I’m in the market for a new bow, so I’ve been slowly skimming through reviews and various bits of research. Unless your are an absolute expert on archery equipment, some of this research can be kind of dense and filled with technical jargon that the every day hunter wouldn’t know. Luckily I came across a really great article on Cabela’s website that really explains a lot of the “jargon” that you need to understand when picking out the right bow. So here are a few selections from the article that I found most interesting. You can follow the link below to read the full article. Enjoy and good luck picking out your next bow!
By: Mike Schoby
“A lot has been written about cams (or wheels) over the years. The different styles, shapes and individual features are numerous, but they can be generally narrowed down to four distinct types: round wheels, soft cams, hard cams and single (solo) and the 1.5 hybrid cams. Each has it’s own set of characteristics that dictates its best application.
If you gauge the different features in terms of speed, it is easy to rank them from slowest to fastest (round wheel, soft cam, with hard cam and solo cam and the hybrid cam being very similar), but this only tells part of the story. Other factors in addition to speed are comfort, tuneability, quietness, and accuracy that make an archer choose a particular cam over another.
Round wheels, as noted above, are the slowest of all the cams, but they are still with us today for a reason; they are arguably the most accurate, as well as the most forgiving of all the cams and work extremely well for finger shooters. They are reasonably quiet, vibrate very little and are easy to tune. Their slower speed and pinpoint accuracy makes them a favorite for fixed-distance target shooters. Due to their rainbow-like trajectory, their popularity has faltered in hunting applications.
Soft cams are about the slowest cams many hunters opt for. They have many of the advantages of a round wheel, but they generate enough speed to make them adequate for many hunting applications. They are still quiet, stay tuned relatively well and are forgiving even for finger shooters.
Hard cams (or hatchet cams as they are sometimes called) are the fastest of the dual cams. While they create blistering arrow speeds, they have several major disadvantages for the hunter. First off, they are harder to keep tuned than any of the other cams, due to their propensity to stretch strings and buss cables. They can also be loud, and need to be dampened considerably. They are also the hardest to shoot accurately and the least forgiving. However, if you are an expert archer, and enjoy tuning a bow, the speed may outweigh the inconvenience of occasional tuning.
Solo cams (or single cams) are a single hard cam matched to a round idler wheel. Their popularity has been such a success that virtually every bow manufacturer today produces a solo cam bow. They are also very easy to tune since there is only one cam that rolls over. They are also extremely quiet and as fast as any dual cam on the market.
The 1.5 hybrid cams are the newest style of cam on the market. They are a combination of both a dual cam and a solo cam. The speed of the hybrid cam is similar to that of the solo and hard cam. The main advantage of the hybrid cam is that it essentially elimates nock travel, which is found on a solo cam. It functions the same as a solo cam where the idler wheel is replaced with another cam. The addition of the second cam offsets the movement of the nock as compared to a solo cam.
The ins and outs of cam let-off and adjustability
Regardless of which type of cam you decide works best for you, there are several things to pay attention to when selecting the exact model of bow/cam. Thankfully most of today’s bows are adjustable for draw length, but how adjustable they are and with what amount of difficulty are two important questions that need to be answered. It is always smart to have your draw length measured before buying a bow. If you change your shooting style or grow a bit (in the case of an adolescent) draw length adjustment becomes imperative.
Let-off is another cam function that needs to be understood to effectively tailor a bow to your needs. Let-off is expressed in a percentage and on many of today’s bows. It is adjustable between set parameters (65%-80%). For simple math, let’s assume that you have a 100-pound bow (not realistic -just simple). At peak weight, you will have to pull 100-pounds but after the cams “roll over” and fall into the let-off valley, you will be holding 35 pounds with a 65% cam; with an 80% cam, you would only be holding 20 pounds. Different states have different regulations on how much percentage of let-off is allowed for hunting. If you have a chance of encountering a trophy you should stick with 65% let-off bow. For the trophy to be eligible for its appropriate place of honor in the Pope and Young Archery record books, the maximum let-off allowed is 65%.
Speed Rating IBO vs. AMO
There has been a lot of confusion over bow speeds in recent years, as manufactures all vie for the top spots on the velocity charts. In an attempt to keep the playing fields level and give consumers a basis for comparison, two different rating methods have been adapted. IBO (International Bowhunters Organization) and AMO (Archery Trade Association formerly the Archery Manufacturers Organization) are the two standards used to compare speed. While they are standard, they do differ drastically from each other.
AMO speed is figured using a bow set up at 60 pounds of draw weight, 30 inches of draw length and using a 540-grain arrow.
IBO speed is figured using an arrow that weighs 5 grains for every 1 pound of bow weight. Example: A bow set at 70 pounds of draw weight with an arrow that weighs 350 grains (70×5).
As you can see, the rating system is drastically different for each method, which explains the wide spread in velocities between AMO and IBO speeds. IBO is using a higher draw weight, a drastically reduced arrow weight (compared to AMO) and an undisclosed draw length (longer draw lengths translates to more speed). Since many archers have a “need for speed” attitude, it is obvious why bow manufacturers choose to advertise the IBO speeds of their bows but for the best comparison AMO is a more consistent litmus test. ”
Thanks to Cabelas for the great info!