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#1
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Perpetually loosening threadless headset...
I have a Santa Cruz Blur mountain bike with a Chris King threadless
headset. In order to keep the headset from creaking due to fore/aft movement, I have to retighten it every ~10 hours of ride time. I am confident that the fore/aft movement is from the headset and not the fork bushings (Rock Shox Reba fork w/alloy steerer) because the noise disappears after retightening. The top cap has ample clearance over the top of the steerer so its not bottoming, and the stem has plenty of clamp area, although I run the stem with no spacers above, so the clamp extends over the top of the steerer. I bought the bike used in pristine condition so I very much doubt there's any crash damage. The headset cups appear to be seated properly. The only cause I can think of is a poorly faced headtube or misaligned crown race. I was told that a good test is to disconnect the front brake, remove the handlebars, and rotate the stem 360 degrees, feeling for variations in resistance due to misalignment. I did this and could not detect any variation. Can anyone advise as to whether the test outlined above is a reliable way to check for misalignment? Any other hints for troubleshooting this? I'd prefer to exhaust all my other options before shelling out the bucks to have the headtube re-faced. |
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#2
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Perpetually loosening threadless headset...
Dave wrote:
I have a Santa Cruz Blur mountain bike with a Chris King threadless headset. In order to keep the headset from creaking due to fore/aft movement, I have to retighten it every ~10 hours of ride time. I am confident that the fore/aft movement is from the headset and not the fork bushings (Rock Shox Reba fork w/alloy steerer) because the noise disappears after retightening. The top cap has ample clearance over the top of the steerer so its not bottoming, and the stem has plenty of clamp area, although I run the stem with no spacers above, so the clamp extends over the top of the steerer. I bought the bike used in pristine condition so I very much doubt there's any crash damage. The headset cups appear to be seated properly. The only cause I can think of is a poorly faced headtube or misaligned crown race. I was told that a good test is to disconnect the front brake, remove the handlebars, and rotate the stem 360 degrees, feeling for variations in resistance due to misalignment. I did this and could not detect any variation. Can anyone advise as to whether the test outlined above is a reliable way to check for misalignment? Any other hints for troubleshooting this? I'd prefer to exhaust all my other options before shelling out the bucks to have the headtube re-faced. Try wrapping a bit of plumber's tape around the base of the steer tube, under the race. (Over it is OK, too.) Sometimes the looseness originates down there, though it's "felt" at the headset. Billl "Master Mech Mickey...not" S. |
#3
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Perpetually loosening threadless headset...
Dave schreef:
I have a Santa Cruz Blur mountain bike with a Chris King threadless headset. In order to keep the headset from creaking due to fore/aft movement, I have to retighten it every ~10 hours of ride time. I am confident that the fore/aft movement is from the headset and not the fork bushings (Rock Shox Reba fork w/alloy steerer) because the noise disappears after retightening. The top cap has ample clearance over the top of the steerer so its not bottoming, and the stem has plenty of clamp area, although I run the stem with no spacers above, so the clamp extends over the top of the steerer. I bought the bike used in pristine condition so I very much doubt there's any crash damage. The headset cups appear to be seated properly. The only cause I can think of is a poorly faced headtube or misaligned crown race. I was told that a good test is to disconnect the front brake, remove the handlebars, and rotate the stem 360 degrees, feeling for variations in resistance due to misalignment. I did this and could not detect any variation. Can anyone advise as to whether the test outlined above is a reliable way to check for misalignment? Any other hints for troubleshooting this? I'd prefer to exhaust all my other options before shelling out the bucks to have the headtube re-faced. A Chris King headset is very picky in regard to the squarness of everything including the stem. Did you face your stem, most people don't? Lou |
#4
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Perpetually loosening threadless headset...
Dave Benoff wrote:
I have a Santa Cruz Blur mountain bike with a Chris King threadless headset. In order to keep the headset from creaking due to fore/aft movement, I have to re-tighten it every ~10 hours of ride time. I am confident that the fore/aft movement is from the headset and not the fork bushings (Rock Shox Reba fork w/alloy steerer) because the noise disappears after re-tightening. The top cap has ample clearance over the top of the steerer so its not bottoming, and the stem has plenty of clamp area, although I run the stem with no spacers above, so the clamp extends over the top of the steerer. I bought the bike used in pristine condition so I very much doubt there's any crash damage. The headset cups appear to be seated properly. The only cause I can think of is a poorly faced headtube or misaligned crown race. I was told that a good test is to disconnect the front brake, remove the handlebars, and rotate the stem 360 degrees, feeling for variations in resistance due to misalignment. I did this and could not detect any variation. Can anyone advise as to whether the test outlined above is a reliable way to check for misalignment? Any other hints for troubleshooting this? If it is loosening, then the stem clamp, that holds the whole thing together and in the same place, must not be clamping properly. Is it possible that the clamp is bottoming... that there is no gap in the clamp slot when tightened? I'd prefer to exhaust all my other options before shelling out the bucks to have the headtube re-faced. The way you report it, something is loose and moving. Jobst Brandt |
#5
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Perpetually loosening threadless headset...
On 7 Nov, 18:22, Dave wrote:
I'd prefer to exhaust all my other options before shelling out the bucks to have the headtube re-faced. Just curious. How much, over the Atlantic Pond, would a mechanic charge for disassembling, facing and reassembling the set? Sergio Pisa |
#6
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Perpetually loosening threadless headset...
On Nov 7, 10:10*am, wrote:
If it is loosening, then the stem clamp, that holds the whole thing together and in the same place, must not be clamping properly. *Is it possible that the clamp is bottoming... The clamp is not bottoming, and the behavior has occurred while using a different stem as well. My understanding is that the fore-aft motion of the steerer will eventually cause any stem to migrate upward, no matter how well fastened. I have no idea whether this is true, but it seems to be the conventional wisdom, and certainly seems to be confirmed by my experience. |
#7
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Perpetually loosening threadless headset...
On Nov 7, 10:50*am, sergio wrote:
On 7 Nov, 18:22, Dave wrote: I'd prefer to exhaust all my other options before shelling out the bucks to have the headtube re-faced. Just curious. How much, over the Atlantic Pond, would a mechanic charge for disassembling, facing and reassembling the set? Sergio Pisa Probably upwards of $100USD here in Los Angeles (probably cheaper in other regions of the US). Many shops here don't even have the tools or a mechanic skilled enough to do the work. |
#8
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Perpetually loosening threadless headset...
On Nov 7, 12:22*pm, Dave wrote:
I have a Santa Cruz Blur mountain bike with a Chris King threadless headset. *In order to keep the headset from creaking due to fore/aft movement, I have to retighten it every ~10 hours of ride time. *I am confident that the fore/aft movement is from the headset and not the fork bushings (Rock Shox Reba fork w/alloy steerer) because the noise disappears after retightening. *The top cap has ample clearance over the top of the steerer so its not bottoming, and the stem has plenty of clamp area, although I run the stem with no spacers above, so the clamp extends over the top of the steerer. *I bought the bike used in pristine condition so I very much doubt there's any crash damage. The headset cups appear to be seated properly. *The only cause I can think of is a poorly faced headtube or misaligned crown race. *I was told that a good test is to disconnect the front brake, remove the handlebars, and rotate the stem 360 degrees, feeling for variations in resistance due to misalignment. *I did this and could not detect any variation. Can anyone advise as to whether the test outlined above is a reliable way to check for misalignment? *Any other hints for troubleshooting this? I'd prefer to exhaust all my other options before shelling out the bucks to have the headtube re-faced. I've experienced something similar twice. Doesn't seem like either is the case for you, but I’ll relate the causes anyway. The first time, it was a new headset that didn't have the cups pressed into the frame tight enough. After a couple rounds of tightening the stem, I really clamped the cups in there and the issue never came back. The second was recent. On a used bike, the steerer was too long for the setup. It looked like there was ample clearance between the top of the steerer and the cap, but was actually close enough to the cap that the tightening of the star nut bottomed out the steerer to the cap, even though there was clearance when not torqued down on the star nut. I ended up trimming the steerer, but a spacer would have fixed it as well. How much room is there between the top of the steerer and the top of the stem when inspecting? Are you 100% sure there is no way that it is bottoming out? You could check by tightening everything up as normal, then removing the cap. If there isn’t still some clearance at the top of the steerer after you’ve torqued the cap against the star and then tightened the stem, that could be your culprit. |
#9
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Perpetually loosening threadless headset...
On Nov 7, 9:22*am, Dave wrote:
I have a Santa Cruz Blur mountain bike with a Chris King threadless headset. *In order to keep the headset from creaking due to fore/aft movement, I have to retighten it every ~10 hours of ride time. Maybe a long shot, but have you checked that the headtube is round and not ovalized? |
#10
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Perpetually loosening threadless headset...
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