What size chain fits an Oxford Monster Disc lock

Updated on Mar 15, 2026

The Oxford Monster disc lock measures 70mm wide by 135mm high and it has an 11mm shackle.

The gap in the lock is 18mm at its narrowest point. The Monster Disk Lock is also used to secure chains. While its narrowest point is 18mm, it has a wider area at the top of the lock, below the shackle. This means that, if you loop one end of your chain through the other, you can secure it with just a single chain link. Using this method, you can secure chains up to 19mm thick, like our Protector 19mm.

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Thanks for some great products. Your kit protected my bikes perfectly during a burglary a few years ago and it’s still going (extremely) strong.

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I bought from you once and only needed to buy once in 2016, but suffice to say that the 19mm bespoke length chain, and ground anchor installed according to Pragmasis instructions are still going strong, keeping my bike safe just off the street in Brixton, London.

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