Road tubeless is a technology that has a lot of folks excited, yet the roll out has been a bit slower than expected. With Hutchinson more or less leading the way, for a while any other tires were simply rebranded Hutchinsons, however other companies seem to be closing the gap and bringing their own tires to market. Schwalbe happens to be one of those companies as they offer their new Ultremo ZX Tubeless road tire which was first introduced at Interbike, and is now about to enter the wild. Billed as the lowest rolling resistance tire that Schwalbe makes across the board, the 700x23c tire is apparently the fastest tire they make.

We threw it on our scale to test out the claimed weight, after the break.

Keep in mind that this is a pre-production sample, so 309 isn’t terribly far off from the claimed 290g.


  1. Matt on

    Give me something wider.

    Would love to have 28-32 for commuting. Just today I got a tiny piece of glass that should have just been a pull & seal deal with tubeless, but instead meant a whole tube change and a no-go time-wise to tack on a fun portion to my ride.

  2. Jacob on

    I agree, needs bigger graphics. Not sure if people will know that you are riding tubeless… (just kidding, I’m sure the final production model will look different).

  3. MattS on

    Echoing calls for wider options, please. 25 and 28 in the same casing construction to start. Once 25s are available, I will never buy a 23 again for the road.

  4. isaac on

    Specialized and Trek both already have 25s available, pair that with the new 25mil width Belgiums and you may have an almost bearable tubeless road setup. 309 grams for a tire is bullcrap, you can run a nice tire and put Stans sealant in your tube and come out with lower weight.

    • Zach Overholt on

      @isaac, first I have to give you props for mentioning Tactical Nuclear Penguin in your blog post, second check back tomorrow for a tubeless road tire that might be more your style.

  5. Dustin on

    Running wider and wider tubeless tires (at high pressures seen on road bikes) can create several engineering challenges because the wheel must take more and more of the pressure. This is less so the case with tube/clinchers and non-existent when considering tubulars.

    Want a supple ride with no flats? I’d try out a wide tubular with stans in it. Probably just as easy to set up and change as some of these tubeless set ups anyway…

  6. Velo on

    > I wish people would stop saying “23c” or “28c.” Tire width is measured in Millimeters.
    > The size is 700C by 23mm.

    Well the diameter is in millimeters too… so you just violated your own rule by saying 700C instead of 700mm.

    Almost every bicycle tire manufacturer designates their tires in the manner 700x23C.

  7. Johnny on

    All: the “C” in 700C stands for “clincher.” They are 700mm wheels (measured with a tire installed, so you’ll never really get an exact 700mm diameter, but that’s the theory), and called 700C for clincher wheels.

    Hashbrowns is right – tires are measured in millimeters. They are also labeled 23c or 25c, though, because they are clincher tires.

  8. bob on

    > Well the diameter is in millimeters too… so you just violated your own rule by saying 700C instead of
    > 700mm.

    I hope you know how stupid you sound. Go read yr Sheldon Brown.

    (700c tires are 622mm bead to bead circumference)

  9. Velo on

    @mateo: I made no claim that C stood for cm. Perhaps a visit to your optometrist is in order.

    @Johnny: The C doesn’t stand for clincher. Nor does it stand for cm.

    @bob: Everything I said is correct, and you are the one that needs to re-read Sheldon Brown.

    Let’s restate the facts. We are referring to tires which measure approximately 700mm x 23mm. The common nomenclature for these are 700x23C. You will find that nomenclature in nearly every manufacturer’s product literature.

    Hashbrowns stated “I wish people would stop saying 23c or 28c. Tire width is measured in Millimeters. The size is 700C by 23mm.”

    I pointed out the the internal inconsistency of Hashbrowns’ request, that tire widths must be denoted with the accompanying mm designation under penalty of death, but somehow it’s okay to put the C behind the 700 when in fact the 700 is in mm too.

    And then it went downhill from there.


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