rack wear

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Re: rack wear

Postby bcrowell » Dec 19, 2011 6:38 pm

Even just replacing one would probably do the trick. A big one as the top or second bar should work, although some of the other, non SMC bars that fit the rack might have the right tolerances to work too. I'm not sure since I have no experience with them. I basically had the same set-up as you do until I got the big bar.
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Re: rack wear

Postby Scott McCrea » Dec 19, 2011 7:05 pm

One recommendation would be to put a grooved bar in the 2nd, from the top, position. But, you already have that. The other would be to put in some spacers between 1 and 2. Just short ones, like 1/2" long, or so. Just long enough to contact the 2nd bar when the rack is loaded. The effect on the rack will be nil. But the bridge you create between 1 and 2 will keep the top bar straight(er).

I wouldn't put those big, expensive bars on, personally. The rack is probably fine. Just need to make some adjustments.
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Re: rack wear

Postby Cavernuke » Dec 19, 2011 7:09 pm

I had the same problem; put a couple of machine shaft collars on my rack where the rope was touching the frame. It also introduces a bit of "spread" between the top bar and the second bar. You can see them in the picture on the open leg of the rack.
Image
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Re: rack wear

Postby Stridergdm » Dec 19, 2011 8:38 pm

Bah, just put some teflon spray on there. It'll reduce the friction and hence the wear. That's what I'd do.







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Re: rack wear

Postby Chads93GT » Dec 19, 2011 8:56 pm

I saw LOTS of racks at bridge day and LOTS of them had stamped steel bars for the top bar, and every one of them was canted at an angle, unlike a true top bar that is round. Every time those people would take off down the rope, the rope would immediately goto the side of the frame. Looks just like yours. hOpe it helps.
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Re: rack wear

Postby Marduke » Dec 19, 2011 9:51 pm

BMS Heavy Groove Bar, problem solved.
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Re: rack wear

Postby gdstorrick » Dec 20, 2011 5:38 am

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Re: rack wear

Postby gjm6syn6 » Dec 20, 2011 4:37 pm

I ordered a couple of bms grooved bars for the top, I like the idea of using the machine shaft collars too. Bridge day, yeah I was riding with my rack canted, pretty sure that's where the obvious wear on the frame came from :) I'm really interested in these "centering rings" do you have a pic of them on a bar, or even better, a link where they might be picked up?

Thanks,
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Re: rack wear

Postby gdstorrick » Dec 21, 2011 5:59 am

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Re: rack wear

Postby gjm6syn6 » Dec 21, 2011 5:06 pm

Oh ok, looks like some more two piece shaft collars would make a good substitution for those. Thanks for all the input everyone! I'll post some updates when I get everything setup to my preference.

Thanks,
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Re: rack wear

Postby gjm6syn6 » Dec 27, 2011 2:02 pm

Ok, after some experimenting I've found what works for me. I decided to use 3/8" two piece shaft collars I picked up from grainger (10 dollars each). I found that one of these on each side of the frame below the top bar will fix the canted top bar issue by themselves. For that to work it took some fiddling with weighting the rack and adjusting the collars until they allowed very little movement of the top bar, as well as kept it level with the rack. I ordered a full set of bms tubular bars, including the heavy grooved bar, so I gave these a try without adding spacers and they worked fairly well, the grooved bar does the job of keeping the rope well centered, even though using a tubular slant bar on the top results in it being canted just like the u-bar. One thing made me uncomfortable with the bms tubular slant bar on top, when weighted, not only would it cant, but the slot would be pulled away from the frame of the rack. That way the only part of the slot in contact with the frame was the very edge. Technically this should be fine since the weighted rope would keep it from popping off, but if there were some bouncing or the like, I could see it being a problem. I tried using the spacers to cure this on the tubular bar, but couldn't get it to cooperate. Also, one gripe I have about the heavy grooved bar, the straight slot allows the the bar to fall away without resistance. I'm sure this is a safety feature to help prevent rigging backwards, but it's a real pita when packing/carrying the rack. It won't stay in place and gets caught on everything! It doesn't hurt a thing really, just annoys the crap out of me. lol

https://picasaweb.google.com/1157064741 ... directlink
I took the nice camera up the rope to demonstrate my new setup :)

So now I'm setup with a u-bar on top, spacers, bms heavy grooved 2nd, and bms tubular slants on down. I'm very pleased with how it operates, thanks a bunch for all the advice everyone!

A couple of side notes on the spacers:

Use two part 3/8" shaft collars, the solid and split are impossible to get around the top of the rack
Not really an issue for cavers, but adding spacers prevents the option of riding a double line (there's not enough room for two ropes on the rack)
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Re: rack wear

Postby fireman1904 » Dec 27, 2011 9:33 pm

Marduke wrote:BMS Heavy Groove Bar, problem solved.


See above.... worked great for me.
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