Threadless Headset Tightening Question
 

Pedal Force QS2 carbon frame
Pedal Force carbon fork w/ carbon steerer
FSA CE integrated headset
"Spreading clamp" type headset cap

I'm having a little trouble getting a tight fit on the headset and could use some advice. I'm not working with a starnut type cap that I guess would let me tighten down to pull the fork in tight to the head tube, so I have to put a load on the bearings while I tighten the nuts somehow. How do you do this?, and, any idea on what a safe torque is for the stem and cap on all this carbon stuff? Thanks

This is a compression plug cap, like the Weyless models that Nashbar sells. It expands outward inside the steerer tube. I've never used the starnut type but I understand how tightening the nut on them pulls the whole business together to preload the bearings. This does'nt, it just tightens it, the steerer and stem together but does nothing to pull up to preload the bearings.

First I just pushed down on the cap with most of my 170 lbs. while tightening it and the stem bolts. It was ok for a while but it loosened up on it's own. The headset clatters over bumps now. I'm asking if there's a better way.

If the expander's bolt is pulling the steerer and stem together either your steerer is a few mm too long or you need a small spacer on top of the stem.

The expander should act just like a starnut and let the adjusting bolt pull the steerer up inside the stem (you did loosen the stem clamp bolts completely didn't you?) until the headset is preloaded properly. If the steerer is so long it comes up flush against the stem's top before proper adjustment is reached you will never get it adjusted properly.

The usual recommendation is that the steerer should be 2 to 3 mm BELOW the top of the stem (or below the top of a spacer above the stem) when proper adjustment is achieved.

+1 Hillrider

I have a Profile SBC fork(carbon steerer) that came with thier Gap cap, a compression plug supposedly designed to work with carbon. Ended up driving a star nut into it to get the adjustment to hold since everything else was correct. Follow HR's post on steerer gap first. As for torque, consult the manual or call tech service. I want to say that for Profile their spec was 65-85in.lbs. around the carbon steerer. Yes, they advize against a starnut in a carbon steerer(warranty void) but the composite plug was slipping constantly so... No sign of trouble after a season.

Well explained here: http://www.parktool.com/repair/readhowto.asp?id=65

Start a little over half way down after they get done messing with the cups and installing the star nut. Your compression plug works exactly like the star nut, just better. The thing's whole job is to push down on the stem and pull up on the fork to allow you to load the bearings. This is pretty much a "somewhere near finger tight" adjustment, not a torque wrench thing. Manufacturer should have torque spec on the stem bolts. Once the stem is screwed down, you could pull the whole cap/expander/star nut mess out if you really wanted to, it's the stem that's doing the work.

As a side note to all of this, I just got an Easton EC90 SLX all carbon fork for a new bike I'm building up. The Easton came with a very clever gadget called an "EA-HSA Headset Adjuster" that eliminates the need for star nuts, expander plugs and the steerer cap and bolt. It weighs only 11 gms, which is less than a top cap, bolt and starnut and much less than any expander plug

It's two thin rings with opposing ramps on one face of each and a small bolt that rotates the two rings relative to each other. You put the HSA rings on the steerer like a thin spacer under the stem and/or any additional spacers. You take most of the slack out of the steerer then center and tighten the stem clamp bolts. Finally you adjust the headset by backing out the small bolt in the adjuster rings. This makes one ring climb up the ramps on the other, rather like an ajustable height spacer, and sets the headset clearance.

All you need for the steerer top is a plastic plug similar to a handle bar plug and Easton provides one of these too.

BTW, the fork is scary light! Easton claims 290 grams with an uncut steerer and mine weighs just what they said.

Is this similar to the Ringo-Starr?

I don't know. Does the description sound similar? Easton doesn't say the thing is proprietary to them but it has their part name on the package.

You can just as well use a woodworking clamp and squeeze the bottom of the fork crown and the top of the stem before tightening the stem pinch bolts...:D
Of course, aligning the stem to the front wheel would be a bit of a hassle.....

Ignoring the obvious attempt at humor (a poor attempt I might add :rolleyes: ), this works only if the steerer is short enough.

Well, originally I thought that when I tighten the cap bolt, the expander would only expand outwards. But now I see (I think), that it also draws upwards a little bit at the same time. If that's so, it's the way to preload the bearings if the stem bolts are loose at that time. True? What I was doing was alternately tightening the stem and cap bolts a little at a time so as not to stress the carbon steerer either from the inside or outside. So, leave the stem loose while tightening the cap bolt, then tighten the stem bolts?

My steerer is 1/8" below the top of the stem, so I'm ok in that regard.

yes and yes

The ONLY way to set the headset adjustment is if the stem clamp bolts are loose. What you did is a common mistake but, again, the stem clamp bolts MUST be loose to adjust a headset with either a star nut or an expander plug.