Bicycle Mechanics - steer-tube - stem-riser - adapter questions

Parts are as follows:

1" steer-tube threadless fork & headset
1&1/8" stem
Stem riser (to be determined)
1" to 1&1/8" adapter sleeve

Assuming I need the additional rise of a stem riser, what is my best option - to install a 1 to 1&1/8" adapter and then put on a 1&1/8" stem riser or to install a 1" stem riser and then install the 1 to 1&1/8 adapter?

No matter how I do this, the "ears" of the actual stem will be clamped not to the steer-tube itself, but rather to a potential slip-ring around the steer-tube. What keeps the 1" to 1&1/8" adapter from rotating freely about the steer-tube, causing loss of steering?

Thanks!

Parts are as follows:

1" steer-tube threadless fork & headset
1&1/8" stem
Stem riser (to be determined)
1" to 1&1/8" adapter sleeve

Assuming I need the additional rise of a stem riser, what is my best option - to install a 1 to 1&1/8" adapter and then put on a 1&1/8" stem riser or to install a 1" stem riser and then install the 1 to 1&1/8 adapter?

No matter how I do this, the "ears" of the actual stem will be clamped not to the steer-tube itself, but rather to a potential slip-ring around the steer-tube. What keeps the 1" to 1&1/8" adapter from rotating freely about the steer-tube, causing loss of steering?

Thanks!
Clamp the riser directly to the steerer tube and put the 1-1/8" - 1" reducer bushing inside the stem.

The reducer is split lengthwise and has a slight gap so as the stem clamp bolts are tightened it squeezes down slightly and makes a tight, non-slip connection. The stem's clamp bolts, if tightened properly, won't let the stem slip even with the reducer bushing in place. Not to worry.

Clamp the riser directly to the steerer tube and put the 1-1/8" - 1" reducer bushing inside the stem...

Hi HillRider!

You're right about the reducer being split - I hadn't noticed that because I hadn't taken it out of the packing! Your suggestion to clamp the riser directly to the steerer tube, though, won't work.

The riser (if it's to fit the stem) must be 1 & 1/8 inch. The fork steerer tube is only one inch. The only way to make this work (as I understand it) is to put the bushing on first, then clamp the riser onto the bushing, then install the stem. The only "connection" between the bars and the steerer tube will be the stem's clamp on the riser and the riser's clamp on the split bushing. The parts will be held in place (axially) by star-nut tension. Is this adequate for radial steering forces?

Thanks!

What keeps the 1" to 1&1/8" adapter from rotating freely about the steer-tube, causing loss of steering?

As long as the pinch bolts are torqued properly, there's absolutely nothing to worry about.

As long as the pinch bolts are torqued properly, there's absolutely nothing to worry about.

Thanks, Fixer! I'll do it right.

As long as the pinch bolts are torqued properly, there's absolutely nothing to worry about.

Thanks, Fixer! I'll do it right.

Fixer is correct, but in my defense, your OP mentioned a 1" riser meaning the riser clamped directly to a 1" steerer but took a 1-1/8" stem with a reducer.

If the riser is 1-1/8" at both ends, sure, you have to put the reducer over the steerer and ,as Fixer said, clamp the bolts properly and you have no problems.