Headset not sitting right, steerer tube problem?

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too crusty
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by too crusty

Calnago wrote:Wow, from the pic, it doesn't look like there's even enough recess in the headtube to accommodate a normal size bearing. It only looks about 3mm deep to me before the bevel starts, way shallower than the thickness of that bearing. Looks like the headtube has been faced and maybe way too much material removed? In any case, that just doesn't look right at all, from the frame's perspective, but it may be just the photos. :noidea:


I think Calnago is right on this. I would bet the fork is fine and in fact, when you compress/assemble the whole thing together I'm sure it will work perfectly (should not wobble or knock)....its just looks off. Standard bearings would sit deeper into the head tube and stick out the top just a 1mm or so and when you tighten everything down it shouldn't move and a very slight gap between the bearing top cap and top of the heat tube....some manufacturers will supply a rubber gasket to seal that gap off.
Its either what Calnago said or that the upper bearing is wrong, or maybe even the bearing cover cap is wrong.

just my .02

eric
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by eric

I am pretty sure the bearing is not seating because the fork is oversized. The OP said he can't slide the spacer all the way down the straight section of the fork. That's the reason the upper bearing does not seat fully in his pic- the fork is preventing it.

The OP could post a pic of the upper bearing seated in the frame without the fork to show that.

Yes you can sand down the fork. But there's two problems with that- first the result may not be concentric with the axis of the fork. There's some slop allowed there but if it's too far off steering bearings would bind or the bike won't track straight. Second is that you don't know how thick the steerer is there. If it's that poorly made on the outside it could be poorly made on the inside. I'd at least inspect the inside carefully with a bright light. If it was me I'd measure the ID with a bore gauge and micrometer to make sure the thickness is consistent.

Carbon steerer tubes are pretty tough. Try breaking the cut-off when you shorten a steerer. Chances are you can be ok with this one even after sanding it down unless it's really awful inside. But if you're wrong and it breaks it's going to hurt a bunch.

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Calnago
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by Calnago

@eric: unless his headtube is less than about 60mm (and what headtube is that short), that bearing slides down the steertube well beyond where it would be actually sitting when installed, so that's not the issue.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

ihs0yz
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by ihs0yz

Calnago wrote:Maybe I'm missing something.

You actually are :? If you look at the pictures, the compression ring AND bearing will not go further from where it's supposed to be when installed and this seems very likely to be a slightly oversized tube on at section where it's not suppose to. Also from another picture, you can see the compression ring (this is a very long word) and bearing stops way before the steerer tapers, there's a little number tagging on the tube itself that you could use as distance reference. The spacer stopped sliding down the tube before the tapered section as well where the compression ring and bearing did.

My headtube is 105mm (according to specs..) so yes, technically I wouldn't have to worry about the bearing reaching the tapered section but it did stop before that.

eric wrote:Yes you can sand down the fork. But there's two problems with that-

I'm probably going to save myself from the trouble, have myself a peace of mind and just go with a new fork but thank you :)

I'll try to get some more pictures of how the bearing would sit in the frame without the fork tonight just to see how that will turn out, I remember doing this even with the dust cap.
Last edited by ihs0yz on Fri Nov 28, 2014 1:24 am, edited 1 time in total.

ihs0yz
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by ihs0yz

Sorry double post.

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Calnago
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by Calnago

Ok... after a big ol' Thanksgiving dinner I find myself looking at this once again and feel a little foolish as I didn't really study ALL the pics close enough. It does appear that the steertube is not very uniform. Sorry for possibly leading you down the wrong path, my bad. Still think the top bearing should fit in the headtube more fully than it does however. Did you try a little film of grease on the area where the compression ring and the bearing are binding? I can appreciate your concern that the steertube does not seem to be of uniform diameter. Strange and yes, the LBS should not have given it back to you like that.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

Raineman
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by Raineman

I also have a neco headset and the top of the bearings protude about 2-3mm above the top of the head tube on my dengfu but this is covered up by the dust cover. You can see where the bearings sit naturally from the photo where the compression ring is not inserted and this is the same as my frame, which works without issue. I would say the steerer tube on the fork is the issue as there isn't a uniform diameter after the taper. You could try sanding it down, but if there was a manufacturing to cause the issue in the first place something else could be wrong and sanding could be enought to cause it to fail. Best option is new fork in my book.

glepore
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by glepore

Excess epoxy or something on the fork. I would sand it and ride it, but I'm crazy. I wouldn't advise someone else to do it.
Cysco Ti custom Campy SR mechanical (6.9);Berk custom (5.6); Serotta Ottrott(6.8) ; Anvil Custom steel Etap;1996 Colnago Technos Record

Svetty
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by Svetty

As I understand things the fork has already been safely ridden for many miles without breaking. The likelihood of significantly weakening it by lightly sanding it is negligible.

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bikerjulio
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by bikerjulio

Svetty wrote:As I understand things the fork has already been safely ridden for many miles without breaking. The likelihood of significantly weakening it by lightly sanding it is negligible.


You might think so, but not based on what happened to me a few months ago..............

I too had a no name fork that had been fine for 5 years or so. Then one day after I'd stood up and put the power down, I'm thinking "this bike feels mushy".

About 5Km later I stop to talk to someone and realize my bars can now flex up and down quite a bit.

The carbon steerer had partially disintegrated at the location of the centre of the head tube. The fibres were still connected as I discovered later - but no resin to hold things together.

I was lucky.

The steerer is as they say, "mission critical".
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

ihs0yz
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by ihs0yz

A little update:

I went ahead and bought a fork from Dengfu (FO007) last Friday and it arrived today, really quick! Out of the packaging, my current fork and the new fork are miles apart from each other. The Dengfu forks have your traditional airfoil shape and the steerer tube incorporates a design to "jam" the compression ring (top race) against the top bearing. I'll let the pictures do the talking..

Image

^ Looks straight and bulge free

Image

^ Yep, still straight..

Image

^ The lower end of the steerer tube. A little glossy for some reason.. And the white-ish section has a sanded surface.

Image

^ Spacer test, stops right at the rough section

Image

^ I believe I owe some people how the compression ring and bearing sits on the headtube

Image

^ Bearing, compression ring and dust cap. Flush seat

Image

^ Approximate headtube length, 104mm

Image

^ Bearing and compression ring stops at the rough section as well but as the ruler tells, it's more than enough to get a good seat this time.

Anyway, I didn't push the spacer or bearing past the "rough" section. I was thinking I might smooth out the area and it looks to be roughed out so there's some sort of grip against the bearing to eliminate play.
All looks well! I won't be performing the installation myself, I am not equipped to do so.

The thing about the rough section, I have to say it is clearly a more superior design thought compared to the old fork.

Lastly, the FO007 fork is the same fork that comes with the FM066SL :thumbup:

EDIT: I forgot to ask, does the fork look like it has an integrated crown race? I tried inserting the fork into the frame but it didn't go in from the bottom right away, it sort of stopped at the bearing. I didn't try pushing it as well.

eric
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by eric

That fork needs an crown race. But it's a tight fit. I had to make a tool to press the race down on mine. The tool is thick wall PVC pipe with a cap with a clean square end.

goodboyr
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by goodboyr

Interesting. The last open mold frame I built up came with headset and the crown race that was provided was split. Easy install. I believe it was the same fork.

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