Bow Tuning – Basic Setup

IMG_7304For a beginner, if you purchased your bow from an archery shop, hopefully they worked with you to “basically” setup and tune it for you. If you are in the unfortunate situation were you do not have a pro shop near by and/or purchased your bow online you will need to perform the basic setup yourself. This may be a difficult task if it is your first bow and you are a green horn to archery. Shooting form has the most impact on your performance and you need to be relatively consistent to see any major impact from bow tuning.

That said in the first couple of blogs, I will give a basic overview of how to setup your bow so you can begin shooting with it. Later in the series we will discuss the intricacies of tuning each area of the bow.

For any bow setup you should have a couple of basic bow tuning tools

IMG_7604Bow Square: T-shaped tool for measuring brace height, tiller and nock position.

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IMG_7606Nock Pliers:  Specially designed pliers for installing nock points.

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IMG_7608Bow Stringer: Provides a safe and convenient way to string recurve or long bows.

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You may also need an Allen Wrench Set (Hex Keys), Pliers, adjustable wrench, scissors and/or various screwdrivers depending on the composition of your equipment. Reference the manufacturer’s manuals for necessary tools. There are a ton of additional bow tuning tools such as a pressure button measuring tool, bow scale, electronic chronograph, bow press and leveling tools. These are optional and will not be used for the basic tuning.

Completely assemble your bow, for a quick and simple step-by-step guide check out my earlier post about Putting an Olympic Bow Together.

Make sure you gather all the pieces that you are going to use including the riser, limbs, stabilizer system, string, nock, arrow rest, sight, clicker and plunger. It is important to start with everything when tuning, since even one change can have you starting all over again.  Start by making sure that all the pieces fit together, and are correctly assembled so you have a tight fit.

In the first blog we will make sure your limb alignment is correct, the string and brace height are within specifications, and the tiller is properly set so the limbs are correctly set. Olympic bows are typically take-down bows with risers that have International Limb Fittings (ILF) so you can easily replace them. It is very important that limbs are aligned straight and that both limbs are aligned with the center of the grip. Some risers ILF slots can be adjusted side-to-side and you may need to make some adjustments to align the limbs.

limb_align2

For good limb alignments the things to check are…

  • The limbs are correctly installed and the top limbs in the in top slot, and bottom in the bottom. (this may sound obvious but it would not be the first time someone got their limbs mixed up)
  • The string is lined up with the center of each limb and the center of the grip.
  • The limbs are not twisted – check out my earlier blog about Twisted Limbs.

brace-heightNext we need to make sure you are using the correct string for the bow. This is measured using the brace height or the distance between the center of the string and the grip when the bow is strung using a bow square. Each bow manufacturer provides the specific tolerances for the brace height however the following chart is a pretty good guide.

62” Bow            7 3/4″ – 8 1/4″              197 – 210 mm
64” Bow            8” – 8 1/2”                    203 – 216 mm
66” Bow            8 1/4” – 8 3/4”              210 – 223 mm
68” Bow            8 1/2” – 9”                    216 – 229 mm
70” Bow            8 3/4” – 9 1/2”              223 – 242 mm

If your brace height is just slightly out of range you can try to add a couple of string twists to adjust within the specific tolerance however never put more that 20 twists in a string.

tiller-measureNext we need to make sure the correct amount of draw weight is shared between the limbs. The difference between the top tiller and the bottom tiller will effect the bow reaction on release and your ability to hold steady at full draw and aim. Your hand on the grip is centered in the bow however your arrow is actually above center, the bottom limbs needs to be slightly heavier to compensate. This is accomplished on an Olympic bow using the adjustable tiller. Most risers are shipped with the tillers adjusted to the correct depth. Adjusting the tiller is an extremely advanced bow tuning technique, and should ONLY be adjusted by a someone with experience. The thing for you to check is to make sure that top tiller is about 1/8” to 1/4″ (3-8 mm) greater than the bottom tiller, if not take your bow to a professional pro-shop or coach to help you adjust it.

In the next post, we will cover installing the arrow rest, nocking point and setting up your center shot.

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My Bow

IMG_7304Recently, one of my Tumbler followers asked me to share the details of my competition bow since they were moving towards competitive archery and wanted to know about my bow. First, I will explain the story of how I got to my current bow.

I have been searching for the perfect bow for me since the day I started shooting. Finding the perfect bow takes experimentation, trial and error. Your bow is a personal preference, so much so that in ancient times, it was a person’s most treasured possession and many kings were entombed with their bows. Finding the perfect bow may take years… and it may change as you grow, change and develop.

When I was just starting out at 9 years old, I needed a light mass weight bow. Something that would not damage my bow arm long term however would allow me to practice a lot. I was a good shot however VERY small for my age. I was able to come across the Fiberbow riser with a mass weight of only 599 grams, less than half the weight of other bows and it allowed me to practice a lot with less fatigue. This was a great bow until a couple of years ago, when I became stronger than the bow.

So before training for the Canada Games, I switched to the Cartel Midas 25” riser. I love that bow, it helped me win a Silver at the Canada Games and it took me to the World Indoor Championships in Las Vegas . This was an awesome bow for me as a cadet, however, with the change of divisions and greater distances as a junior I need to generate more power for outdoor shooting. Therefore I switched to a 23” Midas Riser and increased my limbs to 36 pounds. On initial tests I was able to top 196 feet per second and had to add additional weights to consistently settle on 194.5 fps. This is high for a recurve archer with only a 25” draw length.

IMG_7317My new bow is as follows…

  • 23” Cartel Midas Riser
  • 36# MK Archery Medium 1440 limbs
  • Cartel Spectra Sight
  • Cartel XD Stabilizer system with Midas V-bar
  • AAE Extended Clicker
  • Cartel Rest
  • Cartel Cushion Plunger
  • Custom String

Wow, this bow is amazing; I hardly feel the shot. The limbs are the smoothest I have ever shot. The limbs use carbon foam-core technology and are extremely smooth and straight. I love my new bow and it is the perfect bow for me right now. Although bow selection takes time and experimentation I hope you too can find the perfect bow for you.

Arrows Series – Part 3: Draw Weight

Obviously, force is required to move the arrow forward off the bow and it is generated from the tension of the limbs through the bowstring. Therefore, when purchasing arrows you need to know your draw weight so you can purchase the correct corresponding spine size for best performance. Limbs stiffness is determined by the amount of force, measured in pounds, required to draw the bow to a 28” draw length as outlined in the following Archery Trade Association (ATA) standard.

AMO BOW WEIGHT STANDARD

For Conventional Bows

Bow weight is the force required to draw the nocking point of the bow string a given distance from the pivot point of the bow grip (or the theoretical vertical projection of a tangency line to the pivot point parallel to the string). Draw length from pivot point shall be designated as DLPP and shall be referred to as TRUE

DRAW LENGTH.

For the purpose of uniform bow weight designation, bow weight is the force required to draw the bow string 26 1/4” from the pivot point. This weight will be marked on bow as being taken at 28” draw (26 1/4” plus 1 3/4” = 28”) See DRAW LENGTH STANDARD.

EXAMPLE: Weight Adjustment Range: 45/55 lbs. Weight Set At: 50 lbs.; Hold 32 lbs. Draw Length Range: 29” – 30”

EXPLANATION: The pivot point is a more realistic measuring point (when compared to the variations of profile of the back of bows at the handle section) for establishing bow weight since the pivot point is a constant in all bows as well as the contact point of the bow hand from which the true draw length is generated.

The 26 1/4” DLPP is the approximate equivalent of the 28” draw used previously on the more massive wooden handle bows.

Therefore, your draw weight is a combination of your draw length (See Arrow Series – Part 2 Measurements) and the combination of your riser (23” or 25”) and your limb stiffness (15#-50#).

For example, a 25” riser with a 34# long limb produces a 70” bow with a draw weight of 34 pounds at a 28” draw length.  If these same limbs were used on a 23” riser, the combination would produce a 68” bow with a draw weight of 36 pounds at a 28” draw length.

However, not everyone has 28” draw length, especially young archers whose draw length will change progressively with growth. So as a rule of thumb you can add or subtract approximately two pounds for each inch your draw length is over or under the 28” standard.

Using the previous example, if an archer has a 26” draw length and uses a 25” riser with 34# long limbs it will produce 30# of force at full draw OR uses the 23” riser with 34# long limbs it will produce 32#.

This is very important to select limbs that enable you to develop and compete however do not cause long-term physical damage. When purchasing limbs you need to determine if the limbs are too heavy, you can try this simple 7-second challenge.

7-second challenge

  1. Draw the bow to the anchor
  2. Hold seven seconds
  3. Let down without lowering your hands, stay in set-up position to take a 2 sec brake,
  4. Repeat several times.

If you cannot do it properly then the limbs are too heavy for you. If you find this challenge extremely easy, you can look at heavier poundage limbs, if you choose.

Now you understand draw weight and used in combination with your draw length you can see the arrows that match your equipment using a manufacturers arrow selection chart. In the up coming blogs we will try to examine the arrow spine, flex and stiffness.

Putting an Olympic Bow Together

There are only five steps to putting an Olympic bow together, however if attention and caution are not used you can inadvertently damage your bow or potentially yourself.

Step 1: Determine Riser and Limb Position

It is important to make sure the limbs are properly installed in the riser. If the limbs backwards (top in the bottom and bottom in the top) your arrows will fly low and inconsistently. Most set of limbs are marked top and bottom and are usually marked near the poundage information.

Quick tip:  Usually lower limbs has the label on the inside (convex side) and top limbs has the label on the outside (concave).

Step 2: Attach the Limbs to riser

Start with the riser upright and attach the limbs.

For international limb fittings, insert each limb into their associated limb pockets (top on top, bottom in bottom) applying enough pressure for them to sit securely (usually you will hear a click noise).

For other “pro-style” limb fittings, slip the limbs over the bolts and into the limb pocket. Attach the bolts for the limbs and tighten until secure. (Be sure not to over-tighten).

Step 3: String the bow

Attach the string to the bow using a stringer. Start by comparing the loops on the ends of string and, using the largest loop, slide the loop over the top limb and down about halfway. Then, using the small loop of the string, slide it over the tip of the bottom limb.

Quick Tip: Refer to the manual for your stringer and adjust these instructions accordingly.

Although stringer styles and use can vary, here are some basic steps.

  • Place the stringer’s large pocket over the bottom limb tip and string, making sure the string is in the string grooves.
  • Next, attach the stringer’s small pocket over the top limb
  • Step on the stringer below the riser and lift the riser from the handle
  • Slide the string along the top limb until the top loop sits in the string grooves
  • Slowly, lower the riser to allow the limbs to apply tension to the string

Safety Tip: Before removing the stringer, proceed to the next step…

Step 4: Double check the string, limbs and bow

The most important step in my opinion is the bow double check, since you can damage your bow or worse yourself if not preformed.  First, check the string is in the string grooves on both limbs and then make sure the limbs are completely set into the limb pocket.

Safety Tip:  A safe way to verify the limbs are set correctly, place your arm along a limb, grab the tip and slowly bend the limb back. If you hear a click (or nothing) the limb is correctly set in the limb pocket. Repeat for the both limbs.

Step 5: Attach Sight and Accessories

Lastly, you can attach your sight and other accessories such as your stabilizer system. Now you are ready to start warming up and begin shooting.

If you do not have a stringer yet, Cartel Doosung has a couple of great options of stringers available for very reasonable prices.

MK Archery Vera Limbs

Every bow requires limbs, most beginner, and some intermediate bow kits come with limbs. If an archer moves towards competition archery, they will want to upgrade this essential element. Designers of limbs strive for an ideal combination of speed, stability and smoothness when deciding what materials to use and how to combine them.

Modern recurve limbs are made from multiple layers including fiberglass, carbon and/or wood and usually are laminated over a core of wood or carbon foam. A good archer will be able to shoot well with any good set of limbs, no matter the composition and elite archers often have a selection of various types for different training purposes, they usually gravitate towards one.

Foam-core limbs are more resistant to warping, are usually lighter and are not affected by humidity and/or weather conditions. They provide a consistent straight smooth pull curve and a faster shot. Carbon foam-core limbs are usually a lot more expensive and require a lot care. Archers need to inspect and repair even minor imperfections as they can lead to massive failure. Whereas, Wood-Core Limbs are usually far less expensive than foam-core, and are usually more durable. Although they usually have, a little more mass weight they can deliver a slightly higher speed with the same poundage as foam-core limbs.

Manufacturers produce limbs in various strengths or draw weights to service all types of archers and are measured in poundage (#) at a certain draw length (usually twenty-eight inches) and by length of risers.

Example is 66”-34# @ 28” or 68”- 32#@28”

Since not all archers have the same draw length, the same limbs will be different for each archer. The same set of 34# limbs for an archer with a 24” draw length will pull less than 34# and an archer with a greater than 28” draw will pull more than 34#. You can easily determine your draw weight using a bowscale at your local archery shop.

Limbs also come in various lengths that will determine the overall length of the bow which may be a factor for shorter archers.  This chart can help you determine which length to order.

Riser Size Long Limbs Medium Limbs Short Limbs
23” 68” 66” 64”
25” 70” 68” 66”

Limbs use to be designed specifically for the manufacturers riser and once you purchased a riser you were bound to that manufacturer for limbs or you would have to change both limbs and riser. Now most manufacturers use International Limb Fittings or ILF and are an unofficial standard that allow limbs manufactured by different companies to fit on the various risers.

There are several great manufacturers of limbs and in 2010 MK Archery started producing a great set of competition limbs.  Currently holding world records in recurve men with scores of 1386 for FITA and 342 for 90M. The two top of the line models are the MK 1440 (foam-core) and VERA (wood-core).  The limbs are made from multiple crossed carbon layers, laminated over a foam or wood core. If you are seriously considering investing in a good set of limbs, consider some from MK Archery.