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PostPosted: Fri Mar 30, 2012 10:45 am 
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Joined: Mon Feb 07, 2011 1:14 am
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Location: Kuranda DH circa 1991
Trek 9000. Best suspension design ever,period. just do it.


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PostPosted: Fri Mar 30, 2012 11:17 am 
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Joined: Sun Mar 27, 2011 2:47 am
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Location: Cleethorpes
The Trek 9000
Image
is one design that I've always looks like one that would break easier, it doesn't look like there's enough strength in the stays. Not that I've read about them breaking, but I've also always liked it. Only thing I don't like is that there isn't much space in the triangle for a shock.

I have just updated my model. This is what I've come up with.
Image
Image

I've made the driveside thicker, it has 15mm diameter and is 'squashed' which should give it more lateral strength, without too much weight being added.

I've downloaded a demo of linkage and I'll play around with it to try and work it out. :lol:


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PostPosted: Fri Mar 30, 2012 12:18 pm 
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They look like extremely long chainstays. I think you're going to struggle to make it stiff enough also. You've got a slight falling rate going on also, but that may well be deliberate :)

Quote:
When the Specialized patent over the four-bar or Horst link design lapsed, he expected more companies to adopt it - it's a convenient way to prevent the single-pivot arc problem of shortening the wheelbase as the suspension compresses. The shape the rear axle describes as it moves through its travel is important.


The bike in your picture is a single pivot in terms of axle path.


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PostPosted: Fri Mar 30, 2012 1:31 pm 
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Location: Cleethorpes
I've shortened the chainstays, but I can't find the original geometry so it's not quite right. Started working pivots too.
Image
Image
This will have a bolt holding it together, the same as the Whyte pivots.


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PostPosted: Fri Mar 30, 2012 1:42 pm 
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Joined: Fri Nov 03, 2006 12:28 am
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Location: italy
Your design looks ace, but more suited for a cross country bike in the 80-100 mm travel range


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PostPosted: Fri Mar 30, 2012 1:50 pm 
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Location: Cleethorpes
I mean't 120mm travel, not 150mm :lol: and it is an XC design. I've got drawings of a DH design but I haven't started working on that yet.


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PostPosted: Fri Mar 30, 2012 6:39 pm 
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Joined: Mon Mar 28, 2011 9:29 pm
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Location: Somerset
With your rear pivot where it is, pedal induced bob will be present, this is why the single marins were very good with the pivot inline with the chain when in the middle ring.



KISS Keep It Simple Stupid


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PostPosted: Fri Mar 30, 2012 6:54 pm 
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merckx wrote:
Trek 9000. Best suspension design ever,period. just do it.


Your joking right? This bike generally comes top of the list for worst ever suspension design.


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PostPosted: Fri Mar 30, 2012 11:53 pm 
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Location: Cleethorpes
I always considered pedal bob to be fixed by a better shock. I also read about the Klein Mantra eliminates this, so I'm trying to think of a way to incorporate it.


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PostPosted: Sat Mar 31, 2012 6:40 am 
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Joined: Sat Oct 16, 2010 7:29 am
Posts: 36
Location: California
I'm not an engineer, but I think the chainstays will need to be beefed up. Also, I think there will be too much leverage on the upper seatstay pivot. Maybe make the pivot in-line with the stanchion clamp, and move the pivot out closer to the stanchion to reduce the torsional load on the pivot... something like this (just a quickie to communicate the concept):


Attachments:
pivot.jpg
pivot.jpg [ 30.18 KiB | Viewed 589 times ]
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