Shocks worth keeping? (now about Halson Inversions/PDS)

[RockiMtn]

thanks Justin!!! awesome contribution to this thread!

so the Halson I have is set up for 180lbs, no wondering i can't budge it. even if the elastomers haven't hardened!

should i degrease everything and then regrease?

so i'm guessing white is softest and red is hardest, what are the other range of colours?

 

[justjustin]

Glad some of this useless information I store is actually worth remembering! :O) Actually, for years I thought I was THE only person who liked the Halson forks anymore.

PDS Poly Hard to soft - Black, Green, Red, Blue, Yellow, White, Pink
(This can be used for the Inversion as well, may need to
make a preload spacer/doughnut to dial it in...)
Here is a good place to start setting up your PDS Poly stack (not tandem):
Pink-Pink ~ 80lbs, Pink-White ~100lbs, White-White ~ 120lbs,
White-Yellow ~ 140lbs, Yellow-Yellow ~ 160, Yellow-Blue ~ 180lbs,
Blue-Blue ~ 200 lbs, Red-Blue ~ 220 lbs, Red-Red ~240+

Inversion Poly hard to soft - Red, Blue, Yellow, White
The last piece on the skewer is the long, slender red. Placing the exact same colors in different orders noticeably changes the fork's behavior,
but the long slender red needs to be last on the ka-bob.
I may have missed a color, so if you have one not listed, please mention it - I may have forgotten but it could also be another brand I suppose.

Going to look for the manuals some more...

 

[justjustin]

Manual and Brochure For Halson PDS Suspension Fork

O.K., I found one of the manuals! And (drum roll please)
two of the original sales brochures they handed out back in 1996.
As I understood, there were from 5k to 7k of the inversions
built, but less than 1,000 of the PDS forks built. Inversion
was made in Taiwan but the PDS brochure says "made in Oregon"
so it was at least assembled here, if not machined as well. I am
going to try and contact the two Halson Designs, Inc. owners
I know of and their attorney and try to see if we can get boots,
or other spare parts from Steve. Maybe build some new PDS's???
How cool would that be!!!???

The manual is Copyright 1996 Halson Designs, though as far
as I can tell, it no longer exist. It is not for resale, and for
Halson PDS Fork owners specifically, as it was included with
every new PDS sold. The manual has no copyright on it,
anyone can have it as far as I can tell. :shock:

Can't edit a PDF or I would have removed the redundant fron cover
of the manual. Too lazy to re-scan it all in after I saw what I had done.

www.justincouch.com/download/PDS_Manual.pdf

www.justincouch.com/download/PDS_Brochure.pdf

Just a "thank you" and your firstborn is payment enough.

 

[justjustin]

Here are a couple of pics from days gone by.
The yellow frame is the one traded from Sherwood Gibson of Ventana
to Steve Wilson for a stack of halson forks back in 1995. My buddy still
rides it. (I unsuccessfully try to buy it back at least once a year )

The orange MPFS is one I built for my wife 1.5 years ago (where one of my spare Inversions went I now remember!!).

 

[RockiMtn]

Awesome Justin!

Those PDS clear boots look sweet! Would they fit the Inversions? I like the way the bootless Inversions look right now on the Blizzard, it be a shame to cover it all up with black!

BTW, I removed the extra cover page you had in the owner's manual. PM me your email and I'll forward it back to you.

 

[justjustin]

The black boots were prone to tearing so with the PDS came a new
boot - much more durable. they were interchangeable, though I think
the black ones were so easily torn I never even tried them on a PDS.

They regularly switched black boots on the Inversions for the PDS clears
when the inversion forks were repaired once the PDS stuff was available.
The Poly can also be mixed and matched pretty easily.

 

[justjustin]

Preloading a Halson Poly stack

I like to preload the Halsons a tad so you don't get sag just from the weight of the bike, and to give a little boost to the rebound rate.

If you did not have a long enough stack, you would lose
some useful travel. I like to make sure that when I am screwing in
a poly stack that there is just a touch of pressure as I am starting to screw in the ka-bob. That way I know I am getting full travel
and the fork will have a little quicker rebound to it's top. this is something
you have to play with a bit, dialing in any fork. Rebound and spring rate
can be changed in the Halsons by doing the color re-arrangement,
preload with a thin slice of a poly piece (teflon washer can work) and
just plain color choice for stiffness/spring rate.Be very careful not to
cross-thread when doing this!!! The aded tension can mask the threading
tension and you may screw up your threads!

The PDS poly is a bit less "bouncy" and more consistent.
It is called an "open-cell" polymer and was chosen for its generally
more desireable properties - sans the bounce.

 

[longun]

the first forks are either tange or sr/sakae.iirc they came as an option on bottom to mid saracens in the 90s.think dawes used them for a while to?

i had some on an old andes fs,used to strip um,regrease the internals and warm the elastomers up and soak um in wd40.worked quite well for a 9stone tennager,till i bent them lol

 

[nimbus]

I've got a pair of Inversions just like the ones in the original post, except a previous owner ground off the canti cable stop from the arch. Also missing the boots.

My forks sag about an inch or so under their own weight, even when off the bike - I suppose this means the elastomer stack is too short? I'll try and post a pic later.

Out of interest, were Inversions only available with 1" steerers, or was 1 1/8" also an option?

p.s. Thanks for posting the manual and brochure.

 

[RockiMtn]

mine's a 1 1/8" steerer

so is there any way of keeping the polymers fresh? can the polys i have be revived if i soak them in something or warm them up?