As an Amazon Associate, we earn from qualifying purchases. This post contains affiliate links – if you buy through them, we may earn a commission at no extra cost to you.
Finding the best bike lock for Brompton owners is about balancing portability with security. Because these bikes fold into compact shapes, you need a lock that fits your specific frame without adding unnecessary weight. The right choice depends on your daily route, where you park, and how much you value ease of transport. We compare locks that prioritize frame-mounting capabilities, with the Kryptonite locking security standards serving as a guide for your choice. Most riders choose between the convenience of the Kryptolok 685 Folding Lock or the high-security build of the FoldyLock Forever.
1. Kryptolok 685 Folding Lock
Best for: A commuter who needs a lightweight, easy-to-carry folding lock.
This lock uses 5mm hardened steel bars to resist cutting. Its 85cm length gives you enough reach to secure your frame to most bike racks. The rubber coating helps prevent scratching and wear and tear on your bike.
It weighs just 2.35 lbs and includes a bracket for your frame. This makes it a great choice for riders who want to keep their hands free. It isn’t designed for long-term parking in high-theft areas.
Good if:
- You want a balance of weight and security.
- You need a compact design for your frame.
- You prefer a simple, reliable key system.
Skip it if:
- You park in areas with a very high risk of theft.
- You require a longer reach than 85cm.
2. FoldyLock Forever Folding Lock
Best for: Someone who wants the highest level of security in a folding design.
This lock features 0.25-inch hardened steel plates and is rated Sold Secure Gold. It’s built to stop bolt cutters and saws, making it a heavy-duty option for urban environments. The lock opens to a 90cm circumference, giving you more flexibility when locking up.
It includes a frame mount designed to prevent rattling, which keeps your ride quiet. Because of its heavy-duty build, it’s sturdier than basic folding locks. It may feel bulkier than other options for riders who prioritize minimal weight.
Good if:
- You need Sold Secure Gold-rated protection.
- You park your bike outside for longer periods.
- You want a rattle-free mount on your frame.
Skip it if:
- You want the lightest lock possible.
- You prefer a simple, compact design over heavy-duty weight.
3. Evolution Mini-7 Bike U-Lock
Best for: A commuter who wants a compact, high-strength U-lock.
This U-lock features a 13mm hardened steel shackle and a double-deadbolt design. It’s Sold Secure Gold certified, meaning it resists leverage and twisting attacks well. It also includes a 4-ft cable for securing your front wheel or accessories.
The 3.25” x 7” interior space is tight, which helps prevent thieves from using leverage tools. It comes with a FlexFrame-U bracket for easy transport. This lock isn’t for those who find U-locks difficult to maneuver around larger poles.
Good if:
- You want a high-security rating for city use.
- You appreciate having a cable for extra parts.
- You prefer the strength of a solid U-lock.
Skip it if:
- You struggle with the limited locking space of a U-lock.
- You prefer a flexible folding lock.
4. FoldyLock Compact Folding Lock
Best for: The rider who prioritizes a light, easy-to-carry folding lock.
This lock is a winner of the European Design Award and focuses on being lightweight and compact. It opens to a 33.5-inch circumference and uses anti-tamper rivets to stop thieves. It is a weather-proof bicycle protector.
The included bracket holds the lock securely to your bike, ensuring a quiet ride. It’s a Sold Secure Silver-rated tool, offering solid protection for daily errands. It isn’t intended for high-risk, long-duration parking.
Good if:
- You need a reliable, weather-proof design.
- You want a quiet, rattle-free mounting system.
Skip it if:
- You need the highest possible security rating.
- You require extra length for locking to thick poles.
5. Kryptolok 610 S Folding Lock
Best for: Someone who needs a bit more length to reach fixed objects.
This folding lock features 5mm hardened steel links and opens up to 100cm. The added length makes it easier to lock your bike to wider posts or racks. It uses a click-tight bracket that allows for one-handed operation.
At 1.2kg, it remains portable while offering more reach than standard folding locks. It comes with two keys and is eligible for the KeySafe program. It isn’t the best choice if you prefer the absolute smallest lock size.
Good if:
- You often struggle to reach racks with shorter locks.
- You want a simple, one-handed locking mechanism.
- You need a balance of security and extra length.
Skip it if:
- You want the smallest, most compact lock available.
- You only ever lock to thin, standard bike racks.
6. Keeper 785 Chain Lock
Best for: A rider who prefers the flexibility of a chain lock.
This 7mm manganese steel chain provides strong resistance against cutting. It includes a nylon sleeve to protect your bike’s finish from scratches. The integrated design eliminates weak points, making it a reliable choice for moderate security needs.
It is 85cm long, giving you plenty of room to maneuver. It weighs 1.59kg, which is heavier than folding options. It isn’t for riders who want a frame-mounted solution, as it lacks a dedicated bracket.
Good if:
- You prefer a chain over a rigid folding lock.
- You want a flexible lock that’s easy to wrap.
- You need moderate security for your daily stops.
Skip it if:
- You require a frame-mount bracket for your lock.
- You want the lightest possible setup for your bike.
7. Parkview Folding Bike Lock
Best for: A rider who needs a basic, portable lock.
This lock uses 3mm hardened steel bars to provide security for short-term stops. It offers 2.9 feet of locking length, which is quite generous for a folding lock. At just 2.15 lbs, it’s very easy to carry in a pocket or on the frame.
It includes a transport bracket for easy attachment to your bike. It’s built for low to medium risk areas, so it isn’t the right choice for overnight street parking. It’s a simple tool for quick trips.
Good if:
- You want a lightweight and portable option.
- You need extra length for locking to various objects.
- You’re looking for an entry-level folding lock.
Skip it if:
- You park in areas with high theft risk.
- You want the highest-rated hardened steel available.
8. Parkview Bike U-Lock
Best for: A rider who wants a simple, effective U-lock at a good value.
This U-lock features a 12mm hardened steel shackle with an anti-rotation design. It resists bolt cutters and twisting well. Like others, it includes a 4-ft cable for extra security on your front wheel.
It’s lightweight at just 2 lbs, making it easy to carry for daily commuting. The dust cover helps protect the keyway from dirt and weather. It isn’t for those who need a heavy-duty, maximum-security lock for high-theft zones.
Good if:
- You want a straightforward, reliable U-lock.
- You need a cable for your wheels or accessories.
- You want a lightweight lock for daily commuting.
Skip it if:
- You need maximum security for high-risk areas.
- You prefer a folding lock over a U-lock shape.
Where These Overlap
Most of these locks are designed to solve the same problem: securing a bike without adding too much weight. The Kryptolok 685 and the FoldyLock Compact are very similar in their folding approach and portability. If you’re choosing between them, look at the included mounting brackets to see which fits your specific bike frame better. The U-locks, like the Evolution Mini-7 and the Parkview U-Lock, offer a different kind of strength. They’re inherently more rigid and often more secure against leverage than folding locks, but they lack the flexibility of a chain or a folding bar.
Still Not Sure?
How often do you park in public?
If you park your bike every day for work or school, you should prioritize the FoldyLock Forever or the Evolution Mini-7. These offer higher security ratings, which provide greater confidence when leaving your bike unattended for several hours in busy urban areas.
What is your biggest frustration with current locks?
If you’re tired of struggling to reach racks, the Kryptolok 610 S is your best bet due to its extra length. If you’re annoyed by rattling or heavy gear, the FoldyLock Compact is designed specifically to solve those common issues with a quiet, secure mounting system.
Which lock type feels most natural to use?
Some riders prefer the ease of a folding lock, while others like the simplicity of a U-lock. If you like to wrap your lock around odd-shaped objects, the Keeper 785 Chain Lock offers the most versatility. If you prefer a quick, rigid click, go with the Kryptolok 685.
The choice between these locks comes down to your local security needs and your preference for weight versus strength. For high-traffic city areas, the FoldyLock Forever offers strong protection, while the Kryptolok 685 remains a top pick for general portability. Check your bike frame for mounting space before you decide on your final purchase.
Frequently Asked Questions
What has to be replaced to keep it working?
These locks don’t have parts that require regular replacement. The most important thing to manage is your keys. If you lose them, the Kryptonite Key Safe program or the manufacturer’s master key system is your primary way to get back into your lock without cutting it off.
Would the more capable lock have suited me better?
It depends on where you park. If you currently use a folding lock for short stops but find yourself parking in riskier areas, you might feel more secure with a Sold Secure Gold-rated U-lock. The more capable lock provides more resistance, but it often adds weight that you must carry every day.
Final Thoughts
Ultimately, the best choice is the one you’ll actually carry every single day. Don’t let the fear of theft keep your bike locked away at home. Pick the model that fits your routine best, head to your local shop, and grab one today so you’re ready for your next ride.