Smallest sprocket doesn't fit on freehub?

Question

I bought a second hand bike with a Campagnolo Super Record 11 groupset (the pre-2015 version). I have been experiencing shifting difficulty since I bought it, and took it to a mechanic. The mechanic advised that I should buy a new cassette and chain.

Today I removed the cassette. As soon as I removed the lockring, the smallest sprocket fell right off of the freehub body. I then removed all of the sprockets, and placed the new ones on.

The issue is that the smallest sprocket doesn't have space to go onto the freehub body properly - it will sort of sit on top and is able to spin. However, I can put on the lockring on and tighten it, and the sprocket seems to be ok after doing so.

However, I'm not sure whether its aligned properly, because it spins before I tighten the lockring.

The bike has Fulcrum Racing 1 rims. The hub is also fulcrum branded but I can't seem to find a model. I'm assuming it came with the rims. Could it be that the hub is made for 10 speed only?

Is this normal and to be expected, or is something wrong with my wheel?

Answer 1

It doesn't really matter if your freehub body is made for 10 speeds, since Campagnolo has the same body for cassettes between 9 and 12 speeds. The body does not go through the smallest sprocket.

The splines on freehub body are not identical and there is one position where the cog fits properly. The lock ring should be not tightened if the cog is not in correct position. The easiest way to find the position is to rotate the loosely sitting cog. Once in correct position, it clicks into place.