Folding locks split the difference between U-locks and cables in ways that actually matter for daily use. The Kryptolok 610 S from Kryptonite uses six hardened steel links hinged together in an accordion pattern, giving you 100cm of locking circumference that collapses into a compact package roughly the size of a water bottle. That length reaches around a frame, rear wheel, and most bike racks without the geometric puzzle that smaller U-locks sometimes create. The articulating design bends around obstacles that would defeat a rigid shackle, which makes securing to oddly shaped posts and crowded racks considerably less frustrating.

The 5mm link thickness puts this lock in moderate security territory, which Kryptonite rates at 6 out of 10 on their scale. That rating comes with practical benefits: the lock qualifies for Kryptonite's Anti-Theft Protection Offer up to $1,750 and their Key Safe Program for replacement keys. The rating makes sense for errands, coffee stops, and situations where your bike stays within sight. Extended parking in high-theft areas calls for heavier security, but for the daily rhythms of commuting and quick stops, the 610 S covers the ground without weighing down your bag or cluttering your frame.

Kryptonite includes their Click Tight transport bracket, which mounts to bottle cage bosses or straps to frame tubes using the included hardware. The bracket releases with a button press, so grabbing the lock doesn't require fumbling with secondary latches or tools. A rubber coating covers each steel link to prevent frame scratches during transport and use, protecting both the lock and your paint. The 360-degree rotating lock head accepts the key from multiple angles, which helps when you're threading the lock through tight spaces at awkward bike racks. Two keys come in the box, and registration unlocks Kryptonite's replacement key service if you lose one.... Read More