, with Uukah can keep sight fully extended at 70 meters. With Wiawis had to move the bar in by 3".


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## Roy D (Nov 30, 2019)

dunninla said:


> I have limbs now of the beginner variety (Sanlida X9 glass/foam), but will upgrade sometime within the next year.


I could not find the option to message you so sorry to derail ( an old thread ) lol but may I ask for your experiences with these Sanlida Miracle X9 limbs?


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