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The Big Read for Prospective Bow Buyers and Archers



A bow's AXLE-TO-AXLE length is just what it sounds like. At the end of each limb is a steel axle which holds the rotating eccentrics (cam or idler wheel). The distance between the centers of those two metal rods (axles) is the bow's advertised axle-to-axle length.


Of course, the bow's actual physical length (measured height if stood on its end) is always considerably more than the axle-to-axle length - since the eccentrics extend beyond the axles. So don't plan to put your 32" A2A bow in a 33" bow case - it won't fit.


The vast majority of today's hunting bows have axle-to-axle lengths of approximately 32". Bowhunters clearly prefer shorter bows in today's market, and much like the 7" brace height, 32 seems to be the magic axle-to-axle number - although not nearly as razor-specific. Bows with axle-to-axle lengths around 34" are often considered "crossover" bows - suitable for hunting and competition use. Bows with axle-to-axle lengths of 36" or more are primarily considered competition bows.

prophecy axle to axle length demonstration photo


The market has some tolerance for even shorter bows - down to 30" axle-to-axle (commonly sold as "treestand" bows) but success for sub-30" bows has been sporadic. Bows with axle-to-axle lengths in the 25-29" range are typically youth-only models.



Ten years ago, manufacturers fought and clawed to promote their style of limbs - much like they did with cams. Solid limb proponents claimed that solid limbs offered better torsional stiffness and were more accurate than split limbs. Split limb proponents claimed that split limbs were more durable and produced less hand-shock than solid limbs. On the left side of your bowhunting magazine, an advertisement told you how much better split limbs were than solid limbs, while on the right side a competitors ad said the exact opposite. Very confusing.


Here at the pro-shop, we weren't sure what to believe, but in those days we sure did fix a lot of broken limbs. As an authorized warranty service center, we've replaced a lot of cracked, splintered, and delaminated bow limbs over the years. Limbs of all types seemed to come apart, sometimes catastrophically, and it was our job to fix them. But in recent years we're starting to feel like the Maytag repair man. We haven't seen a really major limb failure in the last several years. Limb materials, technologies, and fibers are simply getting better. So as a matter of durability on today's bows, we think the point is moot - regardless of the limb style.


Over the years, many of those same lecturing manufacturers have crossed their own lines in the sand, and changed some, or all, of their bows to split from solid, or to solid from split. Several manufacturers now use a mix of solid and split limb styles, and little to nothing is said about limb style choice in today's publications. Until someone tries a triple limb - or perhaps a Limb & 1/2 - we'll just have to let this old battle go. Strangely, customers seem to have largely abandoned their limb prejudices as well. We get very few questions about split vs. solid limbs today.

split and solid limbs


But we can make one observation about the trends. All of today's really fast 340/350 fps speed bows seem to be utilizing a similar limb concept - what we loosely call the Willow Tree limb. These limbs are highly preloaded split limbs which seem to move up and down like pulling on a flexible willow tree branch. The entire limb seems to flex in a smooth flowing curve - rather than how a stiff diving board flexes. We suspect this is why these Willow Tree split limbs seem to be the currently favored trend - particularly on the performance bows. They may have an efficiency edge in certain configurations. But since nobody is really talkin' smack about it, we'll not stir up any trouble.


martin split limb bow

Split limbs may also be getting more action these days because of the popularity of yolkless cam systems. When a bow's cables are pulled to the side by the cable slide or roller guard, this causes some torque at the cams resulting in cam lean - particularly on the top cam. This normally isn't a problem if the bow has a split-yolk (y-cable). One side of the yolk can simply be twisted up a little to shorten it slightly and equalize the imbalance. But since many bows now feature cams without split yolks, cam lean is more problematic. Of course, small amounts of cam lean are technically inconsequential. However, the appearance of that leaning cam drives customers bananas. Customers assume its a defect - and blame every miss and burp the bow makes on the cam lean. So manufacturers came up with a smart solution ... limb biasing - which is pretty easy to do if the bow features split limbs.


To get those cams to stand upright and to offset the cable tension torque, manufacturers simply install a slightly stiffer limb on the outside of the bow (opposite the cable slide). So, many split limb bows actually have left and right side limbs with slightly different deflections (strengths). We're not sure how wise that is for actually shooting the bow. Logic would seem to suggest that two limbs working in unison would be more effective than two deliberately imbalanced limbs, but perhaps the biased limb simply corrects an inherent flaw in compound bow design. The biased limb might actually keep things in better balance throughout the entire cycle. But whether it does or doesn't, as long as the technique keeps customers from trying to analyze their bows with a carpenter's square, it's surely a welcome solution.


bowtech patriot original


While we're on the topic of limbs, we should give a shout-out to the parallel limb concept - as it literally changed the entire industry. In 2002, we got our first look into the future with the introduction of the Bowtech Patriot. The Patriot was ... well ... different. It was framed with a long ugly riser - with a stabilizer mount that jutted out awkwardly - and it had these short little limbs. Very strange. The limbs angled back toward the shooter, and at full draw they were almost parallel with each other. Weird! NO KICK? We didn't think much of the ugly duckling Patriot at first. But when we shot it, we noticed that something was definitely missing ... hand-shock. The Patriot didn't jump from your hand like most bows. It really didn't kick much at all. The bow didn't thrust forward - no violent jerk - it was greatly subdued compared to other bows of the day. Noise and vibration were also greatly reduced. Clearly Bowtech was on to something.


On a standard D-shaped bow, the limbs spring forward (away from the shooter) when you fire the bow. Since the limbs are hard-mounted to the bow's riser, the inertia of the limbs drag the riser forward too - which the shooter feels in the grip as an abrupt jerk. This is commonly described as hand-shock, and the faster a bow shoots - the more hand-shock you generate. But Bowtech's solution literally changed the whole game - the whole market. By orienting the limbs so they flexed up and down in a vertical motion, rather than back and forth in a horizontal motion, the net effect on the riser was neutralized. The top limb sprang up when fired- the bottom limb sprang down when fired - and the riser wasn't jerked forward. The opposing forces seemed to cancel one another. Finally we had a solution for hand-shock that treated the cause, rather than the symptom.


going too far with parallel bow limbs

Remember how we said that any useful innovation doesn't stay exclusive to one manufacturer for long? The year after the Patriot was introduced, several competing manufacturers swooped in to lay their claims on the parallel limb concept. A couple competitors even predictably claimed THEY had, in fact, invented the parallel limb bow, but it didn't really matter. The little batwing bow shape spread like a brush fire. Two seasons later, parallel limb bows were everywhere, and hand-shock, as we knew it, was becoming a thing of the past. Today, any bow without a parallel limb profile is either a youth bow, a very cheap entry-level bow, or a specialty target bow. Hunting bows are almost universally parallel limb bows.


Of course, there's always somebody out there willing to take a good idea too far. The idea of the parallel limb is to get the limbs moving at angles perpendicular to the bow (riser). So the center of the limb's travel arc is at 90º to the centerline of the bow - or so the logic would suggest. That allows the upper and lower limb assemblies to cancel each other's inertia. Unfortunately, even the best ideas get molested in our market. A few manufacturers have tried the MORE IS MORE method with their limb angles, assuming that if customers like parallel limbs, they'll really like super-duper way beyond parallel limbs which are practically pointing straight back at shooter's faces. What could possibly go wrong with that? Plus it looks more sic, or yj5, or something. Sheeesh!



No discussion about compound bows would be complete without covering this illusive buzz word. The word "forgiving" is easily the most abused (and absurd) word in our industry. As least words like quiet and smooth are quantifiable, should anyone really want to pull out the dB meter and the accelerometer. But the word forgiving is mostly industry snake oil. Easy to claim - difficult to dispute - and everybody can have some. And once you put the word in a sentence, it seems to blend-in like special sauce on a Big Mac ... "Our bows are up to 27% more forgiving than the competition." What? The word even leaks into other related products ... forgiving arrow rests, forgiving arrows, forgiving quivers.


Who doesn't want forgiveness? We're not perfect beings. We make mistakes. Sure, we all can use some forgiveness from time to time. So the industry applies that psych-job to archery equipment, and somehow people buy into it. Fine. The term would seem to imply that you can do things wrong, and everything will still be OK. Your shooting form and technique can be terrible, and arrows will still love you enough to hit the bulls eye. Why not? Your equipment is 27% more forgiving.


So what, if anything, does that ridiculous word really mean? When equipment is described as "forgiving," should you expect anything at all? We say - maybe. At least in our industry, the term "forgiving" really means "forgiving to human error," which is something we can't exactly measure with a dial caliper or an electronic sensor. Of course, that's the reason the term is used so loosely. If we were to test a variety of properly-functioning bows in a mechanical shooting machine, the varying axle-to-axle lengths, brace heights, cam characteristics, and grip profiles would have no significant effect on the accuracy and repeatability of the bows.

The shooting machine would shoot each bow exactly the same, each and every time. So for a mechanical shooting machine, the concept of forgiveness would be inapplicable. But if we repeated the same test with people, we might expect to find some bias. It's certainly logical to expect that, on average, shooters might be slightly more or less accurate with some designs. Surely there some levels of ergonomics and biomechanics in play here.


We're not machines. We can't shoot with perfect mechanical consistency. We bobble and we flinch. We punch our triggers and torque our grips. Even for the world's most talented shooters, accuracy is often limited to the occurrence of human error. And what makes a particular bow more or less forgiving is the bow's tendency to accentuate or attenuate these unavoidable human errors. NOW ... before we actually make a statement supporting the idea that any particular bow attribute is inherently more or less forgiving, we need to put in a disclaimer here ... If your shooting form and technique are terrible, and/or if your bow is not properly setup, tuned, and matched to an appropriate arrow, bow forgiveness - or lack of forgiveness - is a moot discussion.

The issue of forgiveness is about choosing gear that helps you to optimize your accuracy. Contrary to what the word implies, a forgiving bow will not correct your mistakes. If you're thinking that forgiving equipment is an easy substitute for learning good shooting form and technique, you're going to be very disappointed. It doesn't work that way. Even the most forgiving bow (assuming there is such a thing) will still miss the target if its operator performs poorly.


eric grippa

With that said, it is generally believed that LONGER AXLE-TO-AXLE LENGTHS are more forgiving. It is generally believed that TALLER BRACE HEIGHTS are more forgiving. It is generally believed that a bow with a HEAVIER PHYSICAL MASS will be more forgiving (easier to steady on target - more stable). And it is generally believed that bows with NEUTRAL OR DEFLEXED RISERS are more forgiving. It is also generally believed that bows with NARROW GRIPS are more forgiving, as it is more difficult to torque (twist) a slim throated grip. So what does all that mean? Maybe nothing. Last year's IBO World Championship was won by Eric Grippa, shooting a PSE Omen Pro with a 33-5/8" A2A and a 5.5" brace height - a twitchy speed bow that nobody would EVER call forgiving.


We hope you'll keep the illusive forgiveness issue in some perspective. It's more of a feel good word than a shoot good word. If you want to shoot with any degree of repeatability and precision - you have to practice. Good technique and a solid practice regimen are critical to success in the field, regardless of which bow you ultimately choose. But the less forgiving your bow is, the more exacting your technique will need to be (there - we said it). But don't make more of this issue than need be. Within a typical 35 yard bowhunting range, virtually any properly-tuned compound bow can be shot with acceptable accuracy. And with a little practice, even a novice shooter can easily bring down big game within this range. So if you hunt in dense woods where 20 and 30 yards shots are common, your bow's forgiveness isn't really a factor. Of course, if you hunt open country, where you must be able to reach out to 50, 60, even 70+ yards, where the smallest glitch means a wound or a miss, we suggest you try a bow that has up to 27% more forgiveness.

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Incidentally, this guide is the most commonly downloaded document on our website (aside from the home page). It is also the most commonly plagiarized document on our website. Back in 2002, we seeded the Compound Bow Selection Guide with a nonsense word, "hyperpolyresin." That nonsense word has been part of the text for over a decade. We just made the word up - because it sounded like something technical (an excitable plastic adhesive perhaps). Anyway, that nonsense word was deliberately used so that we could track plagiarism. If you Google the term "hyperpolyresin," you will find a number of other websites have copied and reposted our Compound Bow Selection Guide (some with our permission - most without). Very naughty. In this update, we've added a few new words. back to bows ...