Tubeless road tyres have been on the market since 2006 – but you could be excused for not noticing. But after three years’ development, Schwalbe think their new Ultremo ZX Tubeless tyre offers a breakthrough in performance and design that will help it become mainstream.
A high performance road tubeless tyre needs to be easy to fit without any specialist tools, operate safely at around nine bar – 130psi – whatever the conditions, to not leak air, but to still have a similar sized bead to conventional clinchers because of wheel constraints. Most of all, it must still be competitively light.
An Ultremo ZX clincher and light inner tube weigh around 295g, whereas our tubeless versions weighed 308g each, which is impressive considering the completely new construction.
For strength and resistance to stretch, the bead contains carbon fibre, and the whole carcass is reinforced for integrity and puncture protection. The carcass has a butyl liner, vulcanised to make a single layer, saving unwanted friction and hugely reducing rolling resistance – Schwalbe claim it’s lower even than their lightest Ultremo ZLX clincher.
The reinforced carcass offers extra snakebite protection, and sudden deflations are almost impossible. With no tube to burst, a puncture usually results in only slow loss of air.
Schwalbe recommend adding 30ml of Doc Blue (made by Stan’s) sealant per tyre, which has no effect on rolling resistance but can seal multiple holes, even in the sidewall, in a split second with only nominal pressure loss.
We used Schwalbe’s Easy Fit Fluid applicator on the tyre beads, and fitting to our tubeless wheels was no harder than some clinchers. It evaporates after use, and after a few minutes of persuasion we inflated our tyres with a standard track pump – usually with tubeless tyres you need a compressor pump.
At various pressures the tyres feel smooth and surprisingly supple, the sidewall seemingly more flexible than with our clincher version – with the bonus of being able to run at lower pressures without risk of a pinch flat.
They feel more pliable than other tubeless tyres we’ve tried, and compared with the standard Ultremo ZX – one of our favourite race treads – they’re as rapid, corner with the same confidence, and react instantly when sprinting. Daily air loss was no greater than from a clincher tyre – and less than from a tubular – and they’re utterly reliable.