Hiddenset Stack won't compress- Planet X Pro SL

timdanaher

Decided to try out the headset / fork fit on my new PX Pro SL... cannot get the stack to compress.

Fitted Campag Hiddenset -- so bearing shoulders are the correct 45-deg for the headtube.

No matter what I try, it won't compress. The reason I bought this frame is because my Chinese Ti frame had an irreducible amount of Play in the headset -- assumed it was a badly-machined headtube, but it might have been me all along.

1st q. I've tapped on the crown race, no prob. The Campag instructions say to simply place the bearing race on top of the crown race... It doesn't need to be tapped on like the crown race? (see pic -- looks like a lot of air between crown & bearing races. Bearings are on right way round, sorry about the blur.)



I haven't cut the steerer down, yet... but I've enough spacers to give a 3-4mm upstand from the steerer top.

BTW, I'm using a Dedacciai carbon bung... one with the rubber bands and knurled 'leaves'. Anyone know of a good carbon bung that doesn't use this system.. It keeps falling apart in the steerer tube.

Here's the top cap with the bung done up tight.:



I pushed the nylon washer down as far as it would go before tightening the bung.

Any ideas?

Did I mention that I really hate Aheadsets?

maddog 2

what's that orange thing doing? seems to me that it's sitting between the bearing race and the crown race, which would explain the problem.

Difficult to tell from the pic but the orange thing looks like a simple cover to stop crud getting in so it should sit under or more likely around the crown race, to form a seal and do its job. That way the bearings can sit directly on the crown race, metal on metal.

bazbadger

Have you got the bearings on upside down? Like the previous poster said, the bearings should sit directly on the race - so I presume the orange seal is in the wrong place ?

timdanaher

Cheers, Both -- here's the Campag instro's:



Then, as you can see, the bearing race & seal assembly fits over the crown race:



And, yes, the bearings are in the right way up...

BTW, I've just noticed that with the top cap done up as tight as poss., the spacers above & below the stem can still revolve freely. That can't be right, can it?

timdanaher

bugger. Double post.

maddog 2

TimDanaher wrote:

And, yes, the bearings are in the right way up...

Correct

BTW, I've just noticed that with the top cap done up as tight as poss., the spacers above & below the stem can still revolve freely. That can't be right, can it?

First off, you don't want to be tightening the top cap "as tight as possible" - the top cap is only to preload the bearings - in other words, just take out any play. Do it up tight and you'll push the bearings into the bearing surfaces and knacker them!

Secondly, if you still have play even when the top cap is tightened then you may need more spacers - sometimes the top cap can't take out the play because it is pressing down on the steerer, rather than pushing the spacers+stem downwards.


I still think the problem is the orange thing. Anything that gets between the bearings and the crown race is a problem!

Just take it off and see if it fits together properly. If it does then you know that's the culprit, and you need to reassemble it in some way such that the orange thing isn't in the way (but still acts as a dust guard)

maddog 2

there's an adjustment vid here http://www.youtube.com/watch?v=RRFqU07u ... re=related

timdanaher

maddog 2 wrote:

TimDanaher wrote:

And, yes, the bearings are in the right way up...

Correct

BTW, I've just noticed that with the top cap done up as tight as poss., the spacers above & below the stem can still revolve freely. That can't be right, can it?

First off, you don't want to be tightening the top cap "as tight as possible" - the top cap is only to preload the bearings - in other words, just take out any play. Do it up tight and you'll push the bearings into the bearing surfaces and knacker them!

Indeed, it should all just push-fit together, then tension up with the top-cap. But it doesn't

Secondly, if you still have play even when the top cap is tightened then you may need more spacers - sometimes the top cap can't take out the play because it is pressing down on the steerer, rather than pushing the spacers+stem downwards.

Hmmm... Ive got 3-4 mm of spacer proud of the top of the steerer, so the top cap must be pushing down on the spacers, not the tube...

I still think the problem is the orange thing. Anything that gets between the bearings and the crown race is a problem!

http://www.youtube.com/watch?v=xHS3XxnRqew

look at the above vid -- the order of assembly is correct (the seals are white in the video). I think the problem is the nylon collar not getting pushed down far enough at the beginning -- it's holding evrything apart... notice how they use an inverted top-cap to knock it into place.

timdanaher

Errrrmmm... did someone just delete a post? I got a reply notification, but 'Post does not exist' or somesuch...

bazbadger

yep me. Got wrong end of the fork!

Do you need to drive the crown race further onto the fork? Apparantly a piece of drainpipe works quite well.

I've got a PX pro SL myself and spent quite a lot of time tweaking the headset, tho that has an FSA headset. The race on that one is pushed on by hand.

timdanaher

baz --

Yes, a piece of 40mm polypipe & a rubber mallet does the trick nicely for seating the crown race.

It seems to be OK now... although I won't know until I take it out on the road. The trick seems to be seating the nylon 'grip' collar (reversed top cap & poly pipe again) -- if it's not fully driven down it seems to resist the stack compressing.

Although the fact that the race holders sit so proud of the head tube is a bit troubling. Looks like gunk could get in there.

Oh, and a recommendation for a decent bung for a carbon steerer (no rubber bands, please) wouldn't go amiss!!