Bikini vs New Duplex Frame

[Hootsma]

I currently have a Bikini that I've been running for 2 seasons now, and really like it. However, I have experienced what most searches indicate on this forum regarding the reduction of comfort of the Bikini as you go up in weight (80+lbs). I'm trying to figure out if the loss of comfort can be reduced with a different frame or if there is just no avoiding the suck. And the reviews of the new Duplex frame have me intrigued.

I think I understand the cause of the discomfort and my question is will the new Duplex frame correct those issues. I'm not seeing it, but I was hoping someone who has used both can address my specific issues.

I'm 6' - 0" with a 19" - 20" torso and I have a 26" Bikini frame with normal back composite stays.

As I approach 100 lbs of pack weight, I lose load lifter angle to the point where the load lifter straps are completely flat which causes me to lose all ability to relieve the weight on my shoulders. I believe this is related to the geometry (or lack there of) of my backside. The pack sits where it wants to sit based on the shape of my back side and hips. The hip belt rests perfectly centered on the hip pointers, but as weight is increased, the front of the belt remains put, but the back of the belt sags and oozes down my back to the point of complete loss of load lifter angle. I can correct this issue, but there is a heavy price. I can regain some load lifter angle by lifting the frame up and cinching down really tight on the hip belt. But, this creates even more pain. This crushes my hip pointers and creates so much friction with the small of my back that it feels like I'm tearing the flesh off of my back. I can only stand this for a very short time before I have to loosen the belt to let the frame sit where it wants to sit.

This doesn't seem to be related to the way the frame of the Bikini is configured. It seems more like it has to do with the hip belt and lumbar pad and how they fit my body geometry. From what I understand, the hip belt assembly on the new Dublex is the same as the Bikini, so I would expect to have similar issues with the new frame. There is a difference in the lumbar pad between the 2, but it doesn't seem like it's enough to correct my issues. The main change in the lumbar pad is the complete coverage of it with the sticky material. I can get the Bikini lumbar pad to "stick" to my back higher than it naturally wants to sit, but with a heavy load, it's pretty painful. So, this doesn't seem like it would fix my issues.

Ideally, what I am trying to achieve is a pack configuration that allows me to hike with heavy weight where my legs are the weak link, not my shoulders and hip pointers. Does anyone think that the new Duplex frame can do this for me given my issues above? If so, can you provide any explanation of the differences between the 2 frames which will address my specific problems?

Does anyone think that flat back stays might fix my issues? I've done the test against a wall to determine stay shape. I definitely have enough curvature in the small of my back when I stand against a wall to fit my entire hand. However, that is not my posture when I'm hiking under heavy load. I'm leaning forward, slightly hunched over. When I assume this posture against a wall, that curvature space completely goes away. Does this mean that I should have flat back stays?

 

[Shrek]

You need to call Kifaru and talk to Aron. Aron knows how to get you fitted right and address issues better that anyone else. There are lumbar pad options as well that may help. If you'll let him he'll get you squared away even if it means recommending a competitor.

 

[dotman]

Simply stated, yes the new duplex should solve your problem as the belt locks into place much better. I never had an issue with my bikini but the new UL Duplex fits so much better and conforms to your back. The added grip on the lumbar pad pretty much eliminates belt slippage and the bikini belt never slipped badly on me but there is a difference.

With any Kifaru pack you need to tighten the belt until you think you'll pop, then it should stay put.

I hauled out an entire MD and gear and I know Aron has packed around 120lbs+ in the UL duplex, don't let the arrow stays fool you, I had doubts until I used them. They can handle the weight, maybe for a moose quarter I would op from a stiffer stay, but the UL duplex is more then capabile for 99% of us. The Alaskan Hunter have much different needs as far as heavy weight and distance is concerned.

 

[justinspicher]

Do you tighten the delta straps at all? You mentioned cinching down the belt, but I'm unsure if you mentioned the deltas. I've only used the old duplex and the bikini and I couldn't tell a difference between them at any weight from 40-110lbs. I just seemed to sweat more with the duplex.

A call to Kifaru is probably your best bet. You'll likely get a pelethora of different opinions on this topic.

 

[mrbillbrown]

Save yourself time, trouble, and pain and give Aron a call. He'll shoot you straight.

 

[Hootsma]

I always forget about the delta straps, so no I wasn't using them when under heavy loads.

I'm still a couple months out on an actual purchase if it comes to that, so I haven't called Kifaru yet. I thought I'd get some feed back here first. But, once I'm ready to make a final decision, I intend to call Kifaru and see what they recommend.

 

[tipsntails7]

It sounds like a pack fit problem, maybe you need flat back stays, my advice along with everyone's else on this thread is call Aron.

 

[PathFinder]

I used both this season. I experienced a bit of what you're talking about. I'm in the same boat as you; there just ain't a lot for a pack to grab on to around my waist. The lumbar pad on my Bikini didn't want to stay put, even around 50 lbs. Since then I've been using my UL frame with no problems. I've put over 50 miles on my UL frame, including about a 3 mile pack out with all my gear, my 11.5 lb gun, and an entire boned out mature muley with cape, head, and horns. Although I felt the lumbar pressure you referred to, the pack stayed put for the entire hike out. With every other pack I've used, I tend to get hot spots on my hips with loads over 50 lbs but I didn't feel that at all with the UL frame. I think that with a load that heavy the waistbelt is going to have to be tight to stay put no matter what. The tight belt and lumbar pressure are a good trade vs a pack that won't stay put IMO.

 

[WV Dan]

I wish I could offer some technical help, I can't. However I had a normal back stay bikini frame for a couple years and under normal loads it was fine with 50+ pounds (a big load for a out of shape guy like me) it got uncomfortable. I called Kifaru and they (Aron and Frank) went way beyond what I consider typical costumer service and I have flat back stays now. Big improvement, I can handle heavyish loads much better. In short I reflect what others have already advised--just call Kifaru they will set you straight.