oldroadie48

One again I need everyone's help. I have a Bianchi Infinito CV. The headset is held together with an internal bolt that is at the top of the headset assembly. This bolt is visible inside a small tube at the top of the assembly. This also holds the fork on. There is nothing else in the top of the headset assembly and the small tube is not threaded. So how does a top cap fasten down? Am I missing a compression plug or star nut? If any Infinito CV owners can help me I would be appreciative as I am down from riding until I get this fixed.

gsa103

Can you take a picture?

I've got an Infinito (non-CV), if I recall, the top cap itself is designed for 6mm allen wrench. The compression adjustment is via a 4 or 5mm allen wrench which you insert through the 6mm opening in the top cap.

rm -rf

My Infinito steerer plug looks like this. It's expanded against the inside of the steerer tube by a 4mm hex socket down in the center tube. The top cap screws onto the outside threads. It's a little different design than other bikes I've seen, and fairly confusing if you are used to the typical plug with a long center bolt up through the cap.

To use this expander, you'll need the non-standard threaded top cap that came on the Infinito. See a photo of the whole assembly for sale here (it's an FSA cap and plug.)

If you loosen the plug completely, it'll fall down to the bottom of the steerer tube. (from experience!) Turn the bike upside down and shake it out if needed.

Do you know how threadless stems are adjusted? The two stem bolts are loosened, the plug is set to the correct height, the top cap is tightened just enough to take the play out of the bearings, then the stem bolts are tightened to lock it all together. (The top of the stem or the top spacer need to be above the steer tube so the top cap can press down on the stem-spacers and pull up on the steerer.)

To install a plug, I thread it to the top cap with a couple of turns, lower the whole thing onto the steerer, then tighten the expander plug with a 4mm wrench. Now the cap can be turned with a 6mm wrench to adjust the play.

The black plastic plug seems to be the cause of rattling for some Infinito riders. See this thread.

oldroadie48

So the compression plug fits over or just above the small tube at the top of the headset? I can't send a picture as the frame is at the bike shop.

rm -rf

The compression plug is the aluminum assembly in the photo. The black plastic cylinder is probably supposed to be reinforcement inside the steerer, but it fits too loose to have much effect.

The left side of the aluminum piece is the part you see if you remove the top cap, of course. (But if the black cylinder is also in there, it's level with the top of the threaded aluminum tube, which makes it all even more confusing.)

z8ee

This thread was a huge help to me. I loosened the compression plug too much, like RM -RF, on my Bianchi Intenso, and couldn't figure out what happened. Looking down into the fork/steering tube showed it perfectly centered as if it was part of the fork tube. Watching YouTube vids was of no help as they showed other style assemblies. I took the fork off and inverting it, only the black spacer/damper fell out, but not the aluminum compression plug. Even rapping the steering tube on the garage floor wouldn't dislodge it. (Scary to do that to carbon fiber tube.) Finally, using a long screw driver, I wiggled the compression plug out and understood how it works. THANKS!