Bowsite.com

We shot a detailed video review of the pack a couple weeks ago, and I wanted to post it here and get your guys' thoughts on the pack. Would you pay $699 for a pack like this? I know $900 bows have become the norm, but do you have a limit on packs?

Give us some feedback... :-)

Many thanks, Corey Jacobsen Elk101.com - Extreme Elk Magazine

P.S., Bowsiters save 10% on all orders at Elk101.com....use code 'BOWSITE10'.

Tenzing tested it with 400 lbs loaded on it, and had no issues with the shoulder straps, frame, or any other part of the pack. It's light and tough and truly made to go in light and come out loaded down.

Tenzing packs are made by Plano. They've been around a long time.

Am I correct that with wings and bottom compartment we are looking at a 4000 ci pack?

You are running with the big dogs for price. IE Kifaru and MR. That is a tough high end market.

How durable is it? Any zipper issues?

Rick M

It's really tough to even put a number on capacity for this pack. You can configure the pack with the 3200 ci inner gear bag attached to the outside and easily fit 2 elk quarters (or more gear) against the frame, plus still have the side wings, lower compartments, and lid. There are a couple shots similar to that configuration in the video, and my guess is the pack would be closer to 7500-8000 ci.

The packs are incredibly durable and quiet....and I haven't had any issues at all with the zippers.

The real benefit of the CF13 is having a 5 lb pack with the capability of hauling out more weight than any of us can physically carry. I love the idea of being able to hunt in a 5 pound pack, and know I can haul out a bunch of meat on the first trip. There are definitely other packs that will haul a lot of weight, but none are in the 5 pound range.

For those who have ordered today, the packs will ship out this afternoon and we'd love to have you give us your feedback once you get the pack and have a chance to load it up. Thanks!

Thanks, it was hard to get a grip on the actual volume. The numbers look good. It will be interestig to see some reviews from in the field.

Don't suppose you want me to test out a demo for you this fall:)

Rick M

There are probably some people on earth who could carry out an entire boned elk with this pack...

I have packs in the 6 pound range that will carry everything I can very comfortably because they adjust, with lifetime warranty's, well constructed, well thought out, tough, and flat get it done for way, way, WAY less than that. 2 pounds. That's a bottle of water.

It sure looks nice and is great at what it does no doubt. If it is what you need to get it done than sobeit. I'm just thankful I don't share those sentiments. And quite frankly, that goes for any $600 pack. What are you truly paying for when you buy it? No doubt a great pack but, what does it do that you can, that others won't comparably. In my eyes it is purely marketing.

You or anyone else want to impress a new product that changes the way we hunt, design one that weighs a pound, can compress and get air to our backs when hunting, can carry 120 pounds comfortably when coming out. That I would pay $600 plus for. That would be state of the art, or game changing as the review states. To each his own. No disrespect meant, just don't get the notion driving this kind of price for something that basically already exists much, much, MUCH cheaper. God Bless

these are load lifters

no doubt some will love it, but for comfort, why spend so much if you have a longer torso when this is a substantial downfall in backpack fit for hauling weight?

http://www.archerytalk.com/vb/showthread.php?t=1926915

Amoebus: heres two links to popular elk hunting forums where they discuss load lifters on the CF13

This question should probably be opened in a new thread, but I think it's related to this pack so I'll ask it. Can you (or anyone else) explain to me what the benefit is of having the load lifters at a 30-45 degree angle? Or, what the downside is of having them at a reduced angle? I have used both, and I'm also a mechanical engineer, so angles and equations involving mass are interesting to me for sure (that's the nerd side of me). In your explanation, what is the purpose of the load lifter, and how does having it at a 30-40 degree angle better accomplish that purpose?

Many thanks, Corey

Wouldn't a load lifter at a 45 degree angle simply shift the contact point and force load to a different location (front of shoulder, rather than top or back of shoulder)? This shift would definitely translate to a percentage of the load being shifted onto the hips (depending on the contact location, not load lifter angle), and make the weight bearing on the shoulders more comfortable. This is true IF the belt was rigid at the contact points to transfer the weight straight to the belt (waist) AND if the contact point from the load lifter to the shoulder strap didn't change.

Wouldn't moving the contact point up onto the front of the shoulder also serve to shift the force load/angle to the front of the shoulders? I completely agree that a negative load lifter angle would be bad and would make it impossible to transfer the point load, but adjusting the contact point on the shoulder seems like it could transfer load angles as much as the angle of the load lifter itself, right?

Mistake a line from your peck muscle and take italong yourskin and back behind your back,what angle do you need to move weight/pressure off your shoulder?

I understand you gave packs to sell but you'll never convice anyone that has used functional loadlifters that they are not needed and if you have never used them you truelly will notknow how comfortable a pack can be.

Mistake a line from your peck muscle and take italong yourskin and back behind your back,what angle do you need to move weight/pressure off your shoulder?

I understand you gave packs to sell but you'll never convice anyone that has used functional loadlifters that they are not needed and if you have never used them you truelly will notknow how comfortable a pack can be.

It would seem that the vertical component of the force is influenced by the location of the attachment (front of shoulder) as much as it is by the angle of the load lifter (until the load lifter goes negative). If that attachment point doesn't change and the angle up to the frame is adjusted, what is the actual calculated difference in load on that point as the angle changes? As long as the load lifter doesn't contact the top of the shoulder and that contact point remains the only point load, it seems that it would be very minimal in comparison to the weight of the pack and the original vertical component of the load.

I would use a construction crane as an analogy. When it picks up a generator, the weight transfers to the crane. If the crane is picking up your shoulder straps and is sitting on the top edge of your pack frame, the load transfers to the pack. Granted, the crane will pick up 100% of the load where our lifters won't because of design, but the weight transfer principals are the same.

I think for some of us, lifters are over rated because with a good load in the pack, it's only a matter of time and the whole shebang will slide down and we'll be back to a fairly even load on both our hips and shoulders.

Can't say I can explain the math of it, but I have tried a ton of backpacks, and good suspensions with functional load lifters consistently wins in the comfort department.

Even compared to the "old technology" (said with humor)of an aluminum stay Kifaru Timberline 1 (7200ci actual size) you only gain 5oz weight savings yet still have the ability to get correct/comfortable fit and function....and its about $60 less.

If you have a "normal" back profile you can get even lighter options with correct fit from Kifaru and Stone Glacier for less cost.

Many thanks, Corey

I'll try and explain the concept of a load lifter.....

When used correctly, the load lifters should be transferring at least 65% of the weight to your hips, but for this to happen, the actual lifter will need to be above the shoulder.

Why does it matter what the angle is?

If you start out with a 15 degree angle, and 25lbs in the pack, by the time you have 85-100, that angle will be ZERO. That is because the pack/frame is going to sag.....not an arguable point, just the facts of heavy load hauling. So the best option (for potential heavy hauling) is going to be a 30-45 degree lift from the start. This is why most people will prefer a taller pack frame.

Why not go 20"s above your head with a frame?

That's an easy questions to answer and comparable to taking a 18 wheeler to the drive through! It can be done, but makes no sense.

You will actually go into the negatives after a 45 degree angle, so there's a point you go to far, but again, if you focus on the 30-45 degree range, you'll be good to go in any situation.

Does a load lifter actually lift my pack up?

The lifter ONLY lifts the shoulder straps off of you shoulder.....NOT THE PACK WEIGHT OFF THE GROUND! Again, this is why the angle is important.

What are the down sides to a taller frame?

The biggest, and really the only, is the frame being above your shoulders. So if you're hunting in thick brush/dead fall, you will need to be mindful of a taller frame. I live in Colorado, so that's a non-issue for me. This may be a completely different story for someone else, so you'll need to decide what works best for your style.

What happens when my lifters are at a negative angle?

Well, they become load stabilizers and keep the pack from shifting, but will not transfer any weight to the hips. So your shoulders will be packing the majority of the weight.

Load lifters are not a new thing and have been used by mountaineering backpack companies for a long time. If you google "load lifter", you can find videos and info that will explain everything very clearly.

Good luck to everyone this season....no matter what pack you're using!

Aron its great to see you on bowsite again. Thanks for the explanation.

Corey i hope i didn't push any buttons or anything. I have the utmost respect and adoration for you, your family, and your company. it was just my honest opinion about a pack i have not seen or touched in person.

i think many hunting pack companies would benefit greatly if they designed "modularity" into not only the pack volume but also in frame rigidity and heigth. beyond volume, heigth and stiffness are the biggest differences between load haulers and daypacks. i think a removable hipbelt (that can traded for a lighter one) and a removable frame extension designed for load lifter placement and extra lashing (similar to Mystery Ranch's frame jacker)should become the norm for "modular hunting packs." this would allow the user to have a compressed volume daypack that is both short and light wearing for movement off trail. once extra volume and load bearing are required, the pack opens up, the extension raises the lifters and the mumbo jumbo belt comes out. its two extra things to carry inside the pack but is a hell of a lot better than two packs or one that meets neither needs well but both sufficiently. thoughts?

If you buy a new Tenzing CF13 you can send it to me and I'll add some functional load lifters to it for ya ;^)

OK, Aron clarified one of my arguments very clearly. The load lifters do not lift the load in the y-axis. They are simply meant to lift the shoulder straps off the top of your shoulders so the weight of the pack is transferred to your hips.

There are 2 forces associated with lifting a pack. Number 1 is the weight of the pack. If a 100# weight were 1" thick all the way up your back, this would be the only real associated force...a 100# force pulling straight down on your waist belt with your hips taking in 100% of the weight. Shoulder straps wouldn't be necessary but could be used to transfer some of that vertical force (weight) to your shoulders if they were connected below the shoulder. If they were connected horizontally, they would serve no purpose.

However, getting 100# so it sits flush with your back is impossible. It sticks out some distance from your back, resulting in a moment arm at the point where the pack and the waist belt connect. The moment arm is calculated by the distance the center of the weight is from your back, multiplied by the weight of the pack (mass). If the center of the weight is 6" off your back, the resultant moment arm is 50 ft*lbs at the waist connection point. That moment arm transfers a horizontal force component to the top of the pack. The horizontal force component is directly related to the height of the pack (or the distance from the connection point at the waist to the connection point at the top of the pack). A taller pack will result in less horizontal force needed to counter the effects of the moment (i.e. core muscles). For example, a 24" pack will need 25 lbs of horizontal force at the point of contact on the front of the shoulder to keep you upright. A 30" pack will only require 20 lbs of horizontal force exerted. Coincidentally, moving the center of the weight in your pack 1.2" closer to your back will have the exact same effect as having a 6" taller pack (reduced horizontal forces).

Neither pack will change the vertical component of the force, though(assuming the shoulder straps are held up off your shoulders causing the strap to contact the front point of your shoulder). A taller pack will reduce the stress on your core muscles that are being used to keep you standing upright, but the initial 100# weight will still be 100% on your hips. The shoulder strap's sole purpose is to allow you to pull into the horizontal force caused by the moment arm. Again, this is in the perfect world.

In the perfect world, the angle of the load lifter has no effect on the resultant horizontal or vertical forces. In fact, it is not needed. A load lifter at a 10 degree angle will not change any of the forces, and neither will one at a 45 degree angle. However, we all know this isn't realistic. Once you put 100# in the pack, it's going to "settle" and slide down your hips, transferring vertical forces to your shoulders. Additionally, it is nearly impossible to get a shoulder strap to contact the front point of your shoulder without transferring a portion of the load elsewhere along the way.

Load lifters need to be at an angle so when settling occurs, you are still at a positive angle and able to keep the vertical load off your shoulders. The more the waist belt slips, the more angle you need on your load lifters. A higher angle will also bring the contact point further out to the point of your shoulder, allowing you to utilize your core muscles to assert a horizontal force and your hips to take the vertical forces. However, the change in angle will only change the horizontal forces by 1-2 lbs with a 100# pack on.

Now, all of this is under an ideal situation where you are able to carry 100% of the weight on your hips. This may be possible for some, but the muscular and skeletal wear will usually cause failure sooner than later for most of us. Therefore, shoulder straps are used to carry a portion of the vertical load, as well as the horizontal load caused by the moment arm, and transfer some of those forces to our upper body muscular and skeletal frame. There is no set percentage of what is best...everyone is built differently....some are able to utilize more of their core muscles, some have stronger delts, traps, or pecs, and some are able to carry more of the load on their lower body frame. Finding that perfect balance is an individual preference and for some it may be a pack that holds the weight closer to your back. For others, it may be a taller pack that reduces the horizontal forces on the front of the shoulders. For others, it may be carrying more of the vertical forces on the shoulders.

In the end, a "functional" load lifter would be described as one that reduces the amount of contact and the vertical forces of the shoulder strap, regardless of the angle. As long as the LL is able to lift the shoulder strap any distance off your shoulders AND keep the contact point on the front of the shoulders, it will do the same job. If the pack also has a waist belt that doesn't slip, that will greatly add to the comfort and performance of the pack, and allow the pack to get away with a much lower angle on the LL's before they start to contact the top of the shoulders.

For some packs, a 45 degree load lifter is most comfortable. But in no way does that mean another pack needs to have a 45 degree load lifter to be equally as comfortable.

Agree or disagree?

Many thanks, Corey

The Tenzing should be a good pack and if the belt is tight enough, loosening the shoulder straps a little bit provides some relief, although the load will pull away from the body slightly as a result.

In no way am I saying everyone needs to sell their Pack B and buy Pack A for reason X. Rather, I'm hoping I can shed some light on the mechanics of some of the features everyone says they like, but can't explain WHY they like them so much... :-)

Thanks everyone!

Corey

Rick M

how do you feel the waist belt performs on the CF13 for pure load bearing performance?

what is your torso length and relative load lifter angle with this pack?

and with a 19.5 inch torso?

The waist belt on the CF13 is one of the best I've worn for bearing the vertical load. It wasn't that way initially, but as I was testing it out, we took the belt off and made some other adjustments. When we re-attached the belt, we did it upside down (on accident). However, when I strapped the pack back on (with 120 lbs), the waist belt was rock solid and there was no slippage. We left it that way... :-)

My torso length, as measured from the top of my hip bone to the top of my shoulder is 19" (I'm 6'0" and 180lbs).

I'll attach a series of photos showing the pack and load lifters with 70.8 lbs in it.

Here is the pack with the shoulder straps loosened and all the weight bearing down on my hips.

I have to agree with others, those of us that require the load lifters have used plenty of other packs that don't have them. I will not even consider a pack without them and a great belt combo but that is just me.

People still post up how great the Eberlestock X2 is for packing out elk and that nothing is comfortable with 100lbs, well there really is no understanding until you have first hand experience. So if you have never had functional load lifters and are ok with your shoulders taking abuse then I can see why a lot of guys don't see the need to spend $600 on a pack but the guys willing to spend $600 plus on a pack usually require this or such as the MR goes proven long-term durability, tenzings first year out was rough with faliures of stitching and zippers and to come out with a $700 pack their second year can make us think twice and then overlook the pack altogether when we see key items we personally would require.

Not trying to be rude just stating why I would give it a pass.

Maybe some durability video could be shot, do what was done with the Kifaru and SG packs. Put 70lbs in it and throw it off a mountain and then prove that the frame has held up. I think that could help prove that the frame is in the same league as Kifaru and SG. If it breaks well then you can go to Tending and help them further develop it.

He stated there is over 70 lbs. in the pack in those pictures.

Again not trying to be critical but it is a $700 pack.

The waist belt works far better in the inverse position, which is how Tenzing designed it. When we were testing it, the belt was in the traditional position and we accidentally reversed it. It solved the slipping issue and was left that way for the production runs. And yes, I think the extra 3/4" of carbon above the load lifters is there to ensure there aren't failure issues in the carbon with heavy loads.

Hanst,

Having owned 3 of the 4 packs you mentioned in your post above, I can tell you that for me, the CF13 settles the least under heavy loads. I've attached a photo of me shooting my bow with 180 lbs of solid granite slab loaded in the CF13...that doesn't happen with a large vertical force component in the shoulder straps. The load lifters were at the same angle then as they are with 70 lbs in it. It will definitely settle some after hiking a mile, no doubt, but to say there is zero room to settle without pushing vertically on the shoulders is inaccurate. It does have less room to settle for sure, but in my experience, it also settles less than other comparable packs and the vertical component of force on the shoulders will not be any greater.

Again, not trying to sway anyone or make anyone feel that their pack is inferior in any way, just simply stating my opinion based upon my experiences, and offering first hand experience with this pack, rather than assumptions. I've packed out plenty of heavy loads, and the combination of features and versatility the CF13 offers puts it up there with the best packs I've used, especially under a heavy load. But like I said before, packs are like elk calls...if they don't work for you, they definitely aren't the best one for you to use.

Many thanks, Corey

Holy smokes, I'd look like a turtle laying on its back!

is there any other attachments on the bag for external mounting other than the two at the top that connect to the top lid? what is the best external configuration that yields the most secure load for the bag?

is there any way to vertically move the bottom shelf to adjust/distribute the weight vertically or is it in a fixed position at the bottom of the frame? i could see this being a MAJOR flaw if it cannot be moved up to at least the mid frame.

Yes, every single component of the pack can be adjusted in approximately 1" increments using the slotted pattern on the frame...the bottom shelf, the waist belt, the shoulder harness, etc. Also, the inner bag attaches at 6 points to the frame as well as 6 points on the exterior of the pack so it is very secure in both places. Obviously, on the exterior you aren't going to be as rigid as when you attach to the frame itself, but with a load of meat on the frame and the gear bag attached to the exterior of the pack, it is still very stable due to the 6 attachment points.

Thanks, Corey

WRT load lifters, etc. any design is going to have trade offs. The optimal angles require a taller pack. I hunt with my pack so taller is a problem, catching on brush and trees all the time, some when you are crouched over or crawling you can't even lift your head to look up in front of you. I have a 24" frame and it even gets in the way at times. A 26" would likely haul better, but for me it's not as huntable, almost unhuntable for what I do and I can deal with a slightly less comfortable hauler when the big loads come out.

They do aid in transferring a load to your hip belt. WRT slipping, some like the Kifaru have compound pulls on the belt to make it as tight as a person could possibly want. And not just the belt, lumbar pads play a great part in the system as well.

A person has to figure what purpose and tasks he wants that pack to preform. Only packing loads? What loads, your camp or meat or both? How far, how many trips? Going to hunt with it as well? Fly with it as a carry on even?

It a fun time with this new technical gear. But depends on your uses. Some folks get by with a crescent wrench and a pair of pliers and a couple screw drivers in a bag and they are fine. Others have thousands in Snap-on tools. Me..... I'll admit, I'm kind of a tool whore.... but the right tool for the right job is a pleasure to use.

Corey, I too am a mechanical engineer and the angle of the load lifter does affect the resultant vertical load on your shoulder. If the strap goes straight back from you shoulder to the load lifter, the vertical force on your should is equal to the tension in the strap. Neglecting friction, I calculate the vertical force on your shoulder to be F = T - T*sin(angle) [T=tension]. At 45 degrees the vertical force on your shoulder is about 30% of the tension. At 10 degrees, it is about 80% of the tension.

You are absolutely correct - if your waist belt isn't supporting the vertical load and it was just hanging on your shoulders, there would be a drastic difference in the experienced vertical force. With a waist belt that doesn't allow as much slippage and allows the vertical load to be transferred to your waist, your shoulders are under far less vertical forces and can focus on their primary task of keeping the pack balanced (i.e. horizontal forces). Think of hiking down the trail with a heavy load and reaching back with your hands to "lift" the bottom of the pack to give your shoulders relief. While none of us could hike for miles carrying that weight in our arms, it completely eliminates the vertical forces on our shoulders for a small moment. However, we still have to lean into the shoulder straps to balance the pack (horizontally).

A good waist belt that doesn't slip will essentially do that same thing and greatly reduce the vertical forces on your shoulder. At this point, the vertical forces on your shoulder are quite minimal (and comfortable), and the resultant load on your shoulders is not noticeably effected by the angle of the load lifter (as long as the load lifter is not contacting across your shoulder). In fact, at a steeper angle, it requires more horizontal force (core/back muscles) to balance the pack (the inverse of the same force equation you mentioned).

There is a trade-off in the angle of the load lifters and if your shoulders are carrying too much of the weight of the pack, a steeper load lifter will reduce that vertical load. If you have a good waist belt that reduces slippage and transfers that load to your lower body, a lesser load lifter angle will allow you to more easily balance the pack horizontally without compromising the vertical forces on your shoulder. The contact point of the load lifter also plays a huge role in where those forces are distributed.

Agree?

In no way am I saying a lesser angle is better than a steeper angle. What I'm pointing out is that in a well-designed pack, a load lifter does't need to be at a 45 degree angle to be "functional" and the experienced differences would be minimal to negligible. Load lifters at 45 degrees will reduce vertical forces (which are relatively small with a good pack), but at the cost of other features such as a taller frame (to achieve the angle), etc. For someone looking for a lightweight pack that sits just above the shoulders and still has the capacity and ability to haul a very heavy load quite comfortably, a 20 degree difference in load lifters should not be a final deciding factor. Conversely, for someone hiking an open trail to set up camp to hunt above timberline, a pack with steeper load lifters might be the better choice (which is why you see more "hiking" packs with steeper angled load lifters).

We are talking about the downward force on your shoulder right? If so, your analysis is wrong. In this example, I calculate a 21 lb downward force on your shoulder with a 10 degree load lifter and a 10 lb downward force on your shoulder with a 45 degree load lifter. To me, on a long pack-out, this is significant.

Do the analysis yourself or I can send it to you. In engineering terms, construct a free body diagram of the shoulder strap by itself with the tension on each end of the strap and the x & y components of the shoulder force on the strap. Sum of the forces in the x = 0, sum of the force in the y = 0. Solve for the shoulder forces: Fx = Tcos(B), Fy=T-Tsin(B). Using Fx=25lbs per your example, I get the numbers above.

With time and more independent reviews this pack may be more interesting.

It carried the load well, in my opinion.

Hang on; isn't that your own body weight?? I'd need a crane and a rescue team on standby...I know I couldn't get up again (I weigh in at a sylph-like, strippling 217 lbs...+/- a few ounces)

Whilst a pack costing many dollar (or pounds, come to think of it) isn't on my "new shiny gear I would really really like to have" (I'm saving for a new bow), I believe in the old adage "you get what you pay for", and like nearly everything...quality ain't cheap.

Question for Aron/TheElkReaper: in your "Head to Head" column in Extreme Elk, you have a rating for "Bet your Life on it" [apologies in advance if that's not 100% accurate],in terms of just how nails-tough a pack is. Where does the CF13 figure?

Many thanks

As always, Good Luck and Good Hunting

Kenneth (A British Bowhunter and Proud of It)

So the parts/pieces and buckles would be what needed further testing/abuse.