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PostPosted: Fri Feb 07, 2014 1:59 am 
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Call me crazy, don't care...just started to dig into this idea; why not doing this modification?! I believe the only challenge here is to make sure I eliminate the pivoting movement between the shock and the Seat stay. Since there is a pivot on the bottom at the rear hub, the compression would not be an issue...I'm just looking for fun projects :beerchug:

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Posted: Fri Feb 07, 2014 1:59 am 


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PostPosted: Fri Feb 07, 2014 9:29 pm 
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Since you asked why not, I will tell you why not:

1. Loss of lateral stiffness, due to the extended unsupported length of the the stay/shock unit. There is a reason bikes of this design (http://www.bikepedia.com/quickbike/Bike ... +Ti+Amp+FS) went away! You would basically be rolling your bike back 15years, technologically speaking!

2. At a minimum, it will require a lot of labor to make some sort of custom machined fitting to connect the shock and stays in a way that has even a semblance of stiffness, so basically, a lot of labor to end up with a mediocre result.

Having said that, if you just feel like messing around and having some fun with your bike, it is worth considering the following....It is a little tough to tell from your bottom photo exactly how the the shock eyelet and end of the seatstay are configured. Having said that, I would imagine that if you really want to do this right, and as you say, eliminate movement at that eyelet, you might want to take a few ideas from current model Specialized bikes that use yokes attached to the back ends of the shocks. The problem is that, if memory serves, many of those simply rotate the shock shaft in the body 90degrees, so that the eyelet will only pivot side to side, not fore/aft. If you were to do this, it would compromise your lateral stiffness even further than it already is.

Also, I think that many of those DT shocks that you picture use spherical bearings in the eyelets, making it even tougher to get any stiffness out of that connection.

If you really just feel like messing about with the bike, you could craft some sliding delrin blocks, that would brace the seat stays against the seat tube, like on the early Intense M-1s before they added in the swing links, which would add some stiffness back in.

It could be fun to mess around with, but if you really plan to ride the bike, I am guessing you would finish the modification, ride it once, and then put it right back in the stock mode once you see how poorly the new setup rides.

BTW, if weight savings have anything to do with this plan, ditch that quick release seat clamp, strip the paint off that frame, swap any remaining steel bolts to ti...and forget about swapping the shock unless you find a lighter one that will work in the stock configuration with the swing link.


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PostPosted: Fri Feb 07, 2014 10:15 pm 
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Joined: Sat Nov 10, 2007 4:23 am
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Location: Poland/Toronto
A carbon fibre link for Spark frames was done by Nordischer Rahmenbau a while back. If you could still get one that would save weight and keep all intact. Off top of my head that mod. saved ~50g

Chris.

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MSC Koncept Carbon Di2 - 6955g
Leichtkraft Team Carbon - 6868g.


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PostPosted: Sat Feb 08, 2014 1:17 am 
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I gave up! there is a lot more to consider for this kind of project, bottom line I believe to be unrealistic. Better to keep things the way they suppose to be! Rethinking this idea its not only unrealistic but I can see down the road a potential catastrophic failure on the frame, catastrophic crash... Bad idea overall! Lol

I know there are other companies out there still making this design....but I will leave with the Pro's, not the kind of garage work for this.

Well... I was glad to post the idea anyway and learn something...new information is always welcome!

Thanks!


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PostPosted: Sat Feb 08, 2014 9:16 am 
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Location: Lithuania
Also part of rear suspension travel would be lost, quick guess about an inch.


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PostPosted: Sat Feb 08, 2014 4:25 pm 
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nikonas wrote:
Also part of rear suspension travel would be lost, quick guess about an inch.


Yes...funny how when we start having so many questions and theories...I'm glad I did myself a favor to share and ask opinions before permanently damaging my frame... at least now google images has the very only spark frame with a DT swiss shock on this design on the planet!...but Photoshopped! :thumbup:


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PostPosted: Sat Feb 08, 2014 10:33 pm 
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nikonas wrote:
Also part of rear suspension travel would be lost, quick guess about an inch.


Yeah, but you'd pretty quickly get all that travel back and more... when the shock gets snapped sideways off the linkage.


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Posted: Sat Feb 08, 2014 10:33 pm 


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