Blackburn San Quentin

Bottom line

The Blackburn San Quentin U-lock stands out for its distinctive hexagonal shape, which adds another level of theft protection. However, a flimsy mounting bracket and poor protective coating hurt this lock in user reviews.

Ease of use

Flimsy bracket. The Blackburn San Quentin's long, hexagonal shackle makes it easy to anchor wherever you are, reviewers say. It comes with a mounting bracket, but most users find it difficult to install, and say it feels flimsy and not truly secured to the bike frame. Still, like other U-locks, the San Quentin can be thrown into a bag for transport. At just over 3 pounds, it's certainly not light, but isn't nearly as heavy as most chain locks.

Materials

Thick steel shackle. With an impressive 18 mm alloy steel shackle, the Blackburn San Quentin is an effectively forged bike lock. However, there are some flaws in the materials used. If the mounting bracket plastic is cold during installation, it can be ridged and break easily. The lock features a protective coating on the inside of the shackle, but that doesn't fully protect the bike from nicks and scratches. And more than one owner says the end caps of the lock fall off easily.

Warranty & security

A top performer in security tests. The most unique feature of the Blackburn San Quentin is its hexagonal shape. Reviewers say this prevents bolt cutters -- one of the most commonly used tools by bicycle thieves -- from getting a true grip on the lock. The thick, 18 mm shackle and dual-bolt lock mechanism help it perform at the top of its class in security tests performed at both Men's Journal and Wired magazines.

The San Quentin comes with a $4,000 anti-theft protection plan, which is higher than most U-locks on the market. Still, the top-rated Kryptonite New York Fahgettaboudit Mini (Est. $70) is slightly less expensive and features a $4,500 anti-theft protection plan.