Bike chain locks with built-in lock or padlock

Chain with built-in lock, chain and padlock, or lasso?

Three designs share this page. A chain with a built-in lock closes onto a lock body that is part of the product: on Kryptonite's Evolution, the last link is fixed to the hardened bolt to eliminate the weak point at the join. A chain sold on its own is closed with a padlock or a D-lock chosen separately: this is the approach of Auvray's Xtrem chains, offered alone or combined with a D-lock that acts as the padlock. Finally, a lasso chain ends in a ring through which you feed it back to tighten it round a fixed point before locking the other end.

A fourth use is complementary: plug-in chains plug into the lock of a frame lock and attach the bike to a fixed point with a single key.

Link thickness and shape

The thickness of the link gives an idea of the resistance to cutting. On this page, it ranges from 6 mm, for back-up chains such as the Abus IvyTex, to 9 and 10 mm for town use, such as the Abus Steel-O-Chain 9809 or the Kryptonite Evolution, up to 13.5 mm for the Auvray Xtrem. Shape counts too: square or hexagonal links give the jaws of bolt cutters less grip than round links. The treatment of the steel, through-hardened or case-hardened, hardens the link against a saw.

Manufacturers' scales place the models: the Abus Ivy 9210, with 10 mm square links, reaches level 13 out of 15, and the Steel-O-Chain 9809 level 12. To compare two brands, choose independent ratings: in the UK and Ireland, Sold Secure grades bike locks Bronze, Silver, Gold or Diamond, from the lowest resistance to the highest.

What length of bike chain lock do you need, and what weight?

Choose the length according to what you are locking. From 60 to 90 cm, the chain links the frame to a bike stand or a thin post; from 100 to 110 cm, it also goes through a wheel; at 140 and 170 cm, as from Auvray, Abus or Trelock, it goes round a cargo bike, a tree trunk or several bikes. The weight climbs quickly: a 110 cm Seatylock Viking with 7 mm links weighs 1.6 kg, while a 170 cm Abus Ivy with 10 mm links reaches 4.4 kg. The heaviest are carried over the shoulder or in a pannier, or stay put, at home or at work, on a fixed anchor point.

For which bikes and which parking spots?

A chain is the solution for bikes with unusual shapes, cargo bikes, longtails and tricycles, and for places where bike stands are lacking. It often goes with a D-lock or a frame lock to form a double protection of different designs, recommended for an e-bike parked for a long time. At home, combined with an anchor fixed to the floor or the wall, it protects a bike stored in a garage or a shared bike store.

Bike chain lock or D-lock: the other bike locks

For compact protection, see D-locks or folding locks. Plug-in chains combine with frame locks, and anchors and padlocks can be found in other bike locks. All the families are gathered in the bike locks category.

Which bike chain lock brands?

Auvray, a French specialist in two-wheeler locks, has had its Xtrem range certified by the Dutch ART label; its 13.5 mm Xtrem chains are sold alone in 140 or 170 cm, as a lasso or with a D-lock acting as the padlock.

Kryptonite forges the 10 mm hexagonal links of its Evolution chain from manganese steel; the New York series sits at the top of its range, and a 9 mm plug-in chain connects to its frame locks.

Seatylock offers the Viking chain in two levels, Silver and Gold, and in lengths of 90, 110 and 140 cm; the Viking 110 combines 7 mm links with a silicone sleeve.

Abus wraps its chains in a textile sleeve that spares your paintwork and does not absorb water, from the Ivy 9210 with 10 mm square links to the Steel-O-Chain 9809, whose XPlus cylinder is designed to resist picking.

Axa, a Dutch brand, offers the Absolute chain and ULC plug-in chains that lock into its frame locks.

Onguard gives the dimensions in the name of its chains: the Mastiff measures 110 cm with 10 mm links.

Bike chain locks on sale

Chains from replaced series join equipment clearance, and the latest products new arrivals. Black Friday is a chance to add a chain to your D-lock before the long winter nights.

Frequently asked questions

Is a 6 mm chain enough?

As a back-up, for the front wheel or a brief stop within sight, yes. For long stays parked in town, aim for links of at least 9 to 10 mm in hardened steel, combined with a lock of the same level, or add a second lock.

Can you plug a chain into a frame lock?

Yes, provided you choose a compatible plug-in chain: the 9 mm Kryptonite chain fits Kryptonite and Axa frame locks, the ULC fits Axa locks, and Trelock sells its RS 430 frame lock with the ZR 355 chain. The bike is then locked to the fixed point with the key of the frame lock.

Combination or key chain lock?

A combination saves you carrying a key and is easy to share, which suits back-up chains such as the Kryptonite Keeper combination model. High-security chains remain mostly key-operated, with disc cylinders that are more resistant to picking.

How do you lock a cargo bike with a chain?

Pass the chain through the frame itself, not through the box or a removable accessory, then round a solid fixed point. Keep the chain taut and off the ground so that it cannot be rested against the kerb, and if possible add a frame lock on the rear wheel.

What do through-hardened and case-hardened steel mean?

Through-hardening hardens the steel all the way through. Case hardening first enriches the surface with carbon before hardening: it gives a very hard skin, which wears down a saw blade, over a tougher core that does not break under impact.