Specialized Demo 8 / 3-5mm play in S-Link frame pivot.

CitizenLee

Alreet folks,

Just got my 05 Demo 8 (recently bought 2nd hand) back from my LBS after getting new wheels built and new drivetrain fitted but I have noticed a considerable amount of play in the rear S-Plate pivot bolt. The bolt is as tight as the big S recommend (maybe a bit more) but you can grab the S-Link and move it from side by about 3-5mm.

I disassembled the main pivot last night and all parts are in place as they should be, according to the exploded diagram in the Demo 8 tech manual. See my modified version below:



Before I took it all apart I thought the S-Plate was moving on the bearing but this isnt the case… as the bearing is seated into the S-Link in a small lip / ridge.

I think the problem is the inner diameter of the bearing lip is larger than the outer diameter of the 4mm washer… so S-Link is free to move the 4mm between it's inner face and the frame. I hope that makes sense.

It's baffling me as it seems to be set-up the way it is supposed to be… but I cant see it having ever worked like that as no parts are missing and nothing appears to be broken…. so why the play?

I have a replacement bearing kit on order but I'm not 100% convinced it will remedy the problem.

As such I was thinking about getting some custom washers made up. I originally thought that I could get some 1mm thick x 28mm O.D x 15mm I.D washers and then just fill the gap with them, but then it dawned on me I would still need the 4mm chamfered washer in place (which is 4mm thick x 23mm O.D x 15mm I.D).

In which case I could get some custom ones made that are 1mm thick x 28mm O.D x 23mm I.D to sit around the 4mm chamfered washer but still fill the gap.

I'm unsure this would be the best way though.

I did contact the big S but they just suggested getting my LBS to fit a new bearing kit and if that didnt work then send the frame to them for inspection.

Any help, advice or suggestions would be much appreciated.

Cheers,

Lee

nicklouse

closer inspection needed. and you need to work out what is actually moving on what.

assemble with out s link any play? assemble with out frame. where is it and what is moving?

CitizenLee

Here you go Nick, this might help....

http://www.pinkbike.com/video/3922/

The bolt is as tight as it should be and the bearing is seated correctly in the S-Link so I can only conclude the play is coming from the gap in between the frame and the inner face of the S-Link, where the 4mm chamfered washer sits.

There's no play in any of the other linkages / pivots and when assembled without the frame you cant tell as there's nothing for everything to rest against, if that makes sense.

Cheers

CitizenLee

I took it all apart again last night and took some more photos... see here:

http://citizenlee.pinkbike.com/album/Demo-8-Pivot/

In doing so I think I might have came a step closer to discovering the problem.

The bolt is fully tight against the bearings, 4mm washers and frame, so that rules out any play from those parts. The play is definately coming from the s-link moving on the bearing. The inner lip that the bearing sits on has a larger I.D than the O.D of the washer so because the bearings can pop in and out easily, it means play develops, despite everything being tight.

I called my local Specialized dealer and after explainig the problem they assured me the bearing should not be easy to remove from the s-link. They should be a super tight fit and can only be installed using a FSR bearing press. Well, I can pop then in and out with my finger.

There is the possibility that the bearings could just be goosed but depending on how long the bike has been used in this state it could also mean that s-link bearing housings have ovalised. I fear it could be the latter as one of the bearing hits a tight spot when pressing it in, although it's still easy enough to push in by hand.

I then called Specialized UK and whilst they echoed the above, they also suggested I try some "green" loctite as they have fixed a few bikes with similar issues with it. The green stuff is a retaining compund specifically for things like press-fit bearings that do not fit nicely into their housings etc.

Loctite RC680 is the exact stuff I need however the its like gold dust here in the UK... super hard to find. I'm sure I will find some though, and then I can see if that solves the problem. It does specifically say in the tech manual to use green loctite so with any luck it will fix it.

Failing that I can get a new S-Link for £40 which isnt too bad really... considering how much the bike is worth.

Also, I've sacked the idea of custom washers as if all the parts are correctly fitted then there should be no need for anything else.

Now to find some Loctite RC680 in the UK!

Cheers,

Lee

nicklouse

the reads dont look to good.

so the movement is a sideways one? (cant see the vid) not a worn play one.

the axel/bolt and nut have to be at fault. as there is a lip on the inner edge of the link to stop them falling "off".

CitizenLee

Yes Nick, the bolt is a little worn but it still tightens fine. I will be getting a new one with the bearing kit though.

The movement is horizontal but the bolt does not move in the slightest, it is fully tight. and there is a lip in the s-link to stop the bearings falling out.

I'm quite convinced the problem is the bearings are not stuck in the s-link though. I know you cant see the video but take my word that you can see the sl-ink moving sideways on the bearings. The reason it can move even though everything is tight is because the 4mm washer has a smaller OD than the ID of the bearing lip on the s-link. If the bearings were set in place then this would not be an issue. I've been told they should be too tight to install or remove by hand. So either the bearings are worn or the s-link has ovalised.

I'm going to try some "green" Loctite (680 grade I have since discovered) as Specialized suggested and if that doesnt work I can get a new s-link for £40 which isnt too bad.

Also, if you look at the link below you will see 680 is used to install bearings on Santa Cruz Nomad frames so it must be the right stuff. Specialized only suggested "green" loctite rather than a specific grade (see page 15 of the Demo 8 tech manual I posted above).

http://www.jungleproducts.co.uk/worksho ... rhaul.html

I also have a couple of bearings on order from www.enduroforkseals.com to see if they are any better than the Specialized ones.

Cheers for your help.

Lee

EDIT: Looks like I didnt post the full tech manual above so here it is:

http://www.specialized.com/OA_MEDIA/pdf ... ual_05.pdf