The Schwalbe Ultremo ZX tyre provides a supple, comfortable ride and seals easily in the event of a puncture. Crucially, it is not notably slower than its clincher equivalent, even when rolling at lower pressures.
After many years of trail riding on tubeless tyres, I was intrigued to see how a road version would perform. Enter the Schwalbe Ultremo ZX, the tubeless incarnation of our favourite summer road tyre, and so ideally placed to offer a direct comparison with a clincher.
We made a detailed inspection of the ZX tubeless in our ‘first look’ article, where you can find all the tech specs, including weight and construction. If you’re keen to know more about how tubeless tyres work, and the logistics of installing them, click here.
In this article, we’ll focus solely on the performance of the Ultremo ZX tubeless, one for which Schwalbe make some bold claims, specifically around speed, a quality the German brand claims is generated at least in part from the absence of friction between tyre and tube.
Armed only with a series of well-known test loops, we set about testing Schwalbe’s laboratory data in the real world. How? Tubeless has become de rigueur in the mountain bike world by allowing our trail-bound brethren to run lower pressures and enjoy two distinct advantages: greater grip from an increased contact patch, and reduced puncture rates (see how much easier it is to burst a fully inflated balloon than a ‘soft’ one).
Would the same hold true on the road, and what would be the consequence for speed? Harder is faster, right? We ran the tubeless Ultremo ZX some 20psi lower than its clincher equivalent (100psi rather than 120psi) and experienced no notable drop off in speed. Rather than bouncing around on the rough surfaces of our rural test routes, the lower pressure of the tubeless kept us in contact with the ground for longer. As an added bonus, we experienced greater comfort, too.
Schwalbe’s next claims concern increased grip and with it, better cornering. While we hadn’t experienced issues in either department with the ZX clincher, the tubeless was certainly confidence inspiring, notably absent of sidewall movement or related handling issues. The absence of a tube to support the sidewall raised the spectre of air loss, and the potential for the tyre to become unseated. Happily, these fears proved to be entirely unfounded, a tribute to the quality of the tyre construction, notably its carbon bead (and not to mention the rim – Easton’s EA90RT, since you ask). The upshot? A compliant, supple ride with grip in abundance.
Puncture resistance provided the subject of another bold claim from Schwalbe. Did the claim, and indeed the tyre, hold up? I seem to be on a roll with avoiding punctures recently (cue the end of that) but was impressed by the outcome when a small stone penetrated the cover of the ZX tubeless. I rotated the wheel so the hole was at the ‘bottom’, forcing the sealant to flow to the breach and, well, seal it. I’d estimate a loss of about 30psi from this episode, which I topped up (it’s wise to carry a pump, even when using tubeless) and then rode 20 miles home without further inconvenience. Still more impressive was that the tyre required no further attention before the next ride, short of the routine, pre-ride pressure check.
Schwalbe also claim that tubeless tyres do not not suffer the kind of instant blowouts caused when an inner tube is breached; rather the loss of air occurs in a slower, and more controlled manner. We didn’t experience any sudden pressure drop in our test period (the incident described above was the only occasion on which we punctured) but our experience off-road with tubeless tyres lends credence to the claim.
The Ultremo ZX is Schwalbe’s first attempt at a tubeless road tyre and after an eight week test, we’d say they’d hit the ground running. Having enjoyed the benefits of tubeless tyres for many years off road, I would not now build a new bike of my own without running this system or one similar.