paint crack at fork crown - thoughts?

[fiataccompli]

Having just picked up a Lemond Zurich frame from someone here, I remembered that I had saved the fork from a larger Zurich I once owned....so I took it out for a look. I noticed the crack you (I hope) can see in the photo, perpendicular to the fork arms and approximately where the arms are bonded to the crown (presumably Al). I've seen this on a lot of forks of from this time period (it's a circa 2000 Lemond & "air rail" labels) with paint cracks like this. I figured regardless of what anyone says I'm going to sand it a bit and see what I find below the surface, but I was curious if there's some greater wisdom anyone has regarding how worrisome this should be for a fork. In my case, I've pretty much always retired forks that had anything like that because it's not worth the risk. I think I kept this fork more as a holder for the headset that was on it than to use, but I still wonder...I mean, it would really make sense for this to be a pretty standard function of 'normal' forces on a fork considering a single layer of paint over two dissimilar surfaces (metal/CF) bonded together....

http://i256.photobucket.com/albums/hh164/cgfiat/Mobile%20Uploads/C360_2013-12-05-23-11-55-316_zpsf6df317e.jpg (http://s256.photobucket.com/user/cgfiat/media/Mobile%20Uploads/C360_2013-12-05-23-11-55-316_zpsf6df317e.jpg.html)

[Cat3roadracer]

How old is that fork? How important are your teeth ?

[ultraman6970]

IMO that's a crack in the paint. Try to bend it with your arms, if its really cracked will creak like crazy, now if you really want to be sure you have to see whats under the paint, to do that you have to take the paint off using sand paper, the good news is that the color is matcheable. I would sand that if I was you.

Good luck.

[fiataccompli]

I use my teeth almost every day, so they're pretty important!

I think it was original to a 2001 or so bike.

I planned on finding a new or (much) newer fork for the frame this could/would be used on anyway...but when I got it out I started wondering & thus the post.

No visible flexing & absolutely none of those creak (or is it pop?) sounds you get with cracked CF (which, unfortunately I have some of in my workshop)

sanding is no issue because it would be painted anyway if were to be used with the later Lemond frame I had in mind.

and, to reiterate, yeah I like my teeth & bone structure in general where it is presently.

[AgilisMerlin]

i was staring at your stovetop,

1" , got that icon decal

but 11/8" if by the year

what is it, curious



k

[fiataccompli]

that was a trick to divert the eyes of a certain contingent of paceliners! Sorry you fell for it. ha! For the record, the fork is the subject.

well, looks like 1-1/8" but maybe I was wrong?...I'll measure this evening.

None of that has bearing on a perpendicular paint crack and the commonality of such a thing, though.

(and yes, sorry, it is hard to resist being a bit of a smartass)

[guyintense]

I think those forks were steel steertube, aluminium crown, bonded to carbon legs and that crack looks to be right where the alu stops and carbon begins. So, no longer bonded completely? It seems to me if paint is going to crack something underneath is moving.

[cmbicycles]

A lot of Trek's OCLV frames developed paint cracks at the lug joints where the tubes are bonded, just from the tubes flexing and the paint getting older and more brittle. It appears that would be the point where the legs are joined to the fork crown. Sanding it down would be a good way to check for sure, especially if you plan to have it repainted anyway.

[Charles M]

I think those forks were steel steertube, aluminium crown, bonded to carbon legs and that crack looks to be right where the alu stops and carbon begins. So, no longer bonded completely? It seems to me if paint is going to crack something underneath is moving.


This...

[fiataccompli]

wouldn't it move somewhat under normal, "sound" conditions? when you look down riding a nice, vintage fork over some rough road you see this in action...it's not (well, we hope) a prelude to eating pavement, but rather the natural absorption of vibrations in the fork...or so I thought.

thanks all for the feedback (even about the stove). this is really at this point academic since a new fork is less than my medical deductible for 2014 anyway...but, hey, if I end up finding a nice solid structure in this fork it will be interesting at least.