New 650c tire on the market.

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Utremo on the REEN 577
Utremo on the REEN 577


Schwalbe as discontinued the Stelvio in the 650c size and replaced it with the new Ultremo , sweet tire at 170 grams,


Fast tire!
Fast tire!


At the Bacchetta/Catrike Rally I received a set of Ultremo’s to test. I have intentions of using these at Sebring 24 hour race Feb. 14th,, and though it would be a good idea to put a few miles on them before. I mounted then up on a RENN 577 rear disc and Zipp 404 front. Went out and did a workout that have a 45 minute tempo workout that gave me good range of speeds and cornering for the tires, all went well, after fifty miles not indication of any road scars/cuts. Next ride was the Tour de Cape Century ride,, the Ultremo’s did a great job and not a single road cut in them yet after 150 miles.

They handle real well and are a smooth supple ride. I think these high end tires are a winner.

Keep spinning

John Schlitter


Posted in News

6 responses to “New 650c tire on the market.”

  1. Never have I seen a product,bike tires, so confusing. Seems as if every manuf has a different sizing system. Tubes too Soberjohn

  2. Considering that there are still something like 7 models called Stelvio , it’s hard to say that one or another new model is a replacement for “the Stelvio”, though I suppose there was at one time a model called “Stelvio” with nothing following that moniker.

    Anyway, Ultremo, Durano, both pretty cool names.

  3. There is one consistent sizing system for tires and tubes, called ERTRO, which will tell you accurately whether your tire, tube, and rim will all fit together, assuming that you can get ERTRO measurements for all three. Designations like 650C or 26″ don’t help very much.

    Tires and rims have measurements like 23-571 (that’s the 650C Ultremo), with the first two numbers indicating width and the last three indicating the diameter of the tire’s bead seat, which is the interface with the rim. Both the tire and the rim must have exactly the same bead seat diameter, and the tire should have a width between 1.5 and 2.5 times the rim’s width.

    Schwalbe tubes have a sizing system of their own, like the #11 size that fits the 650C tires. They can’t just specify a size because their tubes are stretchier than ordinary and will fit a variety of tire sizes.

    For an overview of the hassles involved in the wacky way that tires are sized, see:

    The Durano is the replacement for the Stelvio, though some sizes of Stelvio are being phased out and replaced with the wider Kojak. The Ultremo is a different tire altogether and is specifically aimed at high-end racing. It has a better puncture protection system than the Durano, but the Durano Plus is probably stronger in both the tread and the sidewall than the Durano, but at considerably higher weight.

  4. Seems like there are three different versions of the Ultremo.
    The base version doesn’t have the nano ceramic goodies.

  5. Schwalbe is very good at pointing out the ERTRO of their tires and even have a very nice search page that will allow you to specify the ERTRO of your desired tire. I find the Schwalbe web site the easiest to negotiate regarding the different tire needs of a recumbent.

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