Let me start by saying this lock feels like it was forged in a superhero's workshop. The moment I unboxed the OnGuard RockSolid, the 14mm shackle with its beefy rubber coating screamed 'try me, thieves!' That diamond-coated exterior isn't just for show - it genuinely dulls angle grinder blades, which is crucial in today's world where battery-powered grinders are the new burglary tool of choice.

In real-world use, I've locked my premium e-bike outside coffee shops for hours without that nagging worry. The X4P locking mechanism clicks satisfyingly at four points - you can practically hear the security. Though fair warning: there's slight shackle rattle (about 1mm play) that perfectionists might notice during transport.

The size is Goldilocks-perfect for most frames - my Tern QuickHaul fits snugly between chainstay and rear wheel. But measure carefully if you've got fat tires or need to secure to fixed objects; the actual internal space (83x174mm) is slightly less than advertised. Those with 20" wheels might struggle threading through spokes.

At just 3lbs, it's shockingly lightweight for this security tier - nearly 1.5lbs lighter than my old Kryptonite New York lock! I toss it in my pannier or clip it to the rack without feeling like I'm hauling an anchor. Bonus: FIVE keys included (though none glow-in-the-dark - a missed opportunity for night riders).

The trade-offs? No included bike mount (unlike some competitors), and that anti-grinder coating adds bulk - the shackle becomes a chunky 25mm square when sheathed in rubber. But considering it combines Sold Secure Diamond rating with actual angle grinder resistance at this price? Absolute game-changer for urban cyclists.