Rack bar wear question

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Rack bar wear question

Postby DStud » Jan 4, 2013 3:14 pm

I recently bought a BMS micro rack after retiring my old Petzl Stop. This is the first rack I have ever owned. Over the holidays I did lots of caving with wet and muddy rope and the top two bars are showing some wear. My question is how much wear do you generally allow before replacing bars? My biggest concern is that the worn groove on the top top bars (hyper bar and first swing bar) isn't in the center, making the groove closer to the "gate"' side of the first swing bar.
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Re: Rack bar wear question

Postby driggs » Jan 4, 2013 5:24 pm

Run 'em until there are holes in the bars, or until there's nearly holes in the bars. You can rotate bars #2 and #4, since they are interchangeable swinging bars and get the most and least wear, respectively. You can flip #3 around to wear the other side. I've heard of people hammering out the hyperbar pin to flip their top bar, but I just replace mine once it's got a hole in it.

Brian Masney presented this rack for Bridge Day gear inspection and got a pretty good :yikes: from the safety officer.

Image
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Re: Rack bar wear question

Postby Chads93GT » Jan 4, 2013 10:13 pm

Lmao. Nice photo. What he said. When there are holes then its time to replace. I wish someone would give me a rack like hat at bridge day next year. I'd confiscate it for a souviner lol.
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Re: Rack bar wear question

Postby jcg5230 » Jan 11, 2013 1:01 pm

I just had to do my first rotation of bars myself. I heard someone once tell me that it's unsafe to put the same nuts back on the ends of the frame without using something like Loctite - does anyone else use or not use something like this? They seem pretty safe to me, and I was just going to go without.
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Re: Rack bar wear question

Postby Elliott-Hellmann » Jan 16, 2013 4:18 pm

Good question, with 5 bars I used to have to feed the rope. Now even on heavy ropes I can fly. Strange thing is the bars are not showing much wear but it's sure getting faster.
Last edited by Elliott-Hellmann on Apr 7, 2014 7:32 pm, edited 1 time in total.
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Re: Rack bar wear question

Postby eyecave » Jan 18, 2013 9:45 pm

the rope bends over the rack bars and as the metal wears away there is less and less of a bend and more of a "vertical tunnel" formed by the grooves........anyone who has ever used solid aluminum bars knows that as the grooves get deeper and deeper there is less and less bend imparted to the rope threaded thru the rack, less friction is had and eventually too fast a rappel :yikes: ......hollow stainless bars become much slicker than aluminum and require less of a loss of bend to give a faster rappel......when a groove gets deep enough to see through its gonna eventually get too fast to be safe due to the "vertical tunnel" formed by the grooves...and it is a judgement call......if in doubt replac'em and make a cool necklace out of those worn out bars..... :banana: .
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Re: Rack bar wear question

Postby eyecave » Jan 18, 2013 9:51 pm

:doh: i forgot the other question you raised.......the way to get the wear groove to form in the center of the first two bars is to use an already center grooved bar as the third bar.....don't hurt to use an already center grooved bar as the fourth one to.....
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Re: Rack bar wear question

Postby eyecave » Jan 18, 2013 9:54 pm

the big bar should be the second bar, not the first.. :argue: .....another way to get even center grooves in the first bar is to get a pre-grooved big bar........ :tonguecheek:
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Re: Rack bar wear question

Postby Jeff Bartlett » Jan 23, 2013 2:58 pm

eyecave wrote::doh: i forgot the other question you raised.......the way to get the wear groove to form in the center of the first two bars is to use an already center grooved bar as the third bar.....don't hurt to use an already center grooved bar as the fourth one to.....


I don't believe those exist for micro-racks. This thread is about micro-racks.
"Although it pains me to say it, in this case Jeff is right. Plan accordingly." --Andy Armstrong
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Re: Rack bar wear question

Postby eyecave » Jan 23, 2013 10:04 pm

dang.........those don't have four bars!........my goodness.....if the third bar don't exist......then they are rappeling on two bars..........this explains the loss of control.......

if what you meant to copy was the training bar.....substitute a pre-grooved bar for that.....that would work....
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Re: Rack bar wear question

Postby NZcaver » Jan 23, 2013 10:31 pm

I think Jeff meant there are no commercial pre-grooved bars which fit BMS micro racks.
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Re: Rack bar wear question

Postby Jeff Bartlett » Jan 23, 2013 10:48 pm

NZcaver wrote:I think Jeff meant there are no commercial pre-grooved bars which fit BMS micro racks.

Yes, what Jansen said.

Oh, and back to the OP, Riggs answers it better than I can. But he's right. Ride 'em until they develop a tiny hole, then swap in a replacement bar. Should take a good long while to wear through -- and if it doesn't, more power to you for either caving all the time or just caving in really hard conditions.
"Although it pains me to say it, in this case Jeff is right. Plan accordingly." --Andy Armstrong
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Re: Rack bar wear question

Postby eyecave » Jan 24, 2013 12:04 am

we have pointed out a need!!.......centergroovedbars4micro's.......
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