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Shimano Gravel 1x12 becomes wireless
by Patrick Bardelli
Czech tyre manufacturer Zleen takes a radical approach
7.7.2025
Translation: machine translated
Pictures: Patrick Bardelli
Zleen is taking an unusual approach to bicycle tyres with a special carcass. The Czechs recently presented their new MTB tyre at Eurobike.
«Racerunner Radical» is the name of Zleen's new mountain bike tyre, which the brand recently presented to the public at Eurobike in Frankfurt am Main. According to Petr Vysloužil, Marketing Manager at Zleen, the centrepiece of the new tyre is the 88° radial carcass.
After Schwalbe launched the radial tyre «Albert» caused a sensation in 2024, Zleen is now launching a model that goes one step further at 88°, according to Vysloužil.
In radial tyres, the carcass threads usually run at a 45° angle (radial) to the direction of travel, in contrast to the diagonally arranged threads in cross-ply tyres. Here there are significantly more. «This is a decisive break with the traditional cross-ply construction», says Petr Vysloužil and lists the advantages of this construction:
- 30 per cent larger contact area for more grip and precise cornering
- 70 per cent higher tyre pressure for 40 per cent less rolling resistance and more efficiency per pedal revolution
- 25 per cent weight reduction to 550 grams without compromising on strength and protection
Source: Zleen
Unique cross-section also for gravel bikes?
«Our new tyre is characterised by a slim profile and a wide tread zone and, thanks to its uniquely shaped cross-section, offers great resistance to cuts and snakebites», Petr Vysloužil continues.
The new tyre is set to be launched on the market in the coming weeks. In the meantime, gravel bike manufacturers are also launching their bikes with a tyre width of 50 millimetres or more (54 mm tyre clearance, as with the new Grizl models from Canyon). So the next step is obvious: after the MTB, the 88° radial carcass should then also be used on gravel bikes.
Our purchasing department will clarify whether and when we will have the «Racerunner Radical» from Zleen in our range. If possible, we will then test the technology and report on it.
Header image: Patrick Bardelli
Patrick Bardelli
Senior Editor
Patrick.Bardelli@digitecgalaxus.chFrom radio journalist to product tester and storyteller, jogger to gravel bike novice and fitness enthusiast with barbells and dumbbells. I'm excited to see where the journey'll take me next.
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