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Old 09-17-10, 10:42 PM   #1
boro
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Gah... FSA headset bearing cap crooked

Background: I bought a 'Pake C'mute' frameset a few months ago and started putting it together after moving. I had enough tools to put most things together, but nothing to install a (threadless) headset, so I let a local shop do the whole shebang (press the cups, cut the steerer) and assembled the bike.

After riding for a day or two, the headset felt a little loose, so I took to the wonderful folks at a bike co-op on the way home and we tightened up the headset. Everything great, right?

Well today I noticed that there was a significant gap between the bearing cap and the bearing cup I did some searching on here and elsewhere online and found that other people had noticed some peculiarities with their FSA headsets, but I wanted to investigate further...

I pulled it apart and noticed that the split ring doesn't want to sit in flush... one edge wants to sit higher than the other. When the bearing cap goes down, it does the same thing. The cap toward the frame side (back of the bike) has ~1.0mm of gap between itself at the cup, while the front side has 0.55mm of gap.

What could be the problem? Steerer isn't bent (problem remains the same as the steerer is turned), so I'm guessing since the cup looks fully seated that the head tube wasn't square to begin with, or it was faced improperly.

Last edited by boro; 09-18-10 at 10:28 AM. Reason: further investigation...
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Old 09-18-10, 01:01 PM   #2
boro
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I'll try to get a picture so one can visualize what I'm talking about.

Or, if this is a stupid question, someone can tell me that, too.


Last edited by boro; 09-18-10 at 01:35 PM. Reason: picture
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Old 09-18-10, 01:51 PM   #3
boro
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http://www.bikeradar.com/forum/viewtopic.php?p=16133574

Similar problem, methinks
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Old 09-18-10, 02:09 PM   #4
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looks fine to me. only .45mm out of paralell from your measurements. the gap needs to be their or else it will rub on the "cup". you can try greasing the split compression wedge but i dont think it will make a difference.
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Old 09-18-10, 03:18 PM   #5
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Let's also make sure that the steerer was cut properly, the cut is perpendicular to the steertube and that it's not uneven pressure from the top cap that is causing this.
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Old 09-18-10, 03:24 PM   #6
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crooked

stem and, or spacers are not machined parallel.
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Old 09-18-10, 04:44 PM   #7
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Maybe the frame headset area needs to be refaced also, have u checked this? Some bikes come pretty weird from factory.
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Old 09-19-10, 09:13 AM   #8
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So I disassembled it again, drove the compression ring (gently) in so it was sitting as flush as I could get it, but it still seemed to sit in a weird way with just the bearing cap on top. Was going to index the spacer stack, but I flipped it around and found the tolerances much closer, so I think you guys were right. It's sitting around .55 all the way around now.
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