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Old 01-29-08, 07:15 PM   #1
Thumpic 
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Old Proflex......a few ????

I am re-working a mid 90s Pro-flex 853. I have no experience with a swing arm; how limber should it be? I am assuming it just pivots on a bushing over an axle and there aren't any bearings. I don't wanna get in over my head. It seems pretty stiff, but I can't imagine that it would move more than and eight of a turn at most......

I have read all the poop on the elastomer's and am hunting up replacement springs. So far I found a good one in a junk office chair. And I have a line on an identical one. I know these are not MTB springs, but I don't need a $100 titanium spring.....is there a "hidden" spring danger? Other than catastrophic failure??

Thanks.........
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Old 01-29-08, 10:01 PM   #2
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um, I haven't ever thought to try one. Does it sit in the screw end okay? The spring should be pretty stiff, because, unlike a chair, you're gonna be whacking it with yer butt at 20+ MPH. Well, at least I don't do that with my office chair...might be cool, though. Office chair slalom racing. hmmm.
When you dial the spring tension tighter, you are actually increasing the pre-load, and causing the spring (and thus the bike) to have less rear travel. It makes the bike feel stiffer, but doesn't change the actual spring rate. lessee...the spring will start to travel later in the bump, but it will go through its travel exactly as fast as it would with no pre-load. You slow the travel of the spring down by buying a stiffer spring, with a bigger number...and you'll more than likely want a slower spring than a faster one.

No, you probably don't want a titanium spring, although they really do impress the women at the starting line. But, well, I dunno. Try it. If it feels mushy and bottoms out a lot, you are probably going to have to hunt for a used one on eBay or something.
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Old 01-29-08, 10:09 PM   #3
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Oh, hey...don't go hucking any giant drops until you know it is gonna work. Test it on yer curb, okay?

Matter of fact, you probably shouldn't huck a proflex at all...
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Old 01-29-08, 10:44 PM   #4
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I huck my office chair from time to time and it holds up pretty well
edit: check out risse racing they always had funky spring sizes. is the shock a noleen?
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Old 01-30-08, 07:59 AM   #5
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Heres a little info that I dont agree with totally (only because I own a ProFlex 4500) but Ill post it anyways
http://archive.mtbr.com/12/0EE92120.php
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Old 01-30-08, 08:51 AM   #6
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Springs are rated by the weight they support. Get the right spring. This might give you some ideas...
http://www.rapiddescentscotland.co.u..._position=17:7
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Old 01-30-08, 10:17 AM   #7
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I don't "huck".....do I?? If that means going off a curb and screaming "WWEEEEEEEEE!"...then maybe I do.... I am not a downhill racer or anything........there IS a looong hill down to the bar though........

There is no shock, just a spring replacing the elastomers.......

What about the frame pivot??

And Rapid Descent can definitely hook me up; but I'm not spending that kinda dough...........
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