I'm considering replacing my threaded aluminum forks, threaded headset, steel threaded stem and steel handlebars with threadless carbon forks, threadless headset and integrated carbon stem and handlebars; a large reduction in weight on my 700c road bike.

Aside from weight, what performance differences (if anything) should I notice or expect from the 1.0" threaded (guess) / 1 1/8" threadless headset change? Smoother turning? Or had the change in the industry been motivated on weight/production considerations?

One thing that I miss from the threaded setups is that the stem and forks can be engaged in a much stronger connection, such that it would take way more force to make them move independently. On my threadless setups, I can still force the handlebars to turn independent of the wheel, as the stem bolts strip out before they would provide as much clamping force as a threaded setup.

  • 4
    Are you sure your 1" headtube will accept a 1 1/8" headset and fork?
    – mikes
    Commented Mar 22, 2015 at 18:43
  • 2
    How much force are you applying to get the stem to move independently of the fork? I can't imagine that you would encounter such a force except under crash conditions. Maybe you need a new stem bolt that won't strip out so easily.
    – Kibbee
    Commented Mar 22, 2015 at 19:55
  • 4
    I have a feeling you've got your threadless system setup wrong if you're able to force the stem to spin around.
    – Batman
    Commented Mar 23, 2015 at 0:18
  • 1
    I've had various bikes with threadless headsets for 18+ years and I've never had an issue with movement between fork and stem. I assume you've already tried the gritty carbon assembly goo ? I suspect your stem/handlebar combo may be to blame. Your experience is certainly not typical of threadless headsets and stems.
    – Nik
    Commented Mar 23, 2015 at 4:55
  • 3
    Carbon fiber started crackling some? With CF you're always supposed to use the torque wrench. Maybe you damaged the CF by overtightening.
    – Batman
    Commented Mar 23, 2015 at 19:57

2 Answers 2


Theoretically, you can adjust the height of a threadless headset moving around the position of the spacers. The problem is that most threadless headsets come with very little room (or none at all) to adjust the stem up and down. The leaves the only way to adjust the height is by purchasing a new stem, which doesn't give you the option of switching mid ride.

Also worth pointing out that while the connection on a threaded headset may be stronger, the threadless setup is strong enough for most riding conditions. Threadless headsets are used on all kinds of bikes, from road, to mountain, and even downhill. If it didn't provide a strong enough connection, you wouldn't have manufacturers risking lawsuits with something that is known to be inferior.

Also, a threaded headset has a single point of failure that's difficult to inspect. If you are using the style of quill with an expander (see below) there is a decent chance that over time the stem will break from the pressure of the expansion (I know someone it happened to, twice). With a wedge style, this not a possibility, but you still have a single point of failure if wedge nut or bolt brakes, or even if it loosens over time. There's always 2 bolts on threadless, so no single point of failure, and it's easier to inspect what's going on to see early signs of wear.

The biggest problem I know of with threaded headsets though is that the stem has a tendency to rust to the steerer, and is sometimes practically impossible to remove. This is preventable with regular maintenance, but there's a lot of bikes out there that don't get as much maintenance as they need, and most non-enthusiasts would probably never think of checking the quill for rust and regreasing a couple times a year. Most people would probably be afraid to disassemble the headset to ensure things aren't starting to rust, and many people don't like going to the bike shop for things until something actually isn't working because of high prices.

Quill Stem Styles


Threadless forks aren't a significant upgrade in any way other than weight and simplicity of setup/maintenance.

Depending on exactly what the steerer tube is made of and how much is exposed above the headset, they can be stiffer when pulling on the bars in a sprint, but for the other 99.9% of the time there is no difference.

Having said that, I'd would never go back. The advantages in weight and maintenance are well worth it.

P.S. You should really double check your measurements, a 1.125 inch threaded headset is a relatively rare item. They were made, but only for a few years and as far as I know only on mountain bikes and tandems. It would be very rare to find one on a road bike of any vintage.

  • I didn't measure here. The head tube is the right diameter to accept a 1.25" threadless headset. It currently has a threaded setup. Does that make it a 1.0" threaded headset then?
    – Ehryk
    Commented Mar 23, 2015 at 19:40
  • 1
    The 1.125 is the dimension of the steerer tube. So the head tube would need to have an interior dimension greater than that. See en.wikipedia.org/wiki/Headset_(bicycle_part) for exact dimensions of the headtube. Commented Mar 23, 2015 at 20:30
  • I'll measure it when I get home; suffice it to say I know it will accept a 1.25" threadless headset/fork if I pressed one in.
    – Ehryk
    Commented Mar 23, 2015 at 20:48
  • Head tube O.D. is 37.4mm, I can't find a good place to measure the steerer tube without removing the stem. It's the 'right size' to press in a standard 1 1/8" threadless headset.
    – Ehryk
    Commented Mar 24, 2015 at 6:11
  • So - why did the industry make the switch? Is it production / costs? Or the larger diameter steerer tube the same head tube accommodate? So far, threaded setups have the advantage of height adjustment without cutting, and a stronger connection, disadvantage of weight. Anything else?
    – Ehryk
    Commented Mar 24, 2015 at 6:14

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