Frame locks (ring locks) and how they pair with other locks

A ring lock is the little horseshoe bolted next to the rear tire. You close it in a second. Handy? Yes. But it's easy to mistake it for a full lock, and it isn't one.

What it does

A ring lock is fixed to the frame, next to the rear tire. When you close it, a steel bolt slides through the spokes so the wheel can't turn. Wikipedia calls it a low security mechanism¹.

That stops anyone riding off. It also forces a thief to carry the bicycle¹. For a quick stop, that's a useful speed bump.

Other names for it are wheel lock, frame lock and O-lock. They all mean the same kind of lock. On the shop floor you'll hear all four.

Chicago's advice applies here too: always lock your bike, even if you're leaving it for only a moment².

What it doesn't do

A ring lock prevents riding the bicycle but does not, by itself, secure the bicycle to a stationary object¹. So the whole bike, wheel and all, can still be picked up and taken.

Think of it as a brake on the wheel. Not an anchor.

Pairing it with other locks

There are two usual ways to finish the job.

• A plug-in chain or cable. Many models have an optional cable or chain that plugs into the body of the lock¹. One maker says its plug-in option allows the bicycle to be secured to a fixed object with locking of the ring lock and plug-in in only one action³. That's one maker's description of one product, so check what your own lock supports.
• A separate U-lock. Used in addition to a U-lock, a ring lock can be a convenient second lock¹.

In both cases the second lock does the anchoring. Chicago's city page makes a related point about the other wheel. It suggests a cable or a second U-lock².

A note about the front wheel

The ring lock covers the rear wheel only. If your front wheel comes off easily, it still needs its own protection. Wikipedia says the ring lock secures the rear wheel, so locking the frame covers both frame and rear wheel¹. The front wheel is a separate job.

At the counter

Is there a built-in ring lock on the e-bike you're eyeing? Ask what plug-in options exist. Check whether the maker's manual covers them. Then plan on carrying a second lock.

Anchors are covered on the frame, wheels and anchors page, and the other lock shapes are on the types page. Ring locks differ between makers, so follow your own lock's manual for fitting and use.