Author Topic: Rock Shox help (Read 2934 times)

Robh · « **on:** 07 March, 2018, 12:02:43 am »

I’ve taken on a project that involves a set of Rock Shox Paris SL forks. In a life time of cycling, I have managed to avoid suspension forks, and I don’t know where to start with getting them to work as I think they ought to. Can anyone point me at a service/maintenance manual for these things? Failing that, any advice would be helpful.

TIA

LittleWheelsandBig · « **Reply #1 on:** 07 March, 2018, 01:15:07 am »

I thought the Paris-Roubaix was a hot-rodded variation on the Mag-21. I'd check for a manual for those and take it from there.

Torslanda · « **Reply #2 on:** 07 March, 2018, 01:29:48 am »

There's some chatter on retrobike.co.uk which might take some wading through.

I've never seen a set in the flesh but I would expect them to be fairly simple elastomer 'springs' with friction damping. If you pull them apart and find the elastomers - foam rubber cylinders which stack one on top of another to make the spring - crumbling, an ebay search may turn up an American coil spring conversion which will restore the performance. This is what I did with a pair of Quadra 21 a while ago.

Sorry it's a bit vague but they were never a common fitment and your best move might be sourcing a replacement rigid fork.

LittleWheelsandBig · « **Reply #3 on:** 07 March, 2018, 01:31:39 am »

Mag-21 and PR are air/oil forks.

Brucey · « **Reply #4 on:** 07 March, 2018, 06:51:57 am »

IIRC the Rockshox website used to host all the old manuals for their forks. Maybe the current (SRAM) site has them somewhere. If not, maybe they can be had via the wayback machine.

cheers

Dave_C · « **Reply #5 on:** 07 March, 2018, 07:24:46 am »

It is pretty straight forward to do. I serviced my 120mm Rock Shox SL last winter. You don't need any special tools. I bought the service kit from Chain Reaction, which comprised of 2 foam washers and 2 rubber seals. I bought some oil from my local bike shop, and the Red lube online. I can't fin the original stuff but this is the same - here:

https://www.jejamescycles.com/rockshox-suspension-oil-120ml.html

and watched this video a few times.

https://www.youtube.com/watch?v=f0-H-Gd6QM0

I also took an old large flat screw driver and filed the end to make it rounded, so when I removed the old seals I did not scratch the inside of my forks.

Local servicing should be around £60 - £80 depending on where you take it.

Torslanda · « **Reply #6 on:** 07 March, 2018, 08:15:34 am »

Quote from: LittleWheelsandBig on 07 March, 2018, 01:31:39 am

Mag-21 and PR are air/oil forks.

Big bike pumps then . . .

Was it the Ruby that had elastomers?

LittleWheelsandBig · « **Reply #7 on:** 07 March, 2018, 08:27:00 am »

I'm not familiar with the Ruby but I think you are probably right.

Brucey · « **Reply #8 on:** 07 March, 2018, 08:35:29 am »

on the subject of tools, on older rockshox the most common arrangement would be that you had plastic top caps, with a hexagon fitting of various sizes. These caps are often difficult to remove if they have not been disturbed for some time.

My advice is to seek out a full-hexagon (not bi-hex) tool with no relief or counterbore on the entry so that you get the maximum engagement with the plastic hexagon fitting on the top caps. I have found that the OEM toolkits for 1980s and 1990s Japanese motorcycles contain flat spanners that are pretty good for this kind of task.

cheers

Robh · « **Reply #9 on:** 08 March, 2018, 04:21:22 pm »

Thanks for the suggestions. I'm a bit further down the road, but I may just end up binning them.

The bike is an eBaY purchase: an old Stumpjumper, circa '98, that I intend to build up as a fun/utility bike for my daughter. I had a '96 Stumpjumper that I passed onto to her boyfriend and it's been such a hit in their household that she ordered me to find another for her.

LittleWheelsandBig · « **Reply #10 on:** 08 March, 2018, 05:48:47 pm »

The Paris-Roubaix fork was a very limited edition fork for 700C and sidepull brakes. Why would a fork like that be on a Stumpjumper? A couple of pictures would help minimise potential confusion.

Torslanda · « **Reply #11 on:** 08 March, 2018, 09:08:53 pm »

Yeah. I could see them being Judy SL . . .

Robh · « **Reply #12 on:** 10 March, 2018, 12:20:24 am »

Some pics:

spesh · « **Reply #13 on:** 10 March, 2018, 12:29:54 am »

That looks like a Mag 21 fork to me.

LittleWheelsandBig · « **Reply #14 on:** 10 March, 2018, 05:10:43 am »

It definately isn't a Paris-Roubaix SL but it does look a lot like a Mag-21.

Chris N · « **Reply #15 on:** 10 March, 2018, 05:40:46 am »

It looks like a Paris-Roubaix (amount of exposed stanchion tube, no fork boots, stanchion colour, stickers nicely applied and in the right place) with retrofitted Mag 21 brace and brake mounts to me.

Torslanda · « **Reply #16 on:** 10 March, 2018, 08:19:36 am »

Sorry Rob, I think he's right.

It's either been badged or bodged...

Polar Bear · « **Reply #17 on:** 10 March, 2018, 08:28:45 am »

All of the images that I can find show the fork to have a bridge for caliper brake attachment. I recall that in the nineties there was a craze for modding forks but this was mainly internals dumping elastomers for springs and oil.

Brucey · « **Reply #18 on:** 10 March, 2018, 08:51:01 am »

IIRC the road forks were -despite GDL's efforts- not a big hit at the time; for example I think the last Ruby forks were sold off at £50 a pop retail, a tiny fraction of their original asking price.

To anyone canny the right set of road forks may have represented an 'instant rebuild kit' for a MTB fork that used the same stanchions and sliders. Maybe that was what happened here.

They are not complicated inside if (say) MAG 21 innards were retained, BTW. There is considerable scope for improving the action of such forks to suit individual riders, if you have some workshop skills and some time on your hands.

cheers

Robh · « **Reply #19 on:** 10 March, 2018, 11:50:44 am »

Thanks for the feedback. I'll probably replace them - does anyone know where I can get a suitable set of unicrown forks?

To be honest, I suspect that the frame may not be a Stumpjumper either - it's been resprayed (by Argos) and, when I asked the seller, he said that he only had the word of the shopkeeper he bought it from to testify that it was a Stumpjumper. But it's a sound frame and it will provide a good starting point for the project. It will just end up costing a bit more than I originally intended :-(

Torslanda · « **Reply #20 on:** 10 March, 2018, 12:40:56 pm »

Finding decent quality suspension forks with canti mounts might be a touch, er, challenging.

Obviously there's the ubiquitous Suntour XCT or Top Gun or RST (and a million & one others on ebay) but they're heavy, clunky and probably not well matched to your frame. Even 100mm of travel might be too much for the head angle.

These might do the job

Rigid forks can be found. Many LBS - especially if they've been around a while - will have used or NOS cr-mo forks in the cellar. Mainly because we can't throw anything away!

The Family Cyclist · « **Reply #21 on:** 10 March, 2018, 09:32:17 pm »

Rob did you want to stick with suspension or would rigid do?

Robh · « **Reply #22 on:** 10 March, 2018, 09:46:06 pm »

I'm going to go with rigid. Do you have something?

(As it happens, I just saw your wanted list, and I think I might have a v-brake mech in the shed somewhere, but I would need to check tomorrow.)

LittleWheelsandBig · « **Reply #23 on:** 11 March, 2018, 05:44:40 pm »

Quote from: chris n on 10 March, 2018, 05:40:46 am

It looks like a Paris-Roubaix (amount of exposed stanchion tube, no fork boots, stanchion colour, stickers nicely applied and in the right place) with retrofitted Mag 21 brace and brake mounts to me.

I sit corrected but it seems a stupid thing to do to a rare fork.

Author Topic: Rock Shox help (Read 2934 times)

Chris N