Having a blonde moment here. After trawling around i bought the Superstar angular contact bearing 40x52x7 45×45 degree to replace the crappy Arcos one that fell apart.

The problem is the bearing seems to sit on a lip and does not go into the frame as seen in pic 1

When the bearing is inserted as far in as it will go it ends up looking like this

Am i missing something here?

Rather than ‘missing something’ I’d say you possibly have too much?

You say the old bearing fell apart – is that part of it still in the frame?

Edit to add – actually it doesn’t look like the old bearing race… Do you still have the old bearing to compare the new one to?

Canyon say the bottom bearing sits into the frame without a Cup, It’s semi-Integrated. The old one is the Ball bearing version.

The lower headset is integrated 52mm headtube internal diameter and 40mm steerer diameter so there isn’t a cup and the bearing sits directly in the headtube however mine wont as it sits on the Lip in pic 1

Old Left New Right

When i google ACROS AI-03 The baring is the same as the one on the right and not the ball bearing that i have removed?

O dear…. 😉

the old outer race is still sat in the frame you will need to get it out either with a puller or a hammer and a drift or something

Cheers Sancho.