Originally Posted by macca33

I dunno about what others may think, but if you don't know what you're doing with a VERY IMPORTANT part of the bike steering system, then it is probably best left to one who does know.

There is plenty of info on the internet about how to install/adjust the expander/top-cap for the stem - Google is your friend.


From the Cannondale manual:-

The following procedure should only be completed by a professional bike mechanic.

1. Assemble the fork, headset, spacers, and stem without tightening the stem bolts onto the head tube. When
the system is assembled, the carbon steerer tube should be 2-3 mm below the top stem. All spacers must be
located below the stem and within the maximum stack height as shown. No spacers may be used above the stem.

2. Set-up the compression assembly before inserting it. Adjust the length so that the expander is located at
lower stem bolt. The top cap and the expander end provides critical support to the carbon steerer when
tightening the stem bolts. Adjust the length by threading the top cap on the expander parts.

3. When the assembly is the correct length, insert it into the steerer tube. It is designed to fit snugly inside
the steerer. Insert a 5 mm Allen key through the access hole in the TOP CAP and into the EXPANDER BOLT.
Tighten the expanding parts by turning clockwise to 6.8Nm, 5 ftLbs.

4. Now, to set bearing preload, insert a 6mm allen key into the hex shape in the TOP CAP itself. Turn the entire
top cap clockwise to increase preload. Turning it counter-clockwise will decrease the preload. When the
headset preload feels correct, turn the stem to align the handlebar and tighten the stem fork clamp bolts
to the torque specified for the stem. Consult the stem manufacturer’s instructions. The torque values for
components are often marked on the part.

cheers