Using both Aluminum and Stainless bars on a rack?

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Using both Aluminum and Stainless bars on a rack?

Postby ethan » Nov 29, 2005 2:39 am

I'm finally ordering my first rack after years of begging/borrowing/stealing from friends. I've settled on getting a microrack with a single hyperbar. So far that's what works the best for me, and I'll just be doing smaller drops (typically 150 feet or less).

I've mostly used the CMI short-frame with aluminum bars and I've been fairly happen with it. On most drops it's been very smooth and feels like it gives me the range of friction that I need (and more). However, at the top of some longer drops with very stiff rope, I've had to do a lot of manual bar spreading and sometimes even a bit of feeding(!), until I get my weight fully on the rope.

A friend suggested getting stainless bars instead to help me at the lip, but I'm worried that would be too much of a decrease in friction and that I might not be able to stay in control near the end or on slick ropes.

I've been contemplating splitting the difference and trying a rack with two stainless bars at the top (hyperbar and second bar) and two aluminum bars at the bottom. It seems like a great deal of friction comes from the top two bars getting jammed together as I go over a lip, and it often takes a lot of effort to get them apart. Switching those two bars to stainless would reduce the unwanted friction here, but I could still manually jam together the lower two aluminum bars to get extra friction when I needed it. Has anyone tried something like this? As a beginner I'm not sure whether I should be trying new things like this, but I thought I'd see if anyone had an opinion on this.

The other option is to get a "long frame" microrack such as the one that BMS offers. It's 10.5" instead of the standard 8.5" and recommended for "11-12mm rope or smaller cavers needing more bar spread." I don't know anyone using this one, so I'm hesitant to try this as well.

I weigh around 160 lbs and typically cave with clothing, gear and a pack weighing under 20 lbs. I'd appreciate any suggestions or comments,

Ethan
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Postby caverdoc » Nov 29, 2005 7:27 am

I recommend going with the longer BMS rack. I've been using a short frame since 1999 or earlie and love it. I'm a bit heavier than you and find that the short rack gives me the necessary versatility on everything from very stiff Highline 11mm in a 160' pit, to water-soaked 12.5mm in a Montana alpine cave down to 8mm Kevlar/spectra.
Mixing bars on the micro racks is too much work, and I'm not sure if they're interchangeable.
It's also a bad idea to "feed the micro rack" since you can easily end up with just two bars. Search this forum, there's a thread on it.
Hope this helps,
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Postby Scott McCrea » Nov 29, 2005 8:47 am

SS does provide less friction than Aluminum. I wouldn't worry about not having enough friction at the bottom of drops--as long as you have a hyperbar and are using reasonable diameter ropes. The hyperbar provides a lot of friction.

I use a regular size micro rack and am about the same size as you and carry about the same amount of stuff (usually) and I haven't had any trouble.

The thing you'll have to watch with mixing bars on a micro rack is the width of the frame. The two flavors of bars must have holes/slots that line up. But, I suspect that mixing the bars won't make that big of difference.

If the bars are able to mix and you try it, let us know what happens. I'd be interested to know.
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Postby cob » Nov 29, 2005 8:49 pm

Scott McCrea wrote:SS does provide less friction than Aluminum. I wouldn't worry about not having enough friction at the bottom of drops--as long as you have a hyperbar and are using reasonable diameter ropes. The hyperbar provides a lot of friction.

I use a regular size micro rack and am about the same size as you and carry about the same amount of stuff (usually) and I haven't had any trouble.

The thing you'll have to watch with mixing bars on a micro rack is the width of the frame. The two flavors of bars must have holes/slots that line up. But, I suspect that mixing the bars won't make that big of difference.

If the bars are able to mix and you try it, let us know what happens. I'd be interested to know.



I agree with Scott in general and especially when it comes to the hyperbar (tho I have never used a micro rack).

Scott, I have mixed bars on a regular rack and found that it works quite well. (for whatever that is worth).

tom
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BMS Long Microrack

Postby driggs » Dec 2, 2005 12:57 pm

I weigh 145lbs and tried the normal microrack for a week - I wound up feeding rope through several times, annoying at best and dangerous at worst. I swapped it for the long microrack and have been very happy. You get the exact same amount of friction when using the hyperbar, the same amount with your bars compressed, but enough less with them completely spread out that you don't get "stuck". It has never been too little friction for me.
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Re: BMS Long Microrack

Postby ethan » Dec 15, 2005 3:43 pm

I ended up ordering the BMS long-frame microrack, which has all stainless bars. I was really tempted to go with the short frame (and I'm sure I will curse the longer one every time I try to shove it into my pack) and I'm guessing that would've worked fine, but with my lack of experience I figured I should really avoid situations where I might have to feed rope so I opted for the longer one.

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