Before you choose a digital cylinder, there's a crucial question to answer: What length does your new cylinder need to be to fit perfectly in your door? With a few simple steps, you can find this out in under two minutes. In this guide, we'll show you step-by-step how to correctly measure the cylinder length so that your new ELCON digital cylinder fits right away.
Why the right cylinder length is so important
A digital cylinder must precisely match the thickness of your door. If it's too short, it won't close properly or may not even be installable. If it's too long, it will protrude unsightly from the door and can become a security vulnerability. A cylinder is only break-in proof if it closes cleanly both inside and out.
The good news: measuring the correct length is easy. You only need a folding rule or a tape measure and about two minutes of your time.
What you need to know: Cylinder length consists of two values
A profile cylinder is always specified with two measurements, for example, 30/35 mm. These values stand for:
- Internal dimension: The part of the cylinder that faces the inside of your apartment or house
- External dimension: The part that faces outwards, i.e., towards the entrance side
Both values are measured from the center of the mortise screw, which is the screw that secures the cylinder in the lock. This screw is usually visible on the side of the door when it is open.
Step-by-step: How to measure the cylinder length
Step 1: Open the door and find the mortise screw
Open your door and look at the narrow side (where the door closes). You will see a narrow metal strip there, which is the mortise. In the middle of this mortise, there is a screw that secures the locking cylinder. This is the mortise screw and also your measurement reference point.
Step 2: Measure the internal dimension
Measure from the center of the mortise screw to the outermost point of the cylinder on the inside of your door (i.e., where you are when the apartment door is closed).
Note down the value in millimeters.
Step 3: Measure the external dimension
Now you measure the counterpart: from the center of the mortise screw to the outermost point of the cylinder on the outside of your door.
Note down this value in millimeters as well.
Step 4: Combine the values
Write down the two values in the format Inside/Outside, for example, 30/35 mm. You will need this information when ordering your new digital cylinder.
Tips for an accurate result
- Always measure from the mortise screw. Not from the door leaf, not from the fitting. The mortise screw is the only reliable reference point.
- Round to 5 mm. Profile cylinders are manufactured in 5 mm increments (e.g., 30, 35, 40, 45 mm). If your measurement is between two values, choose the next largest.
- Two different values are normal. Internal and external dimensions are rarely the same. For most doors, the outside is a few millimeters longer because a fitting or protective fitting is additionally mounted there.
- If in doubt, measure again. A cylinder that is 5 mm too short cannot be installed, and one that is too long protrudes and can be a security risk.
Which ELCON digital cylinders fit your door?
Once you know the measurements, you'll find the right digital cylinder in the ELCON range:
- ELCON EL2: Our compact digital cylinder for private households and small commercial properties. Bluetooth, app control, and optional remote function via the ELCON Bridge.
- ELCON EL20: The advanced version with additional functions for more demanding applications.
Both models are available in various length combinations. An overview can be found on the category page for smart digital cylinders.
Even simpler: the ELCON compatibility check
Don't want to measure yourself or are unsure about your values? Then use the ELCON compatibility check. In a few steps, you answer a few questions about your door, and the tool recommends the right model with the correct length. This way, you can be sure that your new digital cylinder will fit right away.
Conclusion
Finding the correct cylinder length is not rocket science. With a folding rule, the mortise screw as a reference point, and two clean measurements, you'll have all the data you need in under two minutes. If you're still unsure, the configurator will help you with the final check.
So nothing stands in the way of your switch to smart access.
Discover digital cylinders now or go directly to the compatibility check.
