PEACE IN THE VALLEY
THE AWKWARD JERK: Since we have mentioned it several times, we should briefly discuss the concept of "valley." The valley isn't part of your bow's specifications. It's part of your cam geometry and it's something you will feel when you're at full draw. When you are at full draw - at maximum let-off - you are only holding back 20-25% of your bow's peak weight. As long as you keep the bow drawn all the way back, you can remain at that full draw position as long as you like. But if you begin to creep forward a little, like you're starting to let the bow back down, your holding weight may suddenly spike dramatically. When this happens, you naturally jerk back on the string to correct it - but that jerk is pretty startling (not to mention it's an uncool move to make in front of your buddies). Now ... the idea of a "valley" is simply how much cushion you have at full draw - how far you can creep forward before the bow tries to suck you back through your Whisker Biscuit.
FORGIVENESS FOR CREEPERS: This illustration isn't exactly accurate, but you'll get the point. The "V" shape formed between the two halves of the graph is the cam's "valley," which represents how quickly the bow transitions to and from full let-off. A bow with a narrow valley is quick to "jerk forward" if you relax too much at full draw. On the other hand, a wide valley bow allows a little more leeway for shooters who tend to creep (a common shooting-form flaw). Aggressive hard cams tend to have more narrow valleys (chopping the valley builds a little more speed) and soft to moderate cam profiles generally have wider valleys.
UPDATE YOUR TECHNIQUE: If you're accustom to an older soft cycle bow, an aggressive narrow valley cycle may be a little nerve-racking at first. Very aggressive cams can have valleys that are less than 1/4" wide at full draw. This can cause creepers to jerk and flail around like a big Goober. We've actually had bows returned to us because shooters could not acclimate to a narrow valley. If you're a creeper, and you don't hold your bow firmly against the stops at full draw, be prepared to make some changes in your shooting form if you elect to go with an aggressive cam bow.
SOMETHING YOU WILL NEVER - EVER - DO TO YOUR BOW
CAUTION: This is a good time to mention a safety tip. If you draw a high let-off bow without an arrow on the string ... wait, let's rephrase that ... NEVER DRAW YOUR BOW WITHOUT AN ARROW PROPERLY NOCKED ON THE STRING. If you draw your bow back with fingers and start to relax, you're likely to forget that the full 70 lbs is waiting for you, just a fraction of an inch away. When you begin to let the bow down, your grip is too relaxed, and WHACK! A DRY-FIRE! Dry firing a bow is not only dangerous to the shooter and bystanders, but it is an ideal way to seriously damage your expensive compound bow and it generally voids your warranty. So don't do it. Don't draw your bow back with your fingers. Always nock an arrow and use your release.
DRY FIRE AND DENY: We don't want you to EVER dry-fire your bow. You won't like it. Your archery shop won't even like it. For the record, dry-fires cause a lot of conflict in archery stores (sore subject). Dry-fires precipitate a special kind of incident we call a D&D (dry-fire and deny). At least a few times a year, someone dry-fires their bow, then returns the bow to the store and swears upon the Father, the Son, and the Holy Spirit that their bow "just blew up" (though the damage pattern clearly indicates a dry-fire). This, as you might imagine, puts us in a very awkward spot. You've surely heard the phrase, "The customer is always right?" Well, let's just say that it's better for everyone if we simply don't dry-fire our bows. So ... all together now, NEVER DRAW YOUR BOW WITHOUT AN ARROW PROPERLY NOCKED ON THE STRING. Moving on.
MECHANICAL RELAXATION: Let-off is the amount of mechanical relaxation your bow achieves at full-draw (as a percentage of the peak draw weight). In contrast to the traditional bow, the draw weight of the compound bow decreases at the end of the drawstroke. This is known as Let-Off. Some bows may come with a choice of high or low let-off options. Remember, a higher let-off percentage means less holding weight at full draw - allowing you more time to aim and shoot without straining. A lower let-off percentage requires more holding weight at full draw.
75-80% IS NOW STANDARD: If you are unsure about which one would be best for you, here are a few things you should consider.
The average archer will find the mid to high let-off bow to be more comfortable to shoot, and the high let-off option is the popular choice on most new bows. Market trends have changed over the last ten years. High let-off is the standard for bowhunters (though not nearly as popular for target shooters). A good portion of new bow designs don't even offer a low let-off option any more.
BACK TENSION SHOOTERS: However, if a low let-off option is available - there are some benefits you might consider. To begin, a bow set for 65% let-off will generally shoot a few fps faster than a bow set for 80% let-off. Also, maintaining some level of resistance at full draw is necessary to keep things in good natural alignment. It is for this reason that serious competition archers and others who utilize the "back tension" release method, still prefer the 65% let-off bow.
Bowhunters generally prefer caliper releases and shooting from the valley (though not always). Still, high let-off bows are decidedly more comfortable to shoot, and they command the lion's share of today's new bow market. We get very few requests for low let-off bows today.
POPE & YOUNG: Aside from the slight differences in feel and performance, some shooters (used to) select the low let-off option in response to the Pope & Young rule. Pope & Young Club no longer disallows entries of animals record animals taken with high let-off bows, but an asterisk "*" will be placed beside the hunter's name, indicating the animal was taken with a high let-off bow. If you want your listing to be asterisk free, choose a bow with a low let-off option.
STATE & LOCAL REGS: Check your local and state regulations regarding high let-off bows. Some states have disallowed high let-off bows for big game hunting in the past. But in response to the popularity of the high let-off bow, most (if not all) states have now relaxed or dropped those restrictions. If in doubt, please check your current state hunting publications to be sure your your new equipment will be in compliance with your state's regulations. Rules and regs can and do change.
A bow's BRACE HEIGHT is simply the distance from the string to the pivot point of the bow's grip. You can think of brace height as how close the string will be to your hand (on the hand holding the bow) when the bow is at rest. The closer the string is to your hand, the more work you have to do to get the bow drawn back, since you're starting off farther away from full draw. Of course, pulling a longer powerstroke usually means more speed and power. As a general rule, shorter brace heights yield faster speeds. Taller brace heights tend to yield slower speeds.
TRADE-OFF: As with many things in archery, there's a trade-off to consider here. Short brace height bows are generally less forgiving and require more skill to shoot accurately. Taller brace heights have the opposite effect, limiting the effects of form glitches. So if you're a skilled shooter, you'll probably have little trouble managing an aggressive 6" brace height bow. If you're just learning or have mediocre skills, a little taller brace height will yield better accuracy in most shooting situations.
THE MAGIC NUMBER 7: The average new compound bow has a brace height of approximately 7", but strangely, that's an understatement. More specifically stated, literally half of the new compound bows on the market have EXACTLY a 7" brace height - and it's not by accident. It's a response to a rather peculiar market trend, and it only happened over the last five years or so. We use to see a big variety of brace heights, smattered from 5.5" up to about 9.0", in all sorts of random fractional increments (6-3/8", 7-1/4", 5-7/8", 8-1/8", etc.), but not any more. The good majority of the bows on the market seem to be specifically designed to be 7" (or 6") brace height bows. Brace height has been a very hot topic over the last five years. Bow buyers have debated this topic down to the nub. Of course, there are always outliers in every opinion study, but the overwhelming opinion of the consortium is that 7" is the magic brace height measurement. And it's practically a hard minimum. A bow with a 6-7/8" brace height is virtually a lame duck - even if the bow is fabulous. Current market perception is that a brace height of 7" offers the perfect blend of speed and good shooting manners. Anything slightly under 7" isn't acceptable, and anything much over 7" is considered a compromise on speed. Bizarre.
THAT'S COMPLETELY RIDICULOUS: Of course, we submit, with all due respect, that such an arbitrary number is absurd. We're aware of no mathematical calculation whereby the 7" brace height yields some magical bow performance apogee. Why wouldn't such perfection occur at 6-15/16" or 7-3/64"? Why 7" on the dot? The answer is ... simplicity. Seven is nice number - a lucky number perhaps - tidy and neat. And since customers have the perception that 7" is better than 6-3/4" or 7-1/16", manufacturers just give you what you want. That's why the bow market it littered with 7" brace height bows. Manufacturers don't want to miss a sale because a customer thinks their brace height specs seem too short or tall. If it's 7" they want, it's 7" they get.
UNLESS THEY WANT TO GO REALLY FAST: The only problem with 7" brace height bows is that you really can't push them much over 340 fps. To get into that truly smokin'-hot speed bow class of 350 fps bows, you need that extra inch of powerstroke. So the market has similarly embraced the 6" brace height bow. It's not like 6" brace heights haven't been around before, but we give PSE the modern era credit for popping the 6" cherry with their original X-Force in 2007. The original 348 fps X-Force was a fabulous speed bow - arguably the best speed bow we had ever seen. It had a 6" brace height and PSE made no apologies for it. Customers gawked at it, "A flagship bow with a 6" brace height? What is PSE thinking?" But the X-Force was a phenomenon - a huge hit by any measure. Few customers seemed to notice or care about the missing inch of brace height. The X-Force was awesome. The next season, other manufacturers joined in the hunt with their own 6" brace height bows. The season after that, a few manufacturers even dipped into the 5's (that might be going a little too far). So today, there is wide market acceptance for 6" brace height bows ... as long as they're really fast.
BRACE HEIGHT BARGAIN HUNTING: Strangely enough, the arbitrary 6"/7" brace height trends may offer smart shoppers a bargain hunting strategy. There are a number of bows on the market that are in statistical purgatory - presumably from manufacturers who didn't get the memo - with brace heights just under 7" or brace heights languishing in the mid 7's. Oddly enough, these bows are proverbial market bastards and are often undervalued. You may find some of them at an excellent buy - if for no other reason than market trends have left them stranded.
SHORT DRAW BOWS: If you're shopping for a youth or ladies model, don't get to hung-up on brace height. Shorter draw lengths are less susceptible to the forgiveness penalties associated with short brace heights. Shorter draw lengths mean shorter powerstrokes, so the arrow is in contact with the string for a shorter distance - negating the benefit of the taller brace height. However, the shorter brace heights are particularly beneficial on youth and ladies models for performance reasons, since they allow extra powerstroke to make up for decreased peak weights and shorter draw lengths. Youth and ladies models with short brace heights down to 6" (or even a little less) are not a concern.