Modern stems

[Alan O]

This might be a stupid question, but after my return to cycling last year as something of an old git, I really do wonder what are the benefits of modern stems over old-fashioned quill stems.

The big advantage of quill stems to me seems to be that they're easily adjustable. I've been able to fiddle with mine with millimetre changes, even while out on a ride, until I've got them perfect for my (slightly stiffer) older body.

So what advantages of modern not-easily-adjustable stems outweigh the flexibility of quill stems?

(Genuine question - I really don't know and I've been meaning to ask for ages.)

Alan

 

[Hugh Manatee]

The front unscrews. I prefer quills.

 

[raleighnut]

Cheaper to make?

 

[Ian H]

The major advantage seems to be much easier and more reliable headset adjustment. In engineering terms, I think it probably counts as a bit of a bodge, but then so was the old quill system.

 

[GrumpyGregry]

old school threaded headsets needs special tools to adjust, and seemed to go out of adjustment fairly easily and often. Aheadstems don't. Old school headsets tend to be heavier but first and foremost aheadsets are cheaper to make meaning more profit for the brand.

 

[screenman]

The new system makes you keep up a stretching regime, which we know is good for young and old.

 

[Globalti]

I disagree. After decades of bodging bikes and hating threaded steerers for their difficulty of adjustment I find modern stems a simple and robust solution. Nothing is easier than undoing the three bolts and dropping out the forks then replacing and tightening down the stack.

 

[dan_bo]

Stiffer
lighter
easier to assemble

 

[derrick]

Look cooler.

 

[Dan B]

While I much prefer the look of a quill stem, it's nice to have something to hold onto while climbing that doesn't creak and flex

 

[Alan O]

Nothing is easier than undoing the three bolts and dropping out the forks then replacing and tightening down the stack.

Not even loosening a little with an Allen key and adjusting it on the go, with no removal of forks, and no need to even know what a "stack" is?

 

[Alan O]

While I much prefer the look of a quill stem, it's nice to have something to hold onto while climbing that doesn't creak and flex

Bit of creaking and flexing, yep, that's happened to me.

 

[ChrisEyles]

For off-road riding, I prefer the modern threadless set-up, which seems to be less prone to working loose over rough ground, and a bit easier to set up "just so". Quill stems do look far nicer IMO though!

 

[si_c]

Nothing beats a Cinelli A1 for looks. Just saying.

 

[Yellow Saddle]

The threadless stem AKA Aheadset, is an engineering marvel and a huge improvement over the old system. With a quill stem, the attachment point between the stem and steerer is at the bottom of the stem via an expansion wedge. This leaves the top part of the stem inside the steerer tube unsupported and the source of many groans and creaks. The worst feature of this stem is its water pumping action. When riding, the stem moves inside the steerer and massages water and grease together to form an emulsion. This corrodes the aluminium stem and makes it swell and stick forever inside the steerer. This was a big problem with quills - you lost about 25% of them by having to saw them off and machine them out. In addition, quills have to be made from reasonably solid alumium in order to get flex strength in that thin diameter.
The threaded headset itself is a problem in that you require special tools to adjust it. I know some like Stronglight could be adjusted without special tools but those were an anomaly.
The threadless system solves a few problems. The steerer can be made from any material, including carbon. Aluminium and carbon are widely used as steerers nowadays but it would never have been possible with threaded headsets since you can't thread these two materials in that situation. However, that wasn't envisaged with the original patent some 30 years ago, it is a nice bonus now.
The threadless stem clamps the steerer rather than expands inside it. The double bolt gives rigidity that a quill could never give and of course, eliminates noise because there is no relative movement between stem and steerer. The one-tool adjustment is a pleasure to use.
The only downside is vertical adjustment. Looks are in the eye of the beholder.