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 Post subject: halson inversion forks
PostPosted: Thu Mar 19, 2009 9:51 pm 
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http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0364400335


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PostPosted: Fri Mar 20, 2009 10:58 am 
retrobike rider / Gold Trader
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Joined: Fri Dec 21, 2007 1:06 pm
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Location: The Peth
Looks like a pair of 94' Halson Designs Inversion Forks....

Mountain Biker International wrote the following about the forks :

"An upside-down fork featuring long elastomer bumpers which can be removed in seconds by undoing 2 dials on top of the legs. New bumpers can be fitted to the 6" long rod, kebab style. The fork offers a claimed 1.9" of smooth, progressive travel and weighs in at around 3lbs.

Instead of being fixed permanently, the cantilever brake bosses slide up and down. They are fixed to the inner legs and stick out through a hole in the outer legs. Upside down forks are stiffer and handle better due to more weight being up top.

The alloy fork brace might not be the stiffest but the upside down design places less stress on the legs so Halson can get away with a downgraded brace"

Weight : 3.25lbs
Price : £285 (as of 94')

Gotta be worth a punt for someone....they'll probably go cheap :wink:


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PostPosted: Fri Mar 20, 2009 12:46 pm 
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I had some on my Explosif in 1996 for a few weeks. Far more flexible than the Manitou 3/4 I had before or the Mach5's I replaced them with.

Interesting design.


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PostPosted: Fri Mar 20, 2009 12:58 pm 
retrobike rider
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i have 3 pairs kicking arond, so have my eyes on these, loved them when they were on my Lava dome


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PostPosted: Fri Mar 20, 2009 5:01 pm 
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Could do with using a flash to take a pic. :roll:

If these are upside-down forks why does it look like the boots are on the top of the fork and not the bottom? :?


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PostPosted: Fri Mar 20, 2009 5:48 pm 
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Xesh wrote:
Could do with using a flash to take a pic. :roll:

If these are upside-down forks why does it look like the boots are on the top of the fork and not the bottom? :?


ahhh that the clever bit :wink: …& THAT INVERTED FORK
An inverted suspension fork is a great idea on paper. The strongest part of a fork needs to be at the top, next to the crown. It makes good engineering sense to use the large-diameter alloy part on the top, and put the smaller-diameter, moving part on the bottom. Not only is this a better use of materials, supporting the bearings and sealing its moving parts is made easier with an inverted arrangement. Known as "upside-down forks," the idea has been borrowed from motorcycles (even though professional motorcycle racers are returning to right-side-up forks).

The fly in the ointment of upside-down forks is the brakes. They must be close to the rim, and that means ten inches above the front axle. Since the upper part closest to the rim of upside-down forks doesn't move, it's hard to get the brakes to follow the rim. This problem has sidetracked most inverted fork concepts into the waste can. Halson Inversion forks solved this problem by slotting the upper alloy section of its fork. The cantilever bosses move up and down inside the vertical slots without having to depend on a disc brake. You get superb bearing overlap, increased rigidity and less unsprung weight (the part of the suspension that follows the ground on upside-down forks).

There are no contact seals (oil or dust) in the Inversion fork. One all-enveloping rubber boot seals the lower legs, brake bosses and moving brake bridge. No contact seals means less stiction and better low-end suspension performance. The forks come with a million elastomer elements in different durometers for fine-tuning purposes. To remove its elastomer shish-kebab, unscrew the caps on the top of the fork crown and the entire assembly pops out.


taken from http://www.ventanausa.com/mba0495.html


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