Replacement for the MCU springs in a 1996 Judy RockShox

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Date: 01 Sep 2007 07:46:32
From: eganders
Subject: Replacement for the MCU springs in a 1996 Judy RockShox

I have a 1996 RockShox Judy fork. I just noticed that the MCU
(microcellular urethane) springs have collapsed. I don't want to
change out the fork, it just is not worth it. Is there a way to
replace these "springs" with either a urethane material or a standard
spring? Has anyone found a way to replace these with something?

Date: 02 Sep 2007 09:21:59
From: bjw@mambo.ucolick.org
Subject: Re: Replacement for the MCU springs in a 1996 Judy RockShox

On Sep 1, 8:21 am, "Dave Mayer" <dave4...@hotmail.com > wrote:

> Last year I replaced these forks with new 1996 Judies that had been hanging
> on a shop wall. They had been cut too short for a customers bike, but they
> were plug and play for my frame. These are not high performance forks by
> modern standards, but they were really cheap, and they are good enough for
> my moderate MTB needs. I would suspect that the piles of 'SR Suntour' and
> the like forks that clutter the back rooms of bike shops from customer
> upgrades would be as good as the old Judy shocks. One local shop here ended
> up throwing away dozens of these inexpensive forks, as they have no
> aftermarket value.

Perhaps surprisingly, those cheapo forks may still
not be up to the performance of a dented old Judy.
I haven't looked at them closely recently, but it
used to be that cheapo forks had small-diameter
upper stanchions, often made of steel - so they
were both heavy and not particularly stiff - and
no real damper, so they were missing one major
component of shock absorbers. They're pretty
much suited for riding off curbs, which is what
most of them are used for.

Ben

Date: 02 Sep 2007 09:15:16
From: bjw@mambo.ucolick.org
Subject: Re: Replacement for the MCU springs in a 1996 Judy RockShox

On Sep 1, 10:07 pm, eganders <egand...@yahoo.com > wrote:

> I removed the MCU springs and checked the bushings in the fork.
> Everything in the fork appears to be like new except the MCU springs
> which have all the red (soft) springs disintegrated and one of the
> purple ones in bad shape. I am looking into getting some urethane rod
> stock of several durometers. I am suspicious of using metal springs
> because of the short stroke in these shocks. I think urethane has a
> sharper, non-linear rise in springrate. What are Speed Springs? I
> could not find much on the internet about them. I have only done a
> short search, however.

Eons ago when the world was young, a vast evolutionary
diversity of mountain bike parts manufacturers sprang
up to colonize fertile territory, and lo! parts sprang
forth upon the earth, and it was good, except some of
these parts were made of cheese, and lo! yet more
tiny machine shops sprang forth to make upgrade parts
for the cheesy ones, and indeed for the "trick" value,
and it was good, except when it was made out of
too-heavily CNCed aluminum, and then it wasn't so good,
but it did look cool in blue anodization.

The Judy was like that - it was a great fork, except
for the fact that the parts stank. So there was a
micro-industry of upgrade parts: springs, cartridges,
whatnot. Speed Springs were coil springs made/sold by
Mountainspeed as a replacement for the elastomers (and
for a variety of forks, not just Judys).

http://www.mtbr.com/reviews/Shock_Upgrade/product_22873.shtml

They work fine. I still have a pair in a Judy.
I wouldn't worry about the difference in spring rate
between elastomers and coils. Your problem will be
finding some. In theory, any coil spring that was the
right length, diameter, and spring constant could
work, but it might be difficult to find that.

Ben

Date: 01 Sep 2007 22:07:15
From: eganders
Subject: Re: Replacement for the MCU springs in a 1996 Judy RockShox

On Sep 1, 1:43 pm, "Bellsouth Ijit 2.0 - Global Warming Edition =AE"
<b...@bellsouth.net > wrote:
> "eganders" <egand...@yahoo.com> wrote in message
>
> news:1188657992.123340.197950@d55g2000hsg.googlegroups.com...
>
> >I have a 1996 RockShox Judy fork. I just noticed that the MCU
> > (microcellular urethane) springs have collapsed. I don't want to
> > change out the fork, it just is not worth it. Is there a way to
> > replace these "springs" with either a urethane material or a standard
> > spring? Has anyone found a way to replace these with something?
>
> I have 96 Judy XC that I replaced the innards with Speed Springs a long t=
ime
> ago and is still going. Some friends had mixed results w/ Speed Springs
> however, mostly due to improper installation. It also helps to install
> aftermarket seals. White Bros used to make replacement elastomer kits, and
> some others I can't recall. As far as availability, not sure. Cambria
> Bikes used to carry some.

I removed the MCU springs and checked the bushings in the fork.
Everything in the fork appears to be like new except the MCU springs
which have all the red (soft) springs disintegrated and one of the
purple ones in bad shape. I am looking into getting some urethane rod
stock of several durometers. I am suspicious of using metal springs
because of the short stroke in these shocks. I think urethane has a
sharper, non-linear rise in springrate. What are Speed Springs? I
could not find much on the internet about them. I have only done a
short search, however.

Date: 01 Sep 2007 13:43:13
From: Bellsouth Ijit 2.0 - Global Warming Edition Ž
Subject: Re: Replacement for the MCU springs in a 1996 Judy RockShox

Date: 01 Sep 2007 15:21:22
From: Dave Mayer
Subject: Re: Replacement for the MCU springs in a 1996 Judy RockShox

"eganders" <eganders@yahoo.com > wrote in message
news:1188657992.123340.197950@d55g2000hsg.googlegroups.com...
>I have a 1996 RockShox Judy fork. I just noticed that the MCU
> (microcellular urethane) springs have collapsed. I don't want to
> change out the fork, it just is not worth it. Is there a way to
> replace these "springs" with either a urethane material or a standard
> spring? Has anyone found a way to replace these with something?
>

About 5 years ago I replaced my first year (1995) Judy guts with springs.
The springs came as part of an upgrade kit sold by Rock Shox. These sold on
Ebay from time to time. Make sure you select the spring with the correct
weight rating.

Check to see if you fork bushings are not worn out. Does the fork have play
front and back when the front brake is locked? Years ago I knew a mechanic
who could replace bushings on these old forks, but the parts and skills are
probably gone.

Last year I replaced these forks with new 1996 Judies that had been hanging
on a shop wall. They had been cut too short for a customers bike, but they
were plug and play for my frame. These are not high performance forks by
modern standards, but they were really cheap, and they are good enough for
my moderate MTB needs. I would suspect that the piles of 'SR Suntour' and
the like forks that clutter the back rooms of bike shops from customer
upgrades would be as good as the old Judy shocks. One local shop here ended
up throwing away dozens of these inexpensive forks, as they have no
aftermarket value.