jonthebiker

Yes. I think thats my problem. As of now with my previous cut on the tube when everything is installed the top of the steerer tube itself is about two millimeters below the top of the stem. Thus the installed compression plug is falling about even with the top of the stem. I may have misread that before cutting. I think I probably read that the gap between the steer tube and the top of the stem should be 2 mm. Instead, it should be interpreted that the top of the installed compression plug should fall two mm below the top of the stem. I did not take into account the width of the thin plate at the top of the compression plug which is actually about 2 mm wide.

as per the instructions from Ritchey that I posted up thread.

Damn, it pays to read and interpret properly !
The position of the top of the
compression device should not be
deeper than 3mm from the top of the
stem. It is preferred to leave excess
lenght on the steerer tube and add a
spacer above the stem.

jonthebiker

Was cutting off that one extra millimeter a pain in the arse ? Or did it go smoothly ?

dr_lha

It was not a pain in the arse at all, the cutting guide made it easy.

jonthebiker

Excellent. Then it sounds likemy situation is quite salvageable. I will start conservatively and cut another millimeter off. If that works, good. If not I'll cut another millimeter off and I should be fine as I'm pretty sure I'm no further off than that presently. Thanks for the help.

fietsbob

put a Spacer on top if the stem.

jonthebiker

That probably would work but I'm not sure I like that idea as much because there is no steer tube there to support it with the setup I currently have. As a result the only thing supporting the spacer and keeping it from sliding around is the force of the top cap bolt. But the top cap bolt is not supposed to be tightened too strongly, just enough to preload the bearings without causing binding in the steering. That is usually around 5 or 6 Nm of torque. I would feel more comfortable following that solution if I had left the cut steerer a few millimeters above the top of the stem. But my cut steerer is already a few mm below the top of the stem.

rm -rf

I see you've already trimmed it--good.
But it's okay to have a spacer above the stem. You have this type of compression plug that has a lip that sits on the top of the steerer--it's the black ring at the top in the photo.

There are other plugs that fit completely into the steerer. Those are a little more complicated to install, so that they don't fall all the way to the bottom of the steerer. (attach the top cap screwed in part way, lower the plug into the steerer, tighten the plug through the top cap. Now adjust the preload as usual.)

I haven't cut my steerer to it's final size, so I'm using a 10mm and a 2.5mm spacer above the stem. I'll eventually cut it to just use a 5 mm spacer, and the steerer itself will show a couple of mm above the stem.

jonthebiker

Thanks Rm. Is your option good though with respect to the location and height of the compression plug in the steerer. It seems as though Ritchey has designed the compression plug to be placed ideally so that its pressure opposes the pressure of the stem clamping thus preventing deformation of the steerer tube due to the clamping force of the stem. With your setup shown the compression plug appears to be primarily above the stem rather than directly inside of the stem clamp area. Is that safe ?

rm -rf

Oh, I see how you had to trim it, since you didn't have any steerer showing above the stem. Good.

I think that 5 nm of preload is way too high. Are you confusing the two pinch bolts torque with the center cap?

It does seem to depend on the bike. I've had bikes that only needed extremely light finger pressure on the hex wrench to set the preload--just barely tightened. And others that needed more pressure. But nothing like 5 nm.

I stand over the bike with the top cap loose and the two pinch bolts loose, and rock the bike front to back by holding the handlebars. I can feel and hear the "click" or "clunk" from the loose bearings. So I tighten the top cap a little more, and test again, until the clunk goes away. I'll loosen it slightly and see if it's still good--if the clunk comes back, I'll retighten that little bit again.


Yes, you want the plug to be down where the stem clamps the steerer tube.

My plug is pretty tall. It extends down past the top pinch bolt. So I think it's completely safe. I don't overtighten the pinch bolts on the stem, and don't even go to the max torque printed on the stem. I just checked--both pinch bolts are right at 4 nm. ( I've tested by straddling the front wheel and trying to twist the bars off center, with some reasonable pulling on the bars, not a huge max effort. They don't move.)

My other bike has a different style compression plug, just a 4mm width that contacts the steerer tube, with the rest of the plug narrower. It actually surprised me how small the contact area is. Carbon steerer tubes are pretty sturdy.

jonthebiker

I think I solved my problem. I came home and looked at my setup. The top plate of the compression plug when tightened in is flush with the top of the stem ( see photos below ). This was not allowing the top cap to do its job as it was bottoming out and could not be tightened properly as there was not enough gap between the top cap and the top of the compression plug. So as a previous gentleman suggested, I stuck a five mm spacer on top of the stem, inserted the top cap and voila, it works well, everything feels solid with no clunking. I like the fact that the plug is where it's supposed to be, right in line with the stem bolt. It meets Ritchey's spec of being no more than 3 mm beneath the top of the stem, and it seems quite stable. Likely even more so when I tighten the stem bolts. I like the fact that this option does not require me to cut the steer tube again.
I don't know ultimately what to think of Ritchey's design theory here. I see why he wants the plug where it is by design but the type of plug that drops in and whose lip catches the top of the steer tube definitely requires one to think more clearly about where the top of the steer tube needs to be once cut. With a drop in plug that could be located in the tube a bit further down one need not be so careful where the top of the steer tube is located as the compression plug could be moved a bit accordingly.

rmfnla

RubeRad

Not flush. Flush = no compression. You need the compression plug to have a little bit of space below it to be able to push down on the stack of stem+spacers. It might also be the case that your headset is not yet completely pressed in and riding will cause a little bit of settling.

Now to answer your question, is it ok to add another couple mm of spacer to overcome your problem (I don't know why so many others are having trouble understanding your question), unfortunately I cannot answer authoritatively, but in my opinion another 5mm spacer should pose no problem. But then again, I'm not a by-the-book kind of guy. I tend to see hard numbers like that as having been set very conservatively for legal CYA reasons.