Split Crown Race Issue

[liray]

So long story short, I have a Chinese carbon fork, and the crown race (which is split) is not sitting flush against the fork crown. I'm mentioning that it is a Chinese fork because, needless to say, there are QC issues with it.

Originally, there were two little "tabs" protruding from the fork crown, which I had sanded down to create a (somewhat) flat surface for the crown race to sit on.

However, even after this process, the split crown race does not seem to be sitting flush. At first, it seemed like a big gap, but I realized (much later) that the crown race bottom face is also slightly tapered like the topside. Now looking at it, there seems to be a (slightly smaller) gap between the fork crown and crown race.

Now, I know that it "should" sit completely flush. Online, however, some people with similar forks have said that a 0.5-1mm gap is ok.
I took the best picture that I could, and I need you all to tell me what I should do.
Note: I finished the setup with the crown race as pictured, and there didn't seem to be any play in the headset when I applied the front brake and wiggled...

Also, just so you have an idea, the split crown race hasn't "snapped" into place at the spot. It simply refuses to go down further, and spins freely at that position. I tried using a flathead to pry the split further but it didn't seem to allow it to sit any lower.

:help:
http://s201.photobucket.com/user/liray/media/IMG_15801.jpg.html

[KidWok]

Could it be that you aren't using the right HS spec? If you're talking "Chinese", is it an open mould frameset that might be using an existing standard? Or a copy of an existing brand that uses a proprietary spec? We're those two tabs you sanded down indicative of a special headset or did they just look like something from a mould void?

Tai

[Peter B]

I'm curious what fork this is, or what frame it came with. PM if you don't want to be public.

I have one that appears to be strikingly similar and while I did not notice or measure a gap as you indicate, I put it all together and it functions flawlessly.

[liray]

I don't mind saying, but I only just realized it may help out solving the issue.
It's the new Chinese replica of a Pinarello Dogma 65.1.

And yes, the two "tabs" were like something from a mould void because they were deformed looking and not something that would "notch" into a special headset.

All I know is that it is a tapered fork, and the headset seems to be a copy of what they would actually use on a Pinarello.

[Peter B]

Sorry, can't speak directly to your issue. Mine is an Asian-made tapered fork of a different brand. Split-crown race IIRC but works fine in the machined headtube w/ drop-in headset.

Hope you can get yours sorted.

[ultraman6970]

You have paint in there apparently, sand paper is very useful for those things.

Cut tiny bits with a knife and then finish with sand paper. Second option is to sand the crown race.

[liray]

You have paint in there apparently, sand paper is very useful for those things.

Cut tiny bits with a knife and then finish with sand paper. Second option is to sand the crown race.

Hmmm. That seemed to be what I was thinking. So my question is it HAS to sit perfectly flush then?

Also, both of my LBS were freaked out when I asked me to sand the tabs down for me. One refused to do it, and the second guy took some persuasion.

[ultraman6970]

The issue with a LBS is that if the fork fail you can sue them, so doubt a LBS will do it.

Is super simple to know if needs to be flushed tho...

just put the fork in the frame and see how close the front tube from the crown fork is, if its too far, like just the distance you are having the problem with then is clear what you have to do.

If the frame and the fork are like right, almost touching to each other then dont do anything, maybe they figured it out a way to fix a design problem and thats why you have those tabs in there, so the front tube and the fork dont touch to each other.

[liray]

Its relatively safe to sand the fork though to get it to fit right?

Because the way the LBS was describing it... if they even placed it near sandpaper the whole thing would explode.

[ultraman6970]

IMO is safe if you do it carefully, but is just my opinion. Its your call.

[dave thompson]

With Chinese "replicas" there are many QC issues with no definitive fixes. Each is different and more often require experimentation and skills to fix.

If I were an LBS I would do the same as the one you went to; nothing.

[pdmtong]

hey, you got what you paid for....fixable but you need to do yourself. If I am the LBS I run not walk away....

[liray]

I'll give it a shot sometime this week then and see how it turns out then

[ultraman6970]

As i said before, lbs wont touch it because it means liability. Use sand paper carefully doesn't have need you to be Einstein but if by any circumstances the fork fails even thought wasn't because of what the lbs did the person the client will go with the hospital bill is the lbs, so doesn't surprise me that they said that about carbon exploding anyways.

[Peter P.]

The gap looks symmetrical so even though the ring isn't flush, it's probably perpendicular to the steerer axis, which is all you need.

I wouldn't worry about it. Ride the fork as-is and see if riding wears out the carbon lip and forces the crown race flush. If there's no binding in the fork rotation and the fork doesn't regularly come out of adjustment, then the lip is strong enough to support the forces upon it. Put an o-ring under the split crown ring to fill the gap just for aesthetics, if you must.

Next thing I'd try, which is probably heresy, is try to convince a bike shop to use their crown race cutting tool to mill the lip away.

Last option, just replace the fork.

It's the stingy man that pays the most.

[oldpotatoe]

The gap looks symmetrical so even though the ring isn't flush, it's probably perpendicular to the steerer axis, which is all you need.

I wouldn't worry about it. Ride the fork as-is and see if riding wears out the carbon lip and forces the crown race flush. If there's no binding in the fork rotation and the fork doesn't regularly come out of adjustment, then the lip is strong enough to support the forces upon it. Put an o-ring under the split crown ring to fill the gap just for aesthetics, if you must.

Next thing I'd try, which is probably heresy, is try to convince a bike shop to use their crown race cutting tool to mill the lip away.

Last option, just replace the fork.

It's the stingy man that pays the most.

That is really a bad idea, IMHO.

[ultraman6970]

I would not use a tool like that in a carbon fork and I'm kind'a radical with fixes sometimes.

[cmg]

the ring looks level across the bottom of the fork. Either use it like that, which will give you more clearance between the bottom of the headtube and the fork crown or grind the underside of the split crown race so that it will clear the little lip of the fork steerer tube interface.

[oldpotatoe]

So long story short, I have a Chinese carbon fork, and the crown race (which is split) is not sitting flush against the fork crown. I'm mentioning that it is a Chinese fork because, needless to say, there are QC issues with it.

Originally, there were two little "tabs" protruding from the fork crown, which I had sanded down to create a (somewhat) flat surface for the crown race to sit on.

However, even after this process, the split crown race does not seem to be sitting flush. At first, it seemed like a big gap, but I realized (much later) that the crown race bottom face is also slightly tapered like the topside. Now looking at it, there seems to be a (slightly smaller) gap between the fork crown and crown race.

Now, I know that it "should" sit completely flush. Online, however, some people with similar forks have said that a 0.5-1mm gap is ok.
I took the best picture that I could, and I need you all to tell me what I should do.
Note: I finished the setup with the crown race as pictured, and there didn't seem to be any play in the headset when I applied the front brake and wiggled...

Also, just so you have an idea, the split crown race hasn't "snapped" into place at the spot. It simply refuses to go down further, and spins freely at that position. I tried using a flathead to pry the split further but it didn't seem to allow it to sit any lower.

:help:
http://s201.photobucket.com/user/liray/media/IMG_15801.jpg.html

Ya sure you need the fork crown race? 'Looks' came with one but was never used on their forks, the fork beveled base ran against the lower cart bearing.

[liray]

I'm pretty sure I need the crown race because the surface simply wasn't near being flat enough to run the bearings right on top.

Its interesting to note that two people have said that I can just run the race on the "lip". If all else fails, I think I feel a bit better about its current state. However, I will still attempt to remove that extra lip which seems to be caused by excess paint.

[Dave]

The problem appears to be nothing more than some buildup of paint and/or resin in the corner where the steering tube and fork crown intersect.

Another option is to check the size of the chamfer on the crown race. If there is little or no chamfer on the bottom the of race, on the ID, then that could be increased and eliminate the interference.

A little careful scraping with an Xacto knife might also work to remove the offending material from the inside corner.

[atl001]

You might consider a different race or headset. If you find a headset race with enough chamfer on the inner diameter, perfect. If I were to run the race on the "lip" without modification, I think I would feel more comfortable using a non-split race. The split race might deform and ruin the headset anyway.

[Cat3roadracer]

Abort the whole project. Your teeth are worth much more than a knock off fork.

[csm]

"But it was a heckuva deal!"


Sent from my iPad using Tapatalk HD

[liray]

Yeah, I'm not turning this thread into a debate.

Abort the whole project. Your teeth are worth much more than a knock off fork.

[soulspinner]

The gap looks symmetrical so even though the ring isn't flush, it's probably perpendicular to the steerer axis, which is all you need.

I wouldn't worry about it. Ride the fork as-is and see if riding wears out the carbon lip and forces the crown race flush. If there's no binding in the fork rotation and the fork doesn't regularly come out of adjustment, then the lip is strong enough to support the forces upon it. Put an o-ring under the split crown ring to fill the gap just for aesthetics, if you must.

Next thing I'd try, which is probably heresy, is try to convince a bike shop to use their crown race cutting tool to mill the lip away.

Last option, just replace the fork.

It's the stingy man that pays the most.

Ride it