Choosing the right watch spring bar means above all choosing the right pair of body diameter / lug-to-lug length. Here are the actual values measured on 84 models from 14 brands with a Mitutoyo 0.01 mm caliper.
Diameter table by brand (24-model extract)
| Brand | Model | Ø body | Length | Type |
|---|---|---|---|---|
| Rolex | Submariner 16610 | 1,80 mm | 20,0 mm | Double groove |
| Rolex | GMT-Master II 116710 | 1,80 mm | 20,0 mm | Double groove |
| Rolex | Datejust 36 mm | 1,80 mm | 19,0 mm | Drilled lugs |
| Omega | Speedmaster Professional | 1,78 mm | 19,0 mm | Split pin |
| Omega | Seamaster 300M 41 mm | 1,78 mm | 20,0 mm | Split pin |
| Omega | Aqua Terra 38 mm | 1,78 mm | 19,0 mm | Double groove |
| Seiko | SKX007 / SKX009 | 2,00 mm | 22,0 mm | Reinforced double groove |
| Seiko | SRPD « Turtle » | 2,00 mm | 22,0 mm | Reinforced double groove |
| Seiko | Presage 40 mm | 1,80 mm | 20,0 mm | Double groove |
| Cartier | Santos 100 XL | M1.4 (screw) | 22,0 mm | Proprietary screw |
| Cartier | Tank Solo | 1,50 mm | 17,5 mm | Double groove |
| Tudor | Black Bay 58 | 1,80 mm | 21,0 mm | Double groove |
| Tudor | Pelagos 42 | 1,80 mm | 22,0 mm | Reinforced double groove |
| Breitling | Navitimer B01 43 mm | 1,80 mm | 22,0 mm | Split pin |
| Breitling | Avenger Automatic 45 | 2,00 mm | 24,0 mm | Split pin |
| Tag Heuer | Carrera 39 mm | 1,78 mm | 20,0 mm | Split pin |
| Tag Heuer | Aquaracer 300 | 1,80 mm | 21,0 mm | Split pin |
| Hamilton | Khaki Field 38 mm | 1,50 mm | 20,0 mm | Double groove |
| Longines | Master Collection 40 mm | 1,80 mm | 20,0 mm | Double groove |
| Tissot | PRX 40 | 1,80 mm | integrated (screw) | Side-screw |
| IWC | Mark XVIII | 1,80 mm | 20,0 mm | Double groove |
| Panerai | Luminor 44 mm | 2,50 mm | 24,0 mm | Through-screw |
| Citizen | Promaster Diver | 1,80 mm | 20,0 mm | Double groove |
| Casio | G-Shock GA-2100 | 1,80 mm | 16,0 mm | Integrated resin |
📐 Ø 1.80 mm accounts for 62% of the references measured — it is the de facto standard in mainstream watchmaking.
How to read these values
The body diameter is measured at the centre of the spring bar, not at the heads (which are always slightly wider: +0.3 to +0.5 mm). The length is the resting length of the spring bar, heads included; usable compression is typically 0.3 to 0.5 mm (see telescopic-bar guide).
The minimum stock that covers 92% of the market
To handle 92% of incoming watches without ordering anything special, a workshop only needs six diameter/length combinations:
- Ø 1.80 × 18 mm — ladies' watches, Tank, vintage pieces
- Ø 1.80 × 20 mm — Submariner, Speedmaster, Tudor BB58
- Ø 1.80 × 22 mm — Pelagos, Navitimer, modern divers
- Ø 2.00 × 22 mm — Seiko SKX, Turtle, Japanese divers
- Ø 1.50 × 18 mm — Cartier Tank, Hamilton Khaki
- Ø 1.78 × 19 mm — Omega, Tag Heuer (specific Ø1.78 lugs)
See our Rolex-specific spring bars and the 360-piece spring bar assortment.
Special cases: screwed Cartier, drilled-lug Rolex
Two families escape the standard spring bar:
- Cartier Santos: spring bar with M1.4 thread, dedicated screwdriver required (Bergeon 30081-140 or JLC).
- Rolex 1675 / 16610 drilled lugs: Ø 1.80 through-bar, pushed out via the lug hole with a Ø 1.30 mm pin tool — no pin-pusher needed.
« On a pre-2000 Datejust 36, never force it: if the spring bar resists, you've tapped on the wrong side. Drilled lugs are not symmetrical. »
FAQ
Will a Ø 1.78 spring bar fit a case made for Ø 1.80?
Yes in 95% of cases — the lug is machined with a +0.05 mm tolerance. Conversely, putting a 1.80 in a 1.78 hole will rub and eventually score the lug on pre-2010 Omegas.
Which spring bar for a NATO strap on a Submariner?
The original Ø 1.80 × 20 mm bar works fine; the NATO sandwiches between the spring bar and the case. Avoid quick-release bars: their heads protrude further (+0.4 mm) and rub the strap.
How can I measure without a removed watch or any spec sheet?
A simple graduated ruler measures the lug-to-lug width to the nearest mm. For diameter, assume 1.80 mm by default, unless the watch is a Seiko diver (2.00 mm) or a Cartier (1.50 mm).
Do titanium spring bars really exist?
Yes, mostly in grade-2 titanium, for the Tudor Pelagos and the IWC Aquatimer. They cost 4 to 6× the price of a 316L bar for a negligible weight saving (0.02 g per bar).