A tangent from my previous post.
↑I've installed a toothed spacer on the fork steerer tube,
and there's a reason for that.
With Time framesets, the headset bearing preload adjustment is completed
at the tall cap portion,
so there's no pressure applied to the spacers sitting above it.
This meant that even when I pressed the stem down firmly and fixed it,
the Di2 connector kept moving side to side.
Since the customer was fine with the current higher position,
I used an accessory from an Easton EC90 stem (probably can't source it individually, and it's discontinued)
to apply pressure.
When I turn the bolt on the toothed spacer after fixing the stem,
the teeth spread open and pressure is applied.
You could say the screw adjustment changes the spacer thickness retroactively.
Even though it's called an EC90 carbon stem, there were periods when
different versions existed under the same name,
and there was a time when you got one that was particularly hard to adjust—like the diagram above.
First, the stem position is limited to the very top of the steerer spacers.
When you tighten the cap (nut) on top of the stem, it fixes the fork steerer,
but it simultaneously fixes the steering left and right as well,
so you have to set everything at once to make sure the stem points straight ahead.
That's why there's no side-adjustment bolt on the steerer side.
When removing the stem, you have to release the bite of the angled spacer,
so you loosen the cap and then put your weight on the handlebar to "drop" the stem.
Since you need clearance for this drop, you can't put
a toothed spacer directly under the stem.
The red spacer in the diagram above (5mm thick) has a structure where
two pieces—each covering 180°—are joined together,
and once assembled, you slip a rubber band into the groove.
This thickness becomes the "drop clearance."
The spreading amount of the toothed spacer (the force it applies) isn't huge.
When you fully tighten the stem cap (fixing the stem), the stem height drops ever so slightly.
So when setting up, you need to include standard spacers as well, and adjust
so that when the stem is fully tightened, the steerer gap becomes
just barely enough for the split spacer to fit (just over 5mm),
then install the split spacer and spread the toothed spacer
to remove any play.
It's not a simple job.
As far as I know, this is the most tedious stem to adjust.
I happened to have one of these toothed spacers personally,
and it came in handy, so I used it this time.
There's a similar product called USE Ringstar, which has a larger play-removal range
but is also thicker, so I went with the old EC90 accessory instead.
↑I've installed a toothed spacer on the fork steerer tube,
and there's a reason for that.
With Time framesets, the headset bearing preload adjustment is completed
at the tall cap portion,
so there's no pressure applied to the spacers sitting above it.
This meant that even when I pressed the stem down firmly and fixed it,
the Di2 connector kept moving side to side.
Since the customer was fine with the current higher position,
I used an accessory from an Easton EC90 stem (probably can't source it individually, and it's discontinued)
to apply pressure.
When I turn the bolt on the toothed spacer after fixing the stem,
the teeth spread open and pressure is applied.
You could say the screw adjustment changes the spacer thickness retroactively.
Even though it's called an EC90 carbon stem, there were periods when
different versions existed under the same name,
and there was a time when you got one that was particularly hard to adjust—like the diagram above.
First, the stem position is limited to the very top of the steerer spacers.
When you tighten the cap (nut) on top of the stem, it fixes the fork steerer,
but it simultaneously fixes the steering left and right as well,
so you have to set everything at once to make sure the stem points straight ahead.
That's why there's no side-adjustment bolt on the steerer side.
When removing the stem, you have to release the bite of the angled spacer,
so you loosen the cap and then put your weight on the handlebar to "drop" the stem.
Since you need clearance for this drop, you can't put
a toothed spacer directly under the stem.
The red spacer in the diagram above (5mm thick) has a structure where
two pieces—each covering 180°—are joined together,
and once assembled, you slip a rubber band into the groove.
This thickness becomes the "drop clearance."
The spreading amount of the toothed spacer (the force it applies) isn't huge.
When you fully tighten the stem cap (fixing the stem), the stem height drops ever so slightly.
So when setting up, you need to include standard spacers as well, and adjust
so that when the stem is fully tightened, the steerer gap becomes
just barely enough for the split spacer to fit (just over 5mm),
then install the split spacer and spread the toothed spacer
to remove any play.
It's not a simple job.
As far as I know, this is the most tedious stem to adjust.
I happened to have one of these toothed spacers personally,
and it came in handy, so I used it this time.
There's a similar product called USE Ringstar, which has a larger play-removal range
but is also thicker, so I went with the old EC90 accessory instead.