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PostPosted: Fri Aug 04, 2017 2:19 am 
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Location: New Zero Kanada 43° 40' 0" N, 79° 25' 0" W
Seeking advice from Colnago owners.
My headset's wearing out and hard to keep adjusted, and I'm not entirely sure what model it is or where to get one, or whether the HS from a C59 is compatible. Any ideas? Pics for attention.

ImageUntitled by Geoffrey Morgan, on Flickr
ImageUntitled by Geoffrey Morgan, on Flickr


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Posted: Fri Aug 04, 2017 2:19 am 


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PostPosted: Fri Aug 04, 2017 5:20 am 
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Location: eh?
PM sent.

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PostPosted: Fri Aug 04, 2017 11:17 am 
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Location: New Zero Kanada 43° 40' 0" N, 79° 25' 0" W
Mr.Gib wrote:
PM sent.

PM replied to. Thanks!


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PostPosted: Fri Aug 04, 2017 5:00 pm 
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Can't say for sure, but I suspect your headset bearings are fine and the problem is getting the right preload and keeping it there. Have you taken the bearings out and felt them for roughness etc? Even so, if the bearings are shot, you should still be able to keep the headset "adjusted", even though the bearings have turned to a crunchy mess.

There could be several things going on...

1) That headset cover is a mismatch for that headset. It is the short top cover from the Acros headset, which is not what you have installed there. It may be that there is a gap between the compression ring on top of the bearing and the underside of the top cover. If there is a gap, which is impossible to tell from the photo, then you will never get the right preload and it will never be adjusted. You could try shimming it with the shims between the compression ring and the top cover. Keep adding shims until you are sure that there is no gap there and the force from the stem cap bolt is indeed being able to apply some compression on the compression ring and bearing. I did something similar when using a different headset cover in conjunction with my C60 build.

2) The fork bung isn't tight enough and tends to pull up a bit when you tighten the top cap, essentially making it useless for it's purpose.

3) The stem cap is bottoming out on the fork bung before it can apply any preload. There should be enough of a gap between the bottom of the stem cap and the steer tube so this doesn't happen.

4) A crushed steertube. That stem says 9Nm! Holy crap... I've never tightened a stem to that torque on any steertube. If the steertube has been compromised, it would be easy for the stem to slide a bit through use.

It would be good if you could disassemble the whole headset area, and lay everything out in a picture, from top bearing, compression ring, shims (if any), short top cover, spacer, stem, steertube bung, stem cap (lets see the underside). Also, how far above the stem does the steertube extend.

A new headset from and EPS could be obtained directly from Colnago, but I think your main problem is not with the headset itself.

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Colnago C60 - PR99
C59 Five Years Later
My Special Colnago EPQ
Trek Emonda SL Campagnolo SR


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PostPosted: Fri Aug 04, 2017 6:01 pm 
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Location: New Zero Kanada 43° 40' 0" N, 79° 25' 0" W
@Calnago: you legend - that's an exceptional answer. Thank you.
I wanted a lower stem height and got a set of top caps off an EPS owner... and never thought to check whether they were compatible. That's likely the solution. I'll need to mod something with the correct profile and sufficiently low.

BTW: I've never been close to max stem bolt torque!


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PostPosted: Fri Aug 04, 2017 8:29 pm 
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It would be very helpful if you could just pull it all apart and lay out all the parts for a picture. I'd very much like to see the compression bung in the steertube, as well as the stack height of the compression ring on the top bearing and the underside of that top cover.

_________________
Colnago C60 - PR99
C59 Five Years Later
My Special Colnago EPQ
Trek Emonda SL Campagnolo SR


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PostPosted: Fri Aug 04, 2017 11:22 pm 
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Location: New Zero Kanada 43° 40' 0" N, 79° 25' 0" W
Calnago wrote:
It would be very helpful if you could just pull it all apart and lay out all the parts for a picture. I'd very much like to see the compression bung in the steertube, as well as the stack height of the compression ring on the top bearing and the underside of that top cover.


I'll pull it apart when I get home on Sunday so we can close the loop.


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PostPosted: Sat Aug 05, 2017 7:46 pm 
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Location: New Zero Kanada 43° 40' 0" N, 79° 25' 0" W
Closing the loop on this one.
The top cap I was using is the thinnest one seen here:
ImageUntitled by Geoffrey Morgan, on Flickr

It's the middle one with the orange ring in the pic below, and unlike the others is concave on the bottom. The others are flat. I assume the non-flat one is from an Acros headset.

Also in the pic, L-R: two deeper top caps, the thin Acros top cap, the compression ring, and the top bearing.
ImageUntitled by Geoffrey Morgan, on Flickr

If anyone knows where to get a thin, flat-bottomed top cap, I'll be in your debt.

(And, separately, thanks to Mr. Gib for the bearings!)


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PostPosted: Sat Aug 05, 2017 8:10 pm 
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Ok, so it appears as I suspected, the gap between the underside of the Acros top cover and the compression ring is not allowing you to get a proper preload (and you don't need much) on the top bearing and hence makes the whole system feel "unadjusted", because in fact, it is "unadjusted". I also expect the bearings probably feel quite ok, correct?
You can still use that Acros top cover, even though it's not a perfect match for the headset, but you'll need to shim out the gap underneath. Get yourself some metal shims for this purpose, you may need up to 5 or 6 shims to take up the gap, but experiment. The shims are about 0.25mm thick. I think you'll find your problem is solved, unless you've got some issues still with with steertube bung and the stem top cap bottoming out. But you're not showing any of that in the pics so I can't tell. Oh, and is that compression ring beveled to match the bevel in the top bearing? Hope so.
Image

_________________
Colnago C60 - PR99
C59 Five Years Later
My Special Colnago EPQ
Trek Emonda SL Campagnolo SR


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PostPosted: Sat Aug 05, 2017 9:46 pm 
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Location: New Zero Kanada 43° 40' 0" N, 79° 25' 0" W
Calnago wrote:
Oh, and is that compression ring beveled to match the bevel in the top bearing? Hope so.
Image


Indeed it is. Thanks for the tip re: taking up the space.


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PostPosted: Sun Aug 06, 2017 12:17 am 
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Nice custom paint job!

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Colnago C59


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PostPosted: Sun Aug 06, 2017 12:26 am 
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Location: New Zero Kanada 43° 40' 0" N, 79° 25' 0" W
AJS914 wrote:
Nice custom paint job!


I agree! Vélocolour did it about two years ago. Mine's inspired by the Wordperfect team bikes from the early '90s. The Vélocolour people also recently pulled off a very nice Mapei repaint on a C60. Pics on their IG https://www.instagram.com/velocolour/?hl=en.


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PostPosted: Sun Aug 06, 2017 4:37 am 
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That C60 Mapei build was done by David at Nice Bike in Denver. He's a dream bike build specialist if I ever saw one.


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PostPosted: Tue Aug 22, 2017 3:29 pm 
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Location: New Zero Kanada 43° 40' 0" N, 79° 25' 0" W
OK. Shims under the dust cap and a new stem w/ more drop fixed the problem. I now have the bar height matched to my other bike, which has a shorter head tube. (The steerer above the stem is annoying, but cutting it eliminates re-sale opportunity.)
ImageUntitled by Geoffrey Morgan, on Flickr


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Posted: Tue Aug 22, 2017 3:29 pm 


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