Shackle size and how to judge bike lock security

Locking area and shackle thickness are different things

People say "shackle size" for two different figures. The locking area is the space inside the shackle, given in mm as width × length. It decides whether the lock fits round your stand and frame.

Shackle thickness is the diameter of the steel itself. A thicker shackle is harder to cut, but it also adds weight.

When should you choose a larger shackle bike lock?

When the lock you'd like to carry won't close round the things you lock to. We'd measure the stand plus the frame tube first. If a compact lock like the Evolution Mini-7 (83 × 178 mm) or the Hiplok D1000 (92 × 155 mm) won't fit, look at a longer shackle.

The OnGuard Pitbull LS 8002 has a 115 × 292 mm locking area and weighs 1.75kg. The ABUS Granit XPlus 540 is 108 × 300 mm at 1.8kg. The Hiplok DX1000 is 112 × 205 mm with a 32 mm shackle, and it weighs 2.75kg.

Here's the catch: a bigger loop leaves more room around the bike once it's locked, and it's more to carry. If a compact lock already closes, it's usually the one you'll keep taking. D1000 vs DX1000 goes through that choice for one pair.

Does a thicker shackle mean a higher grade?

Not on its own. The ABUS Granit XPlus 540 has a 13 mm shackle and is Sold Secure Diamond for ordinary bikes. The Evolution Mini-7 also has a 13 mm shackle and is Gold. The grade depends on how the whole lock performs in Sold Secure's attack testing, including the steel and the locking mechanism.

Thickness does follow the grinder-rated locks, though. The D1000 and DX1000 (both 32 mm, per Hiplok) are Sold Secure Diamond for ordinary bikes and for e-bikes, and both are sold as anti-angle-grinder.

Can customer reviews tell you how secure a bike lock is?

Not really. Owner reviews are useful for fit, keys, the mount and whether the lock rattles. Very few owners have tried to cut their own lock, so star ratings don't tell you much about attack resistance.

For security, we'd go by the Sold Secure grade, which you can check on Sold Secure's approved product search. If your insurer names a grade, that's the one to match. Best bike lock for insurance covers the policy side.

What is the best rated bike lock?

If you mean the Sold Secure rating, Diamond is the top pedal-cycle grade. Several locks reviewed here have it, and they suit different stands and carrying habits. The best of shortlist puts them side by side, and the table below compares the D-locks by size.