Which spring bar does my watch need?
A spring bar has two sizes. Its length is the lug width of the watch: the gap between the two lugs, in whole millimetres. Its diameter is decided by the brand: Rolex, Omega and Tudor take their own spring bars; most other watches take a standard Swiss spring bar of 1.8 mm.
Watch references whose lug width has been measured on this site. For each of them, that number is the length of the spring bar the watch takes.
The length is the lug width of the watch
A spring bar sits inside the gap between the lugs, with its two tips pushed into the holes drilled in the lugs. Its length is therefore the lug width of the watch, in whole millimetres: a 20 mm lug width takes a 20 mm spring bar. One millimetre short and the spring bar can slip out of the lug under load; one millimetre long and it does not go in. Search your reference on this site for the measured lug width, or measure the gap yourself with the measuring guide.
Rolex, Omega and Tudor take their own spring bars
On these brands each model has its own length and diameter, and the wrong spring bar either does not seat in the lug or wears it. For Rolex, Omega and Tudor we stock the spring bar made for the model: by reference, by lug width of the watch, and for drilled lugs where the case has them.
- Spring bars for Rolex watches: modern and vintage cases, Submariner, GMT-Master II, Daytona.
- Spring bars for Omega watches: 20 and 22 mm, 1.8 mm in diameter, and the 18 to 23 mm set.
- Spring bars for Tudor watches: modern cases, to the factory specification.
Most other watches take a standard spring bar
A good Swiss double-flange spring bar, 1.8 mm in diameter, in the length of the lug width of the watch, fits the great majority of watches from 13 to 26 mm. Pick the length from the page of your reference; the diameter follows: 1.8 mm unless the brand says otherwise. The tips of the spring bar matter as much as the body: a tip too thick does not enter the lug hole, a tip too thin moves in it. Spring bars by brand and size.
Watches with drilled lugs
On 174 references in our database the lug holes go through the lug and are visible from the outside. On these watches a spring bar is released by pushing a thin tool into the hole from outside: faster, and with no tool touching the case between the lugs. The page of each watch reference says whether its lugs are drilled.
Spring bars with a quick-release lever
A quick-release spring bar has a small lever on its body, so the watch strap can be changed without any tool. It works only with a watch strap made with the slot for that lever, and its length and diameter follow the same rules as any other spring bar.
The two things not to do
- Do not reuse a bent or worn spring bar. It is the only part holding the watch to the wrist.
- Do not guess the diameter from the lug width. The two numbers are independent: a 20 mm watch can take a 1.5, 1.8 or 2.0 mm spring bar.
With the right spring bar in hand, the guide to changing a watch strap shows the five steps, without marking the case.
Check your own reference
Family averages are the reason people order the wrong size. Your reference has its own measured number, and it is in the database.
Search your referenceOther questions
- Why will no strap fit my watch?5.7% of watches have no lug width at all. Here is what to do instead.2,640
- What length watch strap do I need?Ready-made straps come in one length only. Whether that length reaches you is a different question.75/115 mm
- What size watch band do I need?The watch decides the width, your wrist decides the length. The three ways to find the width, in order, and the mistake to avoid.
- How do I change a watch strap?A spring bar tool and five minutes. The two facts to know first, the five steps, and the pull-test that is the only check you have.