Speedmachine suspension fork..

[henshaw11]

..has anyone ever stripped down one of these ?

The bearings - or the USS bar pivot, I've yet to investigate - has become notchy, so it could be new bearing time. Or does the fork use bushings ? - looking at the namual there's an upper and lower (splined) bushing, certainly can't spot any bearing races as such..

I've contacted bikefix, who sound like they may not have done many (any?) - tho' to be fair, they're going to go and find out a bit more.

[Arellcat]

Unless they've changed it, the fork slides in two plastic bushings: the upper one is plain, the lower one is splined.  The lower bushing is also splined externally to engage with the outer fork tube, and the outer fork tube is located by the headset bearings.

If the notchiness is in steering, it's probably the headset bearings.  If it's notchy fore-aft, it could be anything. 

Check out my commentary on full disassembly: http://cruise-cat.blogspot.co.uk/2007/05/speedmachine-front-suspension.html

[henshaw11]

Ooh, excellent, thanks Becky !

(I must admit I wondered if you or Dave L might reply, couldn't think of any other SPM owners..).

Yeah, it's just rotational notchiness..your pics explain why I couldn't see any bearings in the SPM manual, 'cos they didn't show 'em..

From reading the SPM manual it sounds like the lower bearing seats on a change of tube dia. - ie like a fork crown, and that the upper bearing is seated at the right height 'cos it sits in the top of the headtube, but has nothing to locate it in height on the inner fork tube otherwise. Do I have that correct ?

The implication from the SPM manual is that I should to get an assembled fork back in the headtube without the aid of a drift (removing spring etc), but it sounds like in reality a bit more violence might be needed..

[Arellcat]

The headset bearings are located like those on a motorbike: set directly into the head tube.  So you tap the fork assembly out and the upper bearing stays where it is and the lower one comes out with the fork.  I can't remember offhand but I think there must be a slight step on the outer steerer tube to positively locate that bearing, otherwise it would rest on the locknut—which is precisely the bit that needs clearance above it, and would otherwise transfer the suspension loading to the aluminium threads around the splines bearing.

You can put the fork back in without removing the spring first, but it might not be as easy, though I never tried it.  Violence?  Not really; firm persuasion is more like it. 

[Mr Larrington]

It's been a very long time since I last pulled mine to bits so I can't really comment.  The Haynes Manual bilge about "reassembly being the reverse of disassembly" omits to mention "big hammer required"; advice received from Daniel Pulvermuller via Darth Stuart

[henshaw11]

Ta.

Well, it's Darth Stuart that mailed me to say the new headset had arrived in, so assuming it's a sensible price to fit it, it won't be me wielding the hammer...hopefully that's a good thing

Tho' being an engineer (albeit of the electrickery variety) I wouldn't *mind* doing it myself as a matter of curiosity and self reliance, but the list of DIY jobs I have is big enough already, with one sh*tload of kitchen and bathroom caulking at the top of the list