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Cylinder Measuring Guide

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We strongly suggest that you read our measuring method below to avoid ordering the incorrect size  lock cylinders. We can guarantee that by employing our method, you will not get it wrong!

IT IS ESSENTIAL that the old cylinder is removed from the door for measuring, as accurate measurement is very difficult to achieve whilst the cylinder is installed.

Removing the old cylinder from the door will also confirm your ability to carry out the work, before purchasing a new lock.

Ideally your new  cylinder should sit as flush as possible BUT NOT INSIDE THE FACE OF THE HANDLES. Please note it is unlikely that a perfectly flush fit is achievable! .
 With 3 star anti-snap locks your security is not affected if your cylinder protrudes but it will appear more aesthetically pleasing if less than 5mm.
Check Out the video below to help you remove and replace your lock;


Measure from the centre of the fixing bolt hole to the marks/ends of each side of your cylinder NEVER MEASURE TO THE BLACK CAM . Lock cylinders are available in 5mm increments per side . Measured correctly, adding the internal and external sizes together should result in the total overall length of your cylinder e.g 35 internal + 45 external = 80mm overall.
Thumbturn Cylinders - Do not add the thumbturn onto the internal dimension.  
Download ABS Measuring & Fitting Guide HERE

Always use a ruler - tape measures are not accurate
Always quote the internal size first , followed by the external size.
Please do not assume that all your locks are the same size - This is seldom the case!