Hello,

I have recently built a road bike. However, after finishing the build, I found that the Top Cap cannot be tightly placed: https://www.bikeforums.net/*****************NFPA
When I hold the front brake and move the bike forward/backward, there is no wiggle/vibration, so is this normal or should I be worried if I ride it like this, the frame would be damaged? Also, any solution for this?

Thank you,

P.s:
I live in a country with no bike shops. Does anyone know a Cannondale dealer who could help me getting the 5mm Top Cap?

That's not a top cap. That's a conical spacer. Its OK if it spins round. As long as there is no back and forth play between the fork steerer and headset everything is OK.

The top cap is above the stem. If you lossen the stem bolts then tighten the top cap bolt. Then re-tighten the stem bolts. The gap will be eliminated. Its still normal for the conical spacer to spin abit.

The stem is loosened around the steerer tube, the steerer tube must be 4~5 mm shorter than the top of the stem , if not so,

You have to add a A Spacer , that can be added on top of the stem or beneath the stem .

The spacer ring, is that 5mm you seek, not a different top Cap

Just has to not bottom out the underside of the cap against the end of the Fork's steering tube.

the bolt in the Top cap is what does the headset bearing Pre Load adjustment, stem is just another spacer in that situation, once loose,

once that adjustment is done to satisfaction, Tightening the bolts behind the Stem locks that adjustment in place.

Thank you for clarifying that for me! I thought it was called "top cap" as it is written in Cannondale specification.

I did loosen the stem bolts and tighten the top cap with the required torque multiple times. However, that did not seem to solve the problem.
But if this is normal as you said then I think it is ok. It's just a new frame and I am a bit worried. Thank you!

your conical spacer need not spin, do the headset adjustment with the bike wheels on the ground.

Remove and look under the top cap and see how much higher the top edge of the stem is than the end of the steerer tube it grips.

Absolutely correct, even Campagnolo referred to the hidenset headset design with the longer conical spacer as TTC or tall top cap, so your confusion is totally understandable. As others have stated, what is commonly referred to as a top cap for a threadless stem system is the piece that is placed on top of the stem used to adjust the bearing preload of the headset. The top cap pulls the fork up and pushes the stem and spacers down to set the preload and the the bolts on the side of the stem lock the adjustment in place. There needs to be a slight gap (+/- 5mm is recommended) between the top of the steerer tube and the top of the stem to allow the top cap to do its job...if it contacts the top of the steerer tube it may not allow enough compression to properly adjust the headset.

-j

Thank you! I hope that I didn't cut the fork too short. I'll try this and what others mentioned. Hope it works!

If you cut the fork too short for the tall top dust cap (conical spacer) there is another version of the hiddenset that has a much shorter, relatively flat top dust cap. If needed you may be able to pick one up off ebay if you LBS does not have one.

-j

I tried to look for that 5mm hidden spacer everywhere but with no luck. Any idea where I might find one?

I am not sure what you are looking for....there is not a hidden spacer in your headset. Your headset is a hiddenset integrated headset design, which means the bearing cups are integrated into the headtube of the frame.

If you need to replace your TTC (tall top cap -refering to the dustcap spacer) with a normal size one you may need to purchase new headset. Not know the exact specs of what you have, I can only guess at what would be a good replacement. I don't recall very many headsets on the market that look like what you have and most are campagnolo hiddenset clones/compatible...so this is my best guess for an affordable replacement with the normal/lower top dust cap:

New on Sale FSA Orbit CE Headset 1 1 8" Fits Campy Hiddenset Campagnolo | eBay

First thing you should do is ensure your fork is cut to the appropriate length. With the headset and stem installed there should be a 5mm gap from the top of the steerer tube to the top of the stem...much more of a gap than and your fork is considered too short; a gap less than 5mm may allow the top cap used to set the preload to bottom out against the top of the fork steerer tube when the bearing preload is set.

good luck

-j