The watch spring bar, also called a pump bar, is the small component that holds the strap to the case. Choosing the right one is the key to keeping your watch safely on your wrist.

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Measuring the spring bar you need

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Two dimensions to know:

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  • Lug-to-lug width: the distance between the two lugs of the case (10 to 28 mm).
  • Body diameter: 1.3 to 2.0 mm on most watches.
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The types of spring bars

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Standard double-shoulder spring bar

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The benchmark: our stainless-steel double-shoulder spring bar fits 80 % of watches.

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Quick-release spring bar

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Fitted with a side lever, it lets you swap straps without any tool: see the quick-release lever spring bar.

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Rolex-specific spring bar

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Some Rolex models have drilled lugs: use the Rolex-compatible spring bar in the exact length.

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Materials and strength

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MaterialStrengthUse
316L stainless steelHighStandard, diving
Plain steelMediumDress watches
TitaniumHigh, lightweightSport watches
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Fitting

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  1. Compress the spring bar with a positioning awl.
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  3. Insert one end into the lug.
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  5. Compress the other end and guide it into place.
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  7. Check that the spring bar is fully seated on both sides.
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1.8 mm is the most common spring-bar diameter in consumer watchmaking.
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« An undersized spring bar means a strap that falls off at the worst possible moment. »
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FAQ

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How do I find the lug width of my watch?

Use a caliper to measure between the two lugs, or check the model's technical sheet.

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Can a spring bar wear out?

Yes, the inner spring tires over time; replace it every 3 to 5 years with daily wear.

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Steel or titanium spring bar?

316L steel for 95 % of cases; titanium for very lightweight sport watches.

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Are there waterproof spring bars?

The spring bar itself is not waterproof: water resistance comes from the case-back and crown gaskets.

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Written by the Pompe-de-Montre team · Updated 23 May 2026