Weight Weenies

Thx for the replies. To answer some of the questions:

*Scottt Addict, with drop in bearings, 1/ 1/4 lower, 1 1/8 upper, impossible to swap upper and lower.
*Everythings seems to fit in each other without weird feeling, so no 36° vs 45° parts
*No really extra grease on the steer tube where the ring is located. Something to keep in mind next time I take it apart
*The mark from the ring was even around the steerer as far as I remember. Could indeed be due to a little overtorque. I prefer that vs even the slightest play in the headset. But it puts extra stress on the bearings, and maybe also the the steer tube.
*The steer tube is fairly thick and sturdy, front end feels stiff and planted. Makes me think there is no exessive flex in there causing wear.
*Carbon paste between steer tube and stem is the next thing I will do. The area was a little greasy I have to admit, but now, it is completely grease free, cleaned it with a rag soaked with brake cleaner.

Took the bike out for a short spin this afternoon, also in order to re-allign the stem for 100%. HS developped a little play that I took out mid-ride, but back home, it was still fine. Will see how it goes after some 100 or 1000 more miles.

Delorre wrote:

alcatraz wrote:Is it possible your compression plug is overtightened and is giving the steerer enough of a cone shape to kind of guide the stem downwards when it vibrates?

If possible put your compression plug a bit deeper and see if the problem persists.

If you are not experiencing issues then what you have is a nice safety feature. Maybe just leave it as it is...

/a

If so, wouldn't my topcap and 5mm spacer above the stem start to feel loose? But I checked, and the compression plug is only 5nm tight. The expanding part is in the middle of the stem. Will do some riding without the expanding plug (as I do with my Canyons).

But what aboout the compression ring wearing away the stear tube. Seems a real issue to me!

This to me is the most plausible explanation for what's going on. But instead of the compression being overtightened, it may just be in a position that when you tighten the stem lower bolt, it has the same effect of creating a cone shape on the lower edge where the steertube leaves the support of the compression plug. And perhaps the reason your top cap and spacer aren't loosening up in the process is because you overtorqued it to begin with, so the teensy bit of change, enough to cause your bearings to bind, isn't quite enough to loosen off the overtorque to begin with on top.
And I would be very concerned if the steertube has been scored, which could also be the result of overtorquing the whole assembly and squeezing the compression ring into the steertube more than it was designed for.

Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com

Calnago wrote:

Delorre wrote:

alcatraz wrote:Is it possible your compression plug is overtightened and is giving the steerer enough of a cone shape to kind of guide the stem downwards when it vibrates?

If possible put your compression plug a bit deeper and see if the problem persists.

If you are not experiencing issues then what you have is a nice safety feature. Maybe just leave it as it is...

/a

If so, wouldn't my topcap and 5mm spacer above the stem start to feel loose? But I checked, and the compression plug is only 5nm tight. The expanding part is in the middle of the stem. Will do some riding without the expanding plug (as I do with my Canyons).

But what aboout the compression ring wearing away the stear tube. Seems a real issue to me!

This to me is the most plausible explanation for what's going on. But instead of the compression being overtightened, it may just be in a position that when you tighten the stem lower bolt, it has the same effect of creating a cone shape on the lower edge where the steertube leaves the support of the compression plug. And perhaps the reason your top cap and spacer aren't loosening up in the process is because you overtorqued it to begin with, so the teensy bit of change, enough to cause your bearings to bind, isn't quite enough to loosen off the overtorque to begin with on top.
And I would be very concerned if the steertube has been scored, which could also be the result of overtorquing the whole assembly and squeezing the compression ring into the steertube more than it was designed for.

Makes sense! For the pease of mind, I put the expander plug back in place, as low as possible, ending 5 mm above the bottom of the stem. The plug is only 2,5 cm tall, leaving a good cm between top of stem and top of expander. I also took my time to preload the HS just as tight, as there is no play anymore, going back and forth a few times, just like with a Campy Bora hub f.ex. Will see how it goes this way, will keep you updated on the results.

Years and years ago I had a custom frame that used a Columbus integrated headset design. This was like a drop-in style integrated HS but it had "cups" that were specific to the frame. I was using a Columbus Super Muscle fork initially and I noticed a similar thing, some marks on the steerer from the split compression ring that presses down on the top bearing. The mark was uniform around the steerer and the same height as the ring itself. Being concerned at the time, I swapped the fork to a Reynolds Ouzo Pro and re-installed everything but also worked over the compression ring with some fine grit sandpaper to make sure there were no sharp edges. Fast forward a couple of months and again after pulling it apart I noticed a similar mark from the compression ring. My conclusion was that this had to be from fretting, microscopic movements causing the ring to move on the fork The surface didn't look like it was indented at all but rather "buffed" smooth. Just for sanity's sake I used some 600-grit paper and super-lightly sanded the mark out. I could not see any sign of cutting or notching, so I just bolted it up and and rode it with no further problems, until the frame was damaged in a crash a couple years later.

For the OP, have a real careful look at the steerer and the mark, there may not be any damage here other than cosmetic.

Try a trick I figured out 15 years ago with my first carbon steerer on a Ti frame that refused to stay in place: put a medium hard (like 75 durometer Viton) 1/8" or 3/32" (3mm or 2mm) o-ring between the top of your headset and the bottom spacer (or stem if you don't use a spacer). Get one with ID a little smaller than your steerer OD so if fits snug. When clamping the stem, squish the o-ring about .75 - .5mm and lock it there. This allows a bit of give on the upper bearing during impacts, vibration, temp changes, etc., but with zero play in the bearings. You can use more common Buna-N o-ring, but Viton will last many times longer in the elements. If your stem is too narrowly tapered at the bottom, a spacer may be necessary to keep the o-ring from squishing out instead of down.
Even with low torque and without friction compound holding the stem, it won't move for years, which also means you can use low enough torque that the bars can twist instead of break in a crash. Also the bearings will last much longer since the consistent preload will prevent any bearing slap due to some clearance that is necessary with a rigid clamped bearing. Bumpy roads and brake knocking will be silenced like you didn't think possible.
I've since discovered Extralite designs their headsets with an o-ring to nest in the top bearing cap now (in addition to making the lightest and lowest stack height headsets!) - all headsets should come this way! Such an easy and cheap solution - try it and never futz with your headset again.

I had a very similar issue several years ago on my preowned Trek 5900. I was always having to readjust the headset as it would tighten up on me after a couple hundred miles. After searching online for similar problems I found out there was a recall on the Trek fork/headset. The problem was with the proprietary bearings. They were not seating properly on the races. I ended up with a new fork and bearings/races in standard sizing. I bet it's something similar. Just have the fork/headset checked for allignment.