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Discus padlock vs open shackle

Updated: October 2026

You are choosing between a round discus and a padlock with a U-shaped shackle. Discus padlock vs open shackle is one decision. The discus hides the bar so croppers have little to bite, and it often will not pass a chain. The open shackle reaches further and leaves that bar in the open. Measurements are from the listings in the [disc padlock comparison](/hub/door-and-window-security/disc-padlock) on 19 October 2026. How to read a grade sits on the [disc padlock buying guide](/hub/door-and-window-security/disc-padlock/sub/disc-padlock-buying-guide). Peter F. did not cut locks in a lab. A qualifying purchase can earn a commission at no extra cost to you.

You are choosing between a round discus and a padlock with a U-shaped shackle. Discus padlock vs open shackle is one decision. The discus hides the bar so croppers have little to bite, and it often will not pass a chain.

Our top picks

Burg-Wächter Burg-Wächter Circle 21 70 SB

Best overall

Burg-Wächter Burg-Wächter Circle 21 70 SB
9.4/10about £7.45
View offer
ABUS ABUS Diskus 220/70

Rank 2

ABUS ABUS Diskus 220/70
9.2/10about £19.60
View offer
QWORK QWORK disc lock, 1 pack

Best value

QWORK QWORK disc lock, 1 pack
8.8/10about £5.99
View offer
On this page
  1. 1.What each shape leaves for a cropper
  2. 2.What each shape can pass through
  3. 3.Closed shackle on a policy is not a grade
  4. 4.When a discus, when an open shackle

What each shape leaves for a cropper

An open shackle is a loop standing proud of the body. Insight Security says a longer shackle is easier to attack, and a closed or shrouded shackle is what you choose when cropping is the worry. A discus is one kind of closed shackle: Collections Trust describes the bar sitting in the rim. Collections Trust’s rule of thumb is that under 10 mm has little cropping resistance. The ABUS 220/70 states 10 mm. Burg-Wächter states 9 mm and 10 mm. The Yale Y112 states 7 mm. The QWORK one-pack states no diameter. Neither shape stops an angle grinder.

What each shape can pass through

The discus wins on fit only when the metal is already small. The ABUS 220/70 states 17 mm of clear height and 19.5 mm of clear width. A UK review called the Burg-Wächter 70 mm tight on a motorcycle chain. The Yale Y112 passes more, at 24.8 mm by 20 mm, and gives up thickness with a 7 mm shackle. You do not gain an open shackle. Insight Security keeps open shackles for chains and closed shackles for cropping. If the hasp is a short shed staple, the discus fills it. If you are locking a chain because the hasp is missing, buy the open shackle and then fix the hasp. Sheds and gates are on disc padlock for a shed.
Burg-Wächter Burg-Wächter Circle 21 70 SB

Testsieger

Burg-Wächter Burg-Wächter Circle 21 70 SB
9.4/10about £7.45
View offer

Closed shackle on a policy is not a grade

Nothing But Padlocks treats a discus as closed shackle because the bar is enclosed. A discus from this set can satisfy that line. It does not satisfy CEN 3 or Sold Secure unless the mark is printed. None of these twelve listings shows a Sold Secure mark. Master Lock’s 8/10 and ABUS level 7 are maker scales. BS EN 12320 runs from 1 to 6. The Master Locksmiths Association points outbuildings to Grade 3 fittings as guidance, not as a reason to read a round body as Grade 3. If the email names a grade, a lock that prints it beats a discus that does not.

When a discus, when an open shackle

Choose a discus when the staple is short and the rule says closed shackle without a grade. Check the opening: the ABUS states about 17 mm, and the Burg-Wächter Circle 21, the top pick, states both 9 mm and 10 mm. The QWORK one-pack is the best value only if you can return it when the unstated throat does not close. Choose an open shackle when the chain is thicker than that throat. Choose a lock from outside this set when the paper names CEN Grade 3 or Sold Secure. If the metal will not pass, the hidden shackle will not shut.

Common questions

Which is harder to cut, a discus or an open shackle?
A discus leaves less bar for croppers, which is why closed and shrouded shackles are recommended when cropping is the threat. A short, thick open shackle narrows that gap. A long, thin open shackle widens it. An angle grinder cuts both, so the shape is not a promise against power tools. There is no cutter-time test behind this page.
Which is easier to fit?
The open shackle is easier when the staple is tall, odd, or already wrapped in chain. The discus is easier when the hasp was made for a short loop and you want the bar filled rather than bridged. If the discus will not close, change the lock or the hasp. Do not file the shackle to win the argument.
Can I lock a chain with a disc padlock?
Sometimes a thin single link will pass. A motorcycle chain was already tight on the Burg-Wächter 70 mm in the UK review, and the ABUS 220/70 only offers about 17 mm of clear height. For a real gate chain, use an open shackle long enough for the links and no longer.
Is a discus a closed shackle for insurance?
Retailers that explain UK insurance wording, including Nothing But Padlocks, treat a discus as closed shackle. Your own policy can still ask for a named grade or Sold Secure. The shape meets the first phrase. It does not print the second.
What is a long shackle for?
It reaches a staple set further back, or it passes a chain the discus throat refuses. The extra length is easier to crop, so you only buy as much length as that metal needs. It is the wrong fix for a short shed hasp that a discus would fill.
Does a thicker shackle matter if it is hidden?
Yes. Hiding a 7 mm bar, as on the Yale Y112, still leaves you under the 10 mm rule of thumb that Collections Trust uses. Hiding a stated 10 mm bar, as on the ABUS 220/70, is the stronger discus in this set. Hidden and thick is the point. Hidden and thin is only half of it.
Which should I buy for a hasp, and which for a chain?
A short hasp gets the discus, after you measure the staple against the clearance on the listing. A chain gets an open shackle. If the hasp is short and the policy also names a grade, leave both everyday shapes and buy the lock that prints the grade.

Related pages

Best disc padlock

How to fit a disc padlock

Disc padlock

Disc padlock buying guide: measure the staple first

Disc padlock for a shed, a gate or a storage latch

Sources

BSI, Sold Secure, the Master Locksmiths Association, ProtectUK, Collections Trust, and the amazon.co.uk listings for these twelve ASINs. Prices stored 19 October 2026.

  1. BSI BS EN 12320:2021 padlocks and padlock fittings (retrieved 19 October 2026)
  2. Sold Secure Approved Product Catalogue 2025 (retrieved 19 October 2026)
  3. Master Locksmiths Association minimum security, January 2025 (retrieved 19 October 2026)
  4. ProtectUK: shed and garage door hasps (retrieved 19 October 2026)
  5. Collections Trust, security padlocks, 2024 (retrieved 19 October 2026)
  6. Nothing But Padlocks: which padlock insurance may require (retrieved 19 October 2026)
  7. Insight Security: padlock shackles (retrieved 19 October 2026)
  8. amazon.co.uk listings for these twelve ASINs (retrieved 19 October 2026)