Spring Bar
A spring bar is the small metal pin with an internal spring that holds a strap or bracelet between the watch lugs. Its sprung tips compress and seat into the lug holes, and a simple spring-bar tool lets you press them in to swap a strap at home.
At a glance
- Job
- Holds the strap between the lugs
- Tool needed
- Forked spring-bar tool
- Sizing
- Equal to lug width, in millimeters
The part that joins your watch case to its strap is easy to overlook, yet it is exactly what lets you change a strap yourself. It is a hollow tube with a spring inside and two thin tips that push outward at each end.
How it holds
The tips are pushed out by spring pressure and seat into small holes on the inner face of the lugs. To remove a strap you compress one tip to free it, and the spring releases the other side as you angle the bar out.
- Right size: the bar length must match the lug width exactly, measured in millimeters
- Right tool: a forked spring-bar tool lets you press the tip without scratching the case
- Keep spares: bars are thin and fatigue over time, so a cheap pack is worth having
Changing a strap at home
The same bar holds a leather strap or a steel bracelet in place, so you can change how one watch looks in minutes. For a step-by-step start, see our guide to the best watches for beginners.
Examples
On a watch with 20 mm lugs, moving from a leather strap to a NATO strap takes only a 20 mm spring bar and a forked tool.
Comparison
A standard spring bar and a quick-release bar differ in how easily you swap straps.
| Option A | Option B | Notes |
|---|---|---|
| Standard spring bar | Quick-release spring bar | A standard bar needs a tool; a quick-release bar has a tiny lever you pull with a fingernail, so no tool is required. |
Related terms
Frequently asked questions
Can I change a strap without a spring-bar tool?
With quick-release bars you can, since a small lever you pull by hand frees the strap without a tool. For standard spring bars, a forked tool is the safe way to compress the tip and avoid scratching the case.
What size spring bar do I need?
The bar length should equal your watch's lug width, measured in millimeters, with 18, 20, and 22 mm being the most common. The safest method is to remove the existing bar and measure it, or measure the gap between the lugs.
Do spring bars break?
Yes, spring bars are thin and can fatigue, bend, or snap over time, especially if you change straps often. Keeping a few spares in the correct size and replacing a tired bar promptly stops the watch from falling off your wrist.