The best stem for carbon steerer tubes

[matteof93]

I am looking for an aluminium stem that allows to correctly spread the clamping force of the stem over a large area of the steerer tube.
Basically, I am looking precisely for the opposite of popular stems like the Extralite ones.

This is an example of what I do not want to use


This is an example of what I would like to find


Any idea?

[tjvirden]

Most are much nearer the top in terms of cut-out, as you have discovered.
Bontrager Race X Lite has a smaller cut-out than many, and works well on carbon steerers and bars in my experience. I've also had success with Ritchey C220/C260 and 3T Arx (first generation), but the cut-outs are larger than the Bontrager.

[alcatraz]

The op is using his head on this one. So many people just trust the brand and ignore common sense. Of course the stem at the top (at a certain clamping force F) is going to leave a deeper nastier imprint on the steerer tube.

[matteof93]

The op is using his head on this one. So many people just trust the brand and ignore common sense. Of course the stem at the top (at a certain clamping force F) is going to leave a deeper nastier imprint on the steerer tube.

There is also another option: using a 1" 1/4 (or 1" 1/2) stem with an adapter for the standard 1" 1/8 steerer tube. I think that the adapter is thick enough to evenly spread the clamping force.

[Cemicar]

~I believe every Bontrager stem has no cutout in the clamping zone~ (no, actually XXX carbon or a few only).

Btw, what's the point of this small pin-hole? I don't think it reduces much weight nor the stem really needs hole to a drain water... The diameter doesn't seems enough big for a electronic cable.

[wannabefast]

I believe every Bontrager stem has no cutout in the clamping zone.

Btw, what's the point of this small pin-hole? I don't think it reduces much weight nor the stem really needs hole to a drain water... The diameter doesn't seems enough big for a electronic cable.

I think it's for heat escape/relief during the production/forging process, otherwise the metal might warp or something.

[mikemelbrooks]

I believe every Bontrager stem has no cutout in the clamping zone.

Btw, what's the point of this small pin-hole? I don't think it reduces much weight nor the stem really needs hole to a drain water... The diameter doesn't seems enough big for a electronic cable.

My guess would be that it's to allow the escape of air during manufacture.

[stevesbike]

The op is using his head on this one. So many people just trust the brand and ignore common sense. Of course the stem at the top (at a certain clamping force F) is going to leave a deeper nastier imprint on the steerer tube.

any imprint on the steerer tube is the sign of over-tightening. There's no need for any torque values about 4-5 Nm for stem/steerer bolts.

[Ypuh]

The op is using his head on this one. So many people just trust the brand and ignore common sense. Of course the stem at the top (at a certain clamping force F) is going to leave a deeper nastier imprint on the steerer tube.

any imprint on the steerer tube is the sign of over-tightening. There's no need for any torque values about 4-5 Nm for stem/steerer bolts.

I torque mine to 4Nm with a Stahlwille torque wrench and it still leaves minor imprints.

[bikewithnoname]

May I ask why you want a stem like this?

Unless you have a paper thin carbon steerer you'll be fine with extralite, I've run them for over 10yrs on various forks without any marks/blemishes.

[MaxPower]

The specialized stems with shims. Enve stem with shims. Zipp has one as well.

They do a fine job with spreading clamp forces. Might be on heavy side though.

Metron 5d (integrated stem/bar from vision) has no holes at all on the clamping area.

[Hexsense]

Bontrager (Blendr Pro) stems are pretty kind to the steerer tube.
But not as kind to carbon bar. It's not bad but can leave a bit of mark on the bar clamp.

[usr]

Would "no hole" actually be better? Better than "reinvesting" the weight saved by the hole in additional clamping surface at the edge?

[DaveS]

The hole shouldn't be a problem unless the stem is over tightened. I use nothing but stems with big holes and never have a problem. My stems for a long time were Ritchey and now I use the zipp sl service course.

[stevesbike]

The Ritchey Superlogic Carbon C260 is probably the most advanced design if you're really concerned. In addition to a huge surface area, the opening has a curved radius design so the clamping force is distributed and has 3 bolts with the middle bolt going the opposing direction and all 3 have a max torque of 4Nm. The faceplate is also well-designed with the stem having a 260 degree wrap on the bar.