Chris King Headset Query

Captain Fagor

A while back I got a new bike frame with a Chris King NoThreadset fitted.

I just started the bike build this evening and the top bearing cap (i.e. this bit: http://www.chainreactioncycles.com/Mode ... delID=9222 ) was too tight to fit over the steerer. Perhaps foolishly, I've just spent the last two hours (!) gently filing away to increase the inside diameter by about 0.15mm (measured by vernier gauge) so that it can be pushed down the steerer without excessive effort.

Now that I have finished this, it strikes me that perhaps it's supposed to be a difficult press fit. The Chris King website ( http://www.chrisking.com/tech/tech_headsets.html ) doesn't clarify. In my mind a press fitting headset bearing cap would make it a royal pain in the arse for removing, and also for cutting the steerer. But otherwise there seems no way of stopping fork play.

Does anyone have any knowledge or experience of fitting NoThreadsets when the bearing cap does not fit onto the steerer? Any thoughts appreciated.

Pirahna

Why would a Chris king be any different to any other headset?

The top cap should slide over the fork steerer with any resistance being in the O ring. The press fit discussed in the link is for the headset into the frame head tube, not the top cap. If the cap was an interference fit, then either the forks are slightly oversize or hole in the cap is too small. Either way it doesn't matter, sounds like you've solved the problem so enjoy your bling new headset.

synchronicity

Are you absolutely sure you pressed it on hard enough?
They do come with a rather tight fitting o-ring seal you know.

Captain Fagor

Pirahna – it never crossed my mind that the top cap function on a Chris King headset might be different until the filing was complete. But then it struck me that unless there’s a hidden split compression ring somewhere in the headset to grip the forks, then there’s nothing to stop the forks rocking within the confines of the hole in the top cap.

Time will tell once I get some compression into the headset. Which is easier said than done as the fork steerer (star fork on an '07 C50) is definitely slightly on the large side – my carbon spacers don’t fit over the steerer. AAaarrgghh – WTF??!!

Synchronicity - I'm not sure if you're at the wind-up or if you have had this particular problem too. Before my filing, the top cap could not be forced on by hand (with the o-ring removed).

gkerr4

doesn't the C50 have proprietary sized steerer bearings - wider again at the bottom a bit like some of the specialized bikes?

just a thought. could easily be wrong.

Captain Fagor

Not that I am aware of gkerr4.

gkerr4

my mistake - it appears to have a regular 1 1/8th

it does have a rather weird 28mm seatpost though (?)

Captain Fagor

It does indeed. I bought a step down ship so that I can use a 27.2mm seatpost. Very odd.

Pirahna

Looking on the Chris King site there is a piccy of what you should have in the owners manual:

http://www.chrisking.com/pdfs/NoThreadSet.pdf

Looks like the top cap is the only thing to stop side to side movement of the forks, so I would think it needs to be a fairly tight fit.

topcat1

Captain, the bearing cap is a tight fit, i've fitted a Chris King no threadset to my road bike and mountain bike. It does stop the headset from rocking loose.

Captain Fagor

Thanks for the feedback. I was offline today, building the bike including cutting the steerer - a process I never enjoy! I think I got my filing about right, as the bearing cap just squeezed on with the o-ring in and there's no play in the headset.

The only remaining issue is the bottle cage bosses. Again, either the lacquer is preventing use of a standard bottle cage bolt, or Colnago uses a smaller bolt diameter. If it wasn't for that issue, tomorrow would be the shakedown ride - bummer!