Bicycle headsets and stems have changed a lot in the last couple of decades. For most of the bicycle's history, the standard was the 1-in. fork steerer and threaded headset with a quill stem. There were variations in headset threading; British (which essentially became ISO), Italian, French, JIS (used on some Japanese bikes), and even a few others; and small differences in stem dimensions (22.2 mm for most, 22.0 for French, for example). Although those variations make it a little tricky sometimes when repairing or retrofitting vintage bikes, by the late 80s, things became much easier as British/ISO became the main standard that supplanted most others. Only Italian remained, and it was more or less interchangeable with ISO, so it didn't matter. The 1-in. steerer was (and still is) plenty strong enough for steel-framed bikes.
In the late 80s, the rise of mountain bikes brought the first major change in headsets: the increase in diameter from 1-in. to 1 1/8-in. The way I recall it (though someone is bound to tell me I'm wrong) is that the change was made not so much because the 1-in. steel steerer wasn't strong enough for MTBs -- but rather because the increase in size would improve the life of the headset bearings. The added strength of the fork was a bonus. Yes, I could be remembering it wrong. In time, some MTBs even started appearing with 1 1/4-in. headsets (if big is good, bigger must be better). In the 1990s came the threadless headsets with stems that bolt onto the outside of the steerer, rather than quill stems being inserted and tightened with an expander wedge inside the steerer.
While the threadless headset/stem system first swept the mountain bike market, they took a little longer to take over the road bike market, but they did more or less take over. Today it is hard to find a bike that still takes a threaded headset and quill stem. Although there are certain advantages to the threadless headset system, the advantages are, I believe, more heavily tilted to the manufacturers than the consumers. Easier installation, and less variation in stock - manufacturers no longer needed to keep forks with different lengths of threaded steerers -- it became a one-size-fits-all world (at least for a while -- I'll come back to that).
I don't really have major issues with threadless headsests -- even as a Retrogrouch. They do adjust easily; they give a more "solid" connection between the stem and the steerer; and the stems can even be a little lighter and stronger at the same time. On the other hand, they don't allow for as much adjustability in height. Once the fork steerer is cut to length the options become limited. And on some bikes, especially classic-proportioned steel bikes, they can really throw off the aesthetics. Install a steep-angled stem to get the bars higher, and the look gets pretty weird.
By the way, as far as aesthetics and proportions go, nothing looks "weirder" to me than a carbon fork (usually with hugely oversized blades) on a steel frame. The fork shouldn't be larger than the frame tubes IMO. The stem shouldn't be larger than the frame tubes, either -- but many/most threadless stems are.
Most of the bikes I own have 1-in. headsets and quill stems. All of my bikes are steel; all of them lugged. Quill stems are svelte and have the right proportion for steel bikes. That alone is enough for me.
There really aren't that many "drawbacks" to the traditional quill stem. One argument I hear for threadless over threaded is that you can adjust a threadless headset with allen wrenches which can be carried on a ride, as opposed to the large open-end wrenches needed for threaded headsets. OK - but if the headset is adjusted properly to begin with, there won't be a need to adjust it on the road. Some like to point out that an over-tightened quill stem can bulge the steerer tube. Yes -- so don't over-tighten it. (Interestingly, some of the same people who would make that complaint don't seem deterred by carbon fork steerers that can be crushed by over-tightened threadless stems.) Then there's the issue of stems becoming "frozen" in the steerer because of sweat and corrosion. Yep. That's what grease and maintenance are for. I've only ever seen it happen on seriously neglected bikes.
Back to that one-size-fits-all world. On road bikes, even as threadless headsets took over, the 1-in. fork remained common for a while. As I pointed out, the 1-in. steel fork steerer was more than strong enough. But as forks and steerers started being made in other materials -- first aluminum, then carbon -- the strength of the steerer became more of an issue. In time, 1 1/8-in. became more common on road bikes too -- partly because of the strength issue (at least with non-steel forks), but again, I suspect it makes things easier for the manufacturers -- fewer variations to keep in stock. But now with the all-carbon wunderbikes, there have still been plenty of failures, and the fork-crown/steerer junction seems to be a weak link. It's an issue that gets all-too much ignored. But one should ask themselves why so many carbon-steerer forks are now made 1 1/4-in. at the bottom, tapering to 1 1/8-in. at the top. It's obviously a strength issue, but don't expect to read that in the ads. Anyhow -- I'm starting to digress, so carbon forks are just going to have to be a subject for another post.
| Image may be NSFW. Clik here to view.  |
| I know I used this picture in a different post, but that Nitto I-beam stem is just a gorgeous piece of forged metalwork. |
While the threadless headset/stem system first swept the mountain bike market, they took a little longer to take over the road bike market, but they did more or less take over. Today it is hard to find a bike that still takes a threaded headset and quill stem. Although there are certain advantages to the threadless headset system, the advantages are, I believe, more heavily tilted to the manufacturers than the consumers. Easier installation, and less variation in stock - manufacturers no longer needed to keep forks with different lengths of threaded steerers -- it became a one-size-fits-all world (at least for a while -- I'll come back to that).
| Image may be NSFW. Clik here to view.  |
| Threadless stem - 1 1/8-in. -- Although the Velo-Orange polished aluminum stem is one of my favorites for road bikes, some might find it a bit proportionally large for a steel frame. What is worse though, is the thickness of the spacers -- making the steerer look as big as the head-tube. Since this photo was taken, I had a set of silver spacers thinned down by a machinist. It looks a lot better now. Why doesn't someone just make thinner headset spacers for steel frames? |
I don't really have major issues with threadless headsests -- even as a Retrogrouch. They do adjust easily; they give a more "solid" connection between the stem and the steerer; and the stems can even be a little lighter and stronger at the same time. On the other hand, they don't allow for as much adjustability in height. Once the fork steerer is cut to length the options become limited. And on some bikes, especially classic-proportioned steel bikes, they can really throw off the aesthetics. Install a steep-angled stem to get the bars higher, and the look gets pretty weird.
By the way, as far as aesthetics and proportions go, nothing looks "weirder" to me than a carbon fork (usually with hugely oversized blades) on a steel frame. The fork shouldn't be larger than the frame tubes IMO. The stem shouldn't be larger than the frame tubes, either -- but many/most threadless stems are.
Most of the bikes I own have 1-in. headsets and quill stems. All of my bikes are steel; all of them lugged. Quill stems are svelte and have the right proportion for steel bikes. That alone is enough for me.
| Image may be NSFW. Clik here to view.  |
| Early 70s 3ttt Record stem -- beautiful proportions for a classic steel bike. |
There really aren't that many "drawbacks" to the traditional quill stem. One argument I hear for threadless over threaded is that you can adjust a threadless headset with allen wrenches which can be carried on a ride, as opposed to the large open-end wrenches needed for threaded headsets. OK - but if the headset is adjusted properly to begin with, there won't be a need to adjust it on the road. Some like to point out that an over-tightened quill stem can bulge the steerer tube. Yes -- so don't over-tighten it. (Interestingly, some of the same people who would make that complaint don't seem deterred by carbon fork steerers that can be crushed by over-tightened threadless stems.) Then there's the issue of stems becoming "frozen" in the steerer because of sweat and corrosion. Yep. That's what grease and maintenance are for. I've only ever seen it happen on seriously neglected bikes.
| Image may be NSFW. Clik here to view.  |
| Here's a 1-in. threadless stem -- fillet brazed from chrome-moly tubing. It had to be custom- made, but it does offer a more "classic" proportion for a steel-framed bike. |
Back to that one-size-fits-all world. On road bikes, even as threadless headsets took over, the 1-in. fork remained common for a while. As I pointed out, the 1-in. steel fork steerer was more than strong enough. But as forks and steerers started being made in other materials -- first aluminum, then carbon -- the strength of the steerer became more of an issue. In time, 1 1/8-in. became more common on road bikes too -- partly because of the strength issue (at least with non-steel forks), but again, I suspect it makes things easier for the manufacturers -- fewer variations to keep in stock. But now with the all-carbon wunderbikes, there have still been plenty of failures, and the fork-crown/steerer junction seems to be a weak link. It's an issue that gets all-too much ignored. But one should ask themselves why so many carbon-steerer forks are now made 1 1/4-in. at the bottom, tapering to 1 1/8-in. at the top. It's obviously a strength issue, but don't expect to read that in the ads. Anyhow -- I'm starting to digress, so carbon forks are just going to have to be a subject for another post.