New stem cap

[Thomson]

I have a 2019 cannondale synapse. I would like to buy a new bits and pieces for it. One thing is a new top cap. The thomson one as that’s my surname. They come in black and silver and I will only buy the black one. I am stuck on what size I need and as I don’t know how to measure my current top hat size. Any help? On Evans cycles it says my headset bearing is 1 1/4 inch and standard top cap is 25mm. The thomson caps come in 1 1/2 and 1 1/8 inch. Any help would be great?

Thanks.

 

[Thomson]

Anybody?

 

[Drago]

Measure the existing cap?

 

[mcshroom]

Most stem caps are 1 1/8" I don't have a synapse but the fork steerer and spacers look normal so I'd guess it is the same.

The fork is fully carbon, so check whether your current stem expander has a single bolt through it, or whether the cap screws on to the bung independently, like my merida does. Usually that means you have a 6mm hex hole in the top of the cap, instead of a steel bolt.