What Is a Good Bike Lock? 6 Things That Actually Matter
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A good bike lock is one that takes a thief more time, more noise and more specialized tools than your bike is worth to them. No lock is truly unbreakable. Here are the six things that decide how well a lock does its job.
Table of Contents
1. Lock Type
The type of lock matters more than the brand.
- U-locks (D-locks): A rigid hardened steel loop. The best everyday choice for most riders.
- Chains: Heavy hardened links with a padlock. Very secure, very heavy.
- Folding locks: Steel plates joined by rivets. A middle ground that’s easy to carry.
- Cable locks: Braided steel wire. Can be cut quickly with hand cutters, so they’re only good for securing wheels or accessories.
Sheldon Brown’s lock strategy guide, a long-standing cycling reference, recommends U-locks over cables for exactly this reason.
2. Hardened Steel
Look for the words “hardened steel” in the specs. Hardened steel resists bolt cutters and saws much better than ordinary steel. Cheap locks sometimes use softer metal that looks the same but cuts far more easily.
3. Thickness
Thicker shackles and chain links take longer to cut. As a rough guide:
| Shackle or link thickness | Typical security level |
|---|---|
| Under 12mm | Basic, for low-risk areas |
| 12mm to 14mm | Good for daily commuting |
| 15mm and above | High security for cities |
For example, the Master Lock 8320D uses a thin shackle and costs about $12, while the Kryptonite New York Fahgettaboudit Mini uses an 18mm shackle and costs about $180.
4. Independent Security Ratings
Brand ratings like Kryptonite’s own security scale are only useful for comparing models from the same company. Independent testing is a better guide. The UK’s Sold Secure scheme grades bike locks as Bronze, Silver, Gold or Diamond, and you can search a model in the Sold Secure bicycle database. Gold or Diamond is a good target if you lock up in a city.
5. The Right Size
Bigger isn’t always better. A U-lock with a large opening leaves room for a thief to fit a car jack or lever inside and pop it open. A smaller shackle that just fits around your frame and the rack is harder to attack. Make sure it still fits the posts and racks you actually use.
6. Weight You’ll Actually Carry
The best lock is the one you bring every ride. A heavy chain left at home protects nothing. Many riders keep a heavy chain at the place they park most often and carry a lighter U-lock for everything else.
Good Bike Lock Examples
- BUILT TO LAST: The Kryptonite Evolution Mini‑7 U‑Lock is constructed with a 13mm hardened Max‑Performance steel shackle to help resist cutting and leverage attacks, while a durable vinyl‑coated protective sleeve prevents scratches to your bike’s frame and preserves its finish.
- DOUBLE-DEADBOLT DESIGN: Locks the shackle on both sides of the crossbar for enhanced resistance against twisting and pulling. Certified by Sold Secure Gold, it also includes a high‑security disc‑style cylinder to resist picking and drilling
- VERSATILE SECURITY WITH 4‑FT CABLE: Includes a 4‑ft (120 cm) double‑loop security cable ideal for securing your front wheel, helmet, or accessories. Together with the U‑lock, it is perfect for securing bicycles and e‑bikes at work, school, or around town
- COMPACT, COMMUTER-FRIENDLY SIZE: This U-lock features interior locking dimensions of 3.25” x 7” (8.3cm x 17.8cm) and a total lock weight of 3.55 lbs (1.61 kg), providing a tight fit around bike racks to deter leverage attacks. Weather-treated components help protect against rust and outdoor exposure for reliable everyday use
- EASY MOUNTING BRACKET INCLUDED: Comes with a secure FlexFrame‑U bracket that attaches directly to your bike frame for hassle‑free transport—allowing you to carry the lock easily with no backpack or lock bag required
The Kryptonite Evolution Mini-7 hits most of the marks above: a 13mm hardened shackle, a compact opening, a front-wheel cable and more than 14,000 ratings averaging 4.5 stars. For a full list of options, see our guide to the best bike locks.
FAQ
Is a more expensive bike lock always better?
Not always, but price generally tracks steel quality and thickness. Check the lock type, thickness and an independent rating rather than price alone.
Is Kryptonite a good bike lock brand?
Kryptonite is one of the best-known bike lock brands and its U-locks are widely rated. Its heaviest New York series is aimed at high-theft cities.
What is the best lock for a cheap bike?
A basic U-lock with a cable is usually enough for an inexpensive bike in a low-risk area.
