How to Choose a Bike Lock for City Parking: U-Lock, Folding or Chain

Start with where you park and for how long

How much lock you need depends mostly on two things: where the bike is left and how long it stays there. Kryptonite's lock selection page lays this out as a grid. Its 1–3 ratings cover a brief stop in a rural area. Its 4–6 ratings cover a brief stop in a city, 7–8 cover a full day in a city, and 9–10 cover overnight in a major city. The logic applies whatever brand you buy. A short stop where you can watch the bike needs light security. All-day or overnight street parking in a city is where spending more is worth it.

BikeRadar's lab-tested guide, updated in May 2026, states plainly that "no bike lock is unbreakable." What a lock really buys you is time and noise. If beating it takes several minutes and a power tool, most thieves will move on to an easier bike.

U-lock, folding or chain: what each type does well

BikeRadar tested 12 locks at Abus' test lab in Germany, and the results show the trade-offs between the three main types.

For a bike left outside all workday in a city, these results favour a U-lock as the main lock. A folding lock or chain then works as a second lock or for quick errands.

• U-lock (D-lock): strong for its weight and fairly easy to carry. BikeRadar notes the rigid shape can be awkward, so you may need a cable or a second lock to cover the whole bike. In its angle-grinder test, the Litelok X1 (1.75kg) took about 4 minutes 38 seconds per side, and both sides have to be cut.

• Folding lock: the easiest to carry, but the bars on the tested models were only 5–5.5mm thick. The Abus Bordo Granit is rated Sold Secure Gold, yet a grinder cut it in under 15 seconds. BikeRadar suggests cheaper folding locks for short stops rather than all-day security.

• Chain: useful for awkward anchor points and long stays outdoors, but BikeRadar calls chains fairly heavy. The Squire Chainlok weighs 2.256kg and carries Sold Secure Diamond (pedal cycle). A grinder got through it in 15 seconds. BikeRadar adds that a smaller internal link diameter leaves less room for a lever.

What security ratings actually mean

Sold Secure is a UK test house with a lab in Rugby. It grades bike locks Bronze, Silver, Gold or Diamond. According to BikeRadar's explainer, Bronze locks are usually cables or folding locks that deter opportunists and suit brief stops where you can watch the bike. Silver balances cost and security. Gold resists a wide range of attacks for around five minutes and suits longer stays in public places. Diamond is the top tier, meant to resist prolonged attacks. Testing is voluntary and a lock that fails gets no rating, so a lock without a rating may just never have been submitted.

Sold Secure rates pedal cycles and powered cycles (e-bikes and motorcycles) separately, and the powered criteria are stricter. One lock can be Diamond for pedal cycles but only Gold for powered cycles. TheBestBikeLock.com says Pedal Cycle Diamond and Powered Cycle Gold use the same test criteria, and that Powered Cycle Diamond is reserved for locks with high angle-grinder resistance. Cycling UK's Cycle magazine goes further and says even Diamond has no anti-angle-grinder specification. Sources disagree on how much grinder testing sits behind the pedal ratings, so read Pedal Cycle Diamond alone as no proof of grinder resistance. If grinders worry you, look for Powered Cycle Diamond or independent grinder results.

The Dutch ART foundation uses one to five stars. The foundation says ART 1 and 2 locks must survive several lock-picking attempts with simple tools for a couple of minutes. ART 3 and 4 locks face specialised tools, often with brute force as well, and ART 5 locks are attacked for longer with heavier tools. ART says Dutch bicycle insurance policies require at least two stars, and it recommends ART 3 for bikes at high risk of theft.

Brands also publish their own scales. Kryptonite uses 1 to 10, and Abus gives its locks level numbers, for example 15 on the Bordo Granit in BikeRadar's listing. Kryptonite describes its scale as its own system for ranking its own products. So a Kryptonite 8 tells you nothing when set against another brand's number.

What to pay for and what to skip

Worth paying for:

Usually worth skipping:

• Pay for grinder-resistant material if you park all day or overnight in a city, or ride an e-bike. In Cycling UK's five-minute grinder test, the Kryptonite New York Lock Diamond Standard was only about 10% through one side after 300 seconds and three discs. The OnGuard Rocksolid 8950 was cut through one side in 66 seconds.

• Pay for a design that has to be cut on both sides. Cycling UK notes that the Litelok and OnGuard locks it tested need both sides cut, which roughly doubles the attack time.

• Pay for the right size. Check the shackle dimensions against your frame tubes and local stands. In Cycling UK's test they ranged from 176×82mm (OnGuard) to 223×105mm (Abus).

• Pay for corrosion resistance if you ride in rain or near the sea. In BikeRadar's corrosion test, the Litelok X3 stopped working after 120 hours and the Squire Chainlok and Stronghold D16 Max after 144 hours. BikeRadar recommends a light lube or water repellent from time to time.

• Skip relying on the cable that comes with a U-lock. BikeRadar says the rating covers the D-lock, not the cable, which can usually be cut easily.

• Skip Bronze-rated locks for city parking. They are built to deter opportunists, not to last through an all-day stay.

• Skip a lock heavier than you will actually carry. The Squire Stronghold D16 Max weighs 2.79kg, and a lock left at home protects nothing.

Common mistakes when locking up in a city

• Locking to a short post or sign that a thief can lift the bike over. BikeRadar advises a fixed anchor such as a proper bike stand.

• Leaving the lock loose or resting on the ground. BikeRadar recommends keeping it off the ground and tight to the bike to limit leverage.

• Locking only a wheel. Pass the lock through the frame and the front wheel.

• Using a single lock. BikeRadar suggests two locks of different types and brands, so one set of tools or skills can't beat both.

• Picking a quiet spot. BikeRadar recommends busy locations.

• Assuming your insurer will accept any lock. Check your policy for the rating it requires. Cycling UK notes that the Kryptonite New York Lock Diamond Standard comes with anti-theft insurance (£3,000 in the UK).

Price tiers

Prices below come from BikeRadar's May 2026 update and Cycling UK's December 2025/January 2026 group test. Retail prices change, so treat them as approximate.

• Around £55–£90 ($80–$100): Abus Ultimate 420 (Gold, 1.102kg, around £55/$79.99), Hiplok DXF (Gold, 1.102kg, around £84.99/$99.99) and Squire Chainlok (Pedal Cycle Diamond chain, around £89.99/$97.99). These are tough against hand tools, but in BikeRadar's grinder test they lasted roughly 15 to 45 seconds.

• Around £120–£200: Litelok X1 (Diamond for pedal and powered cycles, ART 4, around £149.99), Abus Bordo Granit folding lock (Gold, around £135/$199.99), Squire Stronghold FL/850 folding lock (Gold, around £154.99) and OnGuard Rocksolid 8950 (Diamond, around £199.99). At 1,428g, the OnGuard was the lightest lock in Cycling UK's test.

• Around £250–£290 ($300 and up): Hiplok D1000 and Litelok X3 (around £249.99/$299.99 each), Abus Granit Superxtreme 2500 (around £270/$299.99) and Kryptonite New York Lock Diamond Standard (around £269.99). They weigh about 1.9–2.4kg, and they lasted longest against grinders in both labs' tests.

Sources

• Best bike locks in 2026: strong, safe bike locks tested in lab conditions (BikeRadar)
• Sold Secure bike lock ratings explained | Diamond, Gold, Silver and Bronze rated locks compared (BikeRadar)
• Group test: Grinder-resistant locks (Cycling UK, Cycle magazine)
• You can recognise a safe, high-quality lock by its ART seal of approval (Stichting ART)
• Sold Secure Diamond bike locks: the list (TheBestBikeLock.com)
• How to choose a lock: 1-10 rating system (Kryptonite)