Schwalbe Marathon 28 x 2.15" Wired Reflex City Bike Tyre - DualGuard / TwinSkinSchwalbe Marathon 28 x 2. 15" Wired Reflex City Bike Tyre DualGuard TwinSkin 1 tire. 4 seasons, 365 days no tire change necessary. The Marathon GT 365 is the first tire which you will ride safely throughout the year in almost every condition. The new lamella tread and the specially developed FourSeason compound provide full grip, no matter what time of the year. Of course fitted with DualGuard puncture protection technology for maximum safety. Season: