How to Get the Correct Size Spring Bars for Your Watch: A Simple Guide

by Luxury Watch Straps

See our collection of superb spring bars / watch pins here.

Spring bars: the unsung heroes of the watch world. These tiny metal rods are what keep your strap attached to your watch case, yet they rarely get the attention they deserve—until one goes flying across the room, never to be seen again. Whether you're swapping out a strap or replacing a worn-out bar, getting the correct size is absolutely essential. Too long and they won’t fit; too short and your watch could end up on the floor (or worse, down a drain).

Here’s a simple, no-fuss guide to help you get the right size spring bars for your watch.

1. Understand What a Spring Bar Is

A spring bar is a small, spring-loaded metal rod with flanges at both ends. It fits inside the lugs of your watch and passes through the holes at the end of the strap. When you compress the bar, the ends retract, allowing you to slot it in or out of the lug holes.

They may be small, but they’re mighty—and choosing the right size is key to keeping your watch secure and comfortable.

2. Measure the Lug Width

The most important measurement you need is the lug width—the distance between the two “arms” (or lugs) of your watch case. This is where the strap fits in, and it’s also where your spring bar sits.

Here’s how to measure it:

  • Use a digital caliper (or a good old-fashioned ruler, if necessary).

  • Measure in millimetres from the inside edge of one lug to the inside edge of the other.

Common lug widths include 18mm, 20mm, 22mm and 24mm, but they can vary—especially with vintage or fashion watches.

3. Match the Spring Bar Length

Once you know your lug width, get spring bars that match exactly. For example, a 20mm lug width needs 20mm spring bars. Don’t guess or assume—1mm too short, and the bar won’t stay in place; 1mm too long, and it won’t compress properly.

Some sellers label bars by their fitted length (the compressed size when installed), while others may include the shoulder size (total end-to-end). Always check the specification or ask the supplier if unsure.

4. Choose the Right Type

Spring bars come in various styles, including:

  • Standard: Great for most leather or NATO straps.

  • Fat bars: Thicker and stronger—ideal for dive watches.

  • Quick-release: Have tiny levers for tool-free strap changes.

  • Double-flange: Easier to remove using a spring bar tool.

Make sure the bar diameter matches your watch lug holes. Most use 1.5mm or 1.8mm thickness, but dive watches might need 2.0mm or more.

5. Buy a Few Spares (Trust Us)

Spring bars have a way of vanishing into thin air the moment you drop them. Always have a few extras in the correct size—your future self will thank you.

Final Tip

Don’t force it. If a bar doesn’t slide in smoothly, stop and re-check your measurements. A poorly fitting spring bar could damage your watch—or worse, lead to a costly drop.

With the right size and a steady hand, you’ll have your strap swapped and your watch back on your wrist in no time.

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