I have installed an Across AI 17 to my Titus FTM. When I tighten the stem cap the bearings tighten. I have placed a shim under the plastic collar ridge. This solves the problem but leaves the bearing exposed.

It is possible to file of the ridge but this wont give me any more coverage. A lizard skin will not stay on there. Anyone got any ideas,
Or am I worring about nothing.

If you’re having to introduce addtional shims it sound sliek somethings wrong?

I’d be worried about the shim compressing under load and causing bearing wear. Is it a BB spacer?

also, not quite clear what the issue is of you don’t put the shim in – is it that the bearings won’t preload?

The problem is the plastic collar has a ridge which locates over a nylon split washer. The ridge is longer than the washer so if you tighten the stem top cap the collar applies weight onto the top bearing. This compresses it and tightens it up. With the thin shim in place this adds height to the split washer.