Originally Posted by
jtgotsjets
There are people here who have come up with all kinds of reasons to dislike quill stems, but it's mostly hyperbole. If threadless stems are stiffer, it's at an order of magnitude impossible for mere mortals to detect. Maybe they're slightly more versatile, since you can flip them. Is this really such a big deal?
There are advantages and disadvantages to both. Neither is clearly superior. I suspect that the primary reason the bike industry has moved to threadless is because it makes things cheaper to manufacture (even though consumers have never seen a price drop that reflects this).
The way I see it, if threadless was truly superior, there wouldn't be so many bikes still being manufactured with quill stems. Think of any other 20+ year-old design improvement on bikes—if they were any good, they became 99% standard.
The difference in stiffness between a 22.2mm diameter quill stem to a 28.6mm threadless is more evident the longer it gets. The threadless can also be made in carbon fiber or aluminum, which is much lighter than a fork with steel steerer.
There's really no disadvantage to threadless stems over quill stems, other than price, which is evident in that no one would recommend switching from a threadless fork to threaded fork for the sake of using quill stems. You don't see a cost saving in threadless, because manufacturers can use more complex materials or draw tubes thinner to take advantage of the better interface and that costs more money.
the one place you find a lot of quill stem usage are on are cheap department store bikes made from hi-ten steel. keeping the quill stem on these sorts of bikes also makes it cheaper to hobble together useful bikes from older junk bikes.