Rockshox Judy rebuilding questions.

[wesmamyke]

I've a bunch of dumb Judy questions if anyone can help. Thanks in advance.

Couldn't quite find the information in some of the older threads on Judy forks, and it doesn't help half the pictures have evaporated recently.

After sorting through a giant pile of Rockshox parts and splitting it into Judy and Mag piles I'm still a few bits short.

Is there a non bicycle specific equivalent to the wavy washer that goes under the cartridge? Even after pulling some whole forks apart I only have one of these things.

What is the elastomer stack height for XC and SL forks? I have two different length elastomers here, not sure how to achieve the correct stack height/length.

What forks used a 50mm cartridge? Mostly I have 63 and 80mm stuff I think, but a couple really short carts with one clearly marked 50mm.

Is there any way to run newer one piece lowers with older internals? As far as I can tell the only difference is the size of the hole in the bottom is larger. It doesn't actually need to seal anything so could I use the smaller bolt and a spacer? The one piece lowers have the advantage that I could actually get seals for them.

 

[ishaw]

Re:

You can certainly use newer uppers on the older CSU/uppers. The bolt size issue you can work around. The englund air cartridge upgrade for Judy forks worked this way, and were supplied with a washer/insert to achieve this. There is a seal of sorts when it is all bolted together, but not in the sense it's keeping oil in.

Wavy washers should be available. I'll check to see if I have any spare.

Early Judy forks were available with 50mm cartridges.

Can't help on stack height, but if you have the skewer type adjuster, the elastomers should practically fill the skewer with just a small bit of the skewer visible that then seats onto the plastic bit that sits on top of the damper shaft.

 

[Thias]

Not totally on topic, but maybe the pictures are inspirational:
http://www.retrobike.co.uk/wiki/Special ... conversion

Do you have a functional aluminium-case dampening cartridge? If yes, use it rather that the old plastic versions.
If your elastomeres are shot, try to get steel coils instead. They are a bit heavier, but will last forever.
And if you can get your hands on a cheap Hydracoil Judys, consider the conversion of the whole insides as described in the link above. Its totally worth it.

 

[rva]

first you will need this: http://www.mtb-kataloge.de/Bikekataloge ... judyxc.pdf
the MCU stack is 6 pieces together. Last time I've measured one original it was 27-28mm in height but that's well after 20 years of use.

 

[Thias]

No, not all Judys have those 6-stacks. There are Judys with coilspring/Elastomere stacks, Solid stacks and maybe even other versions that I haven't seen before.
You can roughly measure the needed stack height by assembling the fork and measuring into that hole. "Depth of hole" minus "Adjusting knob height" +1cm should be about right.

 

[wesmamyke]

I have a pretty good choice of cartridges in 63mm. Came across a giant pile of parts and now have a Risse, White Brothers and several aluminum Rockshox carts to chose from. Leaning towards the Risse as they still exist, no reply from them yet about rebuild parts though.

The coil spring conversion was actually part of my elastomer question, have several sets of White brothers and what appear to be later Rockshox springs. Wanted to know what length they should be in case I swapped out for the coils.

Thanks for the link to that wiki thing, was looking for that. That brings up another question, In looking for 28mm RS parts I've come across 28mm oil seals. Was it only SID and hydracoil forks that actually had oil seals under the dust wipers? Do the original two piece lowers have room for and the correct seat to install oil seals?

 

[ishaw]

Re:

The oils seals should fit, I believe as the damper was different in these forks you need them to keep the oil in. If using the sealed dampers like risse etc, you don't need them I don't think. I'm well versed in the older Judy forks but not hydra-coil so am no expert in that area.

Springs are indeed a worthwhile upgrade over elastomers.

 

[FluffyChicken]

Re:

1995 =50mm cart and only that year.
1997 moved to spring +coil type2 setup and newer style seals and one piece lower (for most of them)
1998 moved to type 3 springs coil+coil.
After that it was Hydrocoils and full length springs.

Most are 6.5" or 7" full stack iirc.

I can be more specific if needed.

Gallery&Archive has all the docs you need under RockShox.


Post some pictures up

 

[Thias]

Iirc the oil seals fit all one peace lowers. And the SIDs. Bit they wont fit the early version Judys with those wipers. But those can fit standard wiper seals like shown in my wiki page.

Oh and be careful not to mix up short cartridges with long dummy legs! Or else the cartridges will be blown apart.

 

[FluffyChicken]

It reminds me, how do you find the 28 ID seals on the Judy, I know on the Mags if I drop that much they pretty much lock up if I manage to get the seal on to it (25 from 25.4) and here it's from 28.6.